Elasmobranchs

The author commences by stating that the observations recorded in his paper have been made upon the three following genera of Elasmobranchs—ScyIlium, Pristiurus, and Torpedo. The majority of his observations were made upon specimens procured for him through the agency of the Zoological Station at Naples; but he has also been supplied in a most liberal manner with Scyllium embryos by the Directors of the Brighton Aquarium, through the kindness of Mr. Henry Lee. He finds that Torpedo embryos are by far more suitable than any other genera he has employed for the investigation of the development of the nerves.

@article{balfour1876on,
    author = "Balfour, Francis Maitland",
    title = "On the development of the spinal nerves in elasmobranch fishes",
    year = "1876",
    journal = "Proceedings of the Royal Society of London",
    abstract = "The author commences by stating that the observations recorded in his paper have been made upon the three following genera of Elasmobranchs—ScyIlium, Pristiurus, and Torpedo. The majority of his observations were made upon specimens procured for him through the agency of the Zoological Station at Naples; but he has also been supplied in a most liberal manner with Scyllium embryos by the Directors of the Brighton Aquarium, through the kindness of Mr. Henry Lee. He finds that Torpedo embryos are by far more suitable than any other genera he has employed for the investigation of the development of the nerves.",
    url = "https://doi.org/10.1098/rspl.1875.0014",
    doi = "10.1098/rspl.1875.0014",
    number = "164-170",
    openalex = "W3092424191",
    pages = "134-136",
    volume = "24"
}

@misc{balfour1878a,
    author = "Balfour, Francis M.",
    title = "A monograph on the development of elasmobranch fishes / by F. M. Balfour.",
    year = "1878",
    url = "https://doi.org/10.5962/bhl.title.7847",
    doi = "10.5962/bhl.title.7847",
    openalex = "W2503935562"
}

@misc{balfour1878a1,
    author = "Balfour, F. M",
    title = "A Monograph on the Development of Elasmobranch Fishes",
    year = "1878",
    howpublished = "London, Macmillan",
    note = "talkorigins\_source = {true}; raw\_reference = {Balfour, F. M., 1878, A Monograph on the Development of Elasmobranch Fishes: London, Macmillan.}"
}

@article{doi101038018113a0,
    author = "Lankester, E. Ray",
    title = "A Monograph on the Development of Elasmobranch Fishes",
    year = "1878",
    journal = "Nature",
    url = "https://doi.org/10.1038/018113a0",
    doi = "10.1038/018113a0",
    openalex = "W2107131948"
}

@book{doi105962bhltitle7847,
    author = "Balfour, Francis M.",
    title = "A monograph on the development of elasmobranch fishes / by F. M. Balfour.",
    year = "1878",
    url = "https://doi.org/10.5962/bhl.title.7847",
    doi = "10.5962/bhl.title.7847",
    openalex = "W2503935562"
}

@article{lankester1878a,
    author = "LANKESTER, E. RAY",
    title = "A Monograph on the Development of Elasmobranch Fishes",
    year = "1878",
    journal = "Nature",
    url = "https://doi.org/10.1038/018113a0",
    doi = "10.1038/018113a0",
    number = "448",
    openalex = "W2107131948",
    pages = "113-115",
    volume = "18"
}

ABSTRACT The development of the Lamprey has occupied the attention of many embryologists during the last fifty years. Of these we owe the most complete accounts of the changes through which the egg passes to Max Schultze, Owsjannikow, Calberla, Scott, Balfour, and Dohrn. I have recently worked through the development of Petromyzon again, and worked out the origin of several organs which have hitherto been incompletely known. In many of the most important points my researches confirm those of the earlier observers, and to these I have only referred at such length as would make the account intelligible; in others, such as the persistence of the blastopore, the origin of the ventral mesoblast, &c., I differ from previous descriptions; and some points, such as the development of the heart, of the parts of the brain and cranial nerves, are worked out for the first time.

@article{doi101242jcss227107325,
    author = "Shipley, A. E.",
    title = "On Some Points in the Development of Petromyzon fluviatilis.1",
    year = "1887",
    journal = "Journal of Cell Science",
    abstract = "ABSTRACT The development of the Lamprey has occupied the attention of many embryologists during the last fifty years. Of these we owe the most complete accounts of the changes through which the egg passes to Max Schultze, Owsjannikow, Calberla, Scott, Balfour, and Dohrn. I have recently worked through the development of Petromyzon again, and worked out the origin of several organs which have hitherto been incompletely known. In many of the most important points my researches confirm those of the earlier observers, and to these I have only referred at such length as would make the account intelligible; in others, such as the persistence of the blastopore, the origin of the ventral mesoblast, \&c., I differ from previous descriptions; and some points, such as the development of the heart, of the parts of the brain and cranial nerves, are worked out for the first time.",
    url = "https://doi.org/10.1242/jcs.s2-27.107.325",
    doi = "10.1242/jcs.s2-27.107.325",
    openalex = "W2552515367"
}

ABSTRACT It is now more than ten years ago since I first pointed out the inadequacy of the cellular theory of development. That I did so in a very guarded manner need hardly be said; but now, after ten years of mature work, I feel justified in giving a stronger expression to the views which I then formed, and which all my subsequent work has amply confirmed. My words then (in 1883) were as follows:—” In short, if these facts are generally applicable, embryonic development can no longer be looked upon as being essentially the formation by fission of a number of units from a single primitive unit, and the co-ordination and modification of these units into a harmonious whole. But it must rather be regarded as a multiplication of nuclei and a specialisation of tracts and vacuoles in a continuous mass of vacuolated protoplasm.” Again, in 1888, in the preface to my “Monograph on the Development of the Cape Species of Peripatus,” 1 I wrote: “It would appear, indeed, that in Peripatus the cells of the adult, in so far as they are distinct and sharply marked off structures, are not, as appears to be generally the case, present in the earliest embryonic stages, but are gradually evolved as development proceeds. In other words, the cell-theory, if it implies that the adult cells are derived from embryonic cells which have been directly produced by the division of the ovicell, does not apply to the embryos of Peripatus.”

@article{doi101242jcss23714587,
    author = "Sedgwick, Adam C.",
    title = "On the Inadequacy of the Cellular Theory of Development, and on the Early Development of Nerves, particularly of the Third Nerve and of the Sympathetic in Elasmobranchii",
    year = "1894",
    journal = "Journal of Cell Science",
    abstract = "ABSTRACT It is now more than ten years ago since I first pointed out the inadequacy of the cellular theory of development. That I did so in a very guarded manner need hardly be said; but now, after ten years of mature work, I feel justified in giving a stronger expression to the views which I then formed, and which all my subsequent work has amply confirmed. My words then (in 1883) were as follows:—” In short, if these facts are generally applicable, embryonic development can no longer be looked upon as being essentially the formation by fission of a number of units from a single primitive unit, and the co-ordination and modification of these units into a harmonious whole. But it must rather be regarded as a multiplication of nuclei and a specialisation of tracts and vacuoles in a continuous mass of vacuolated protoplasm.” Again, in 1888, in the preface to my “Monograph on the Development of the Cape Species of Peripatus,” 1 I wrote: “It would appear, indeed, that in Peripatus the cells of the adult, in so far as they are distinct and sharply marked off structures, are not, as appears to be generally the case, present in the earliest embryonic stages, but are gradually evolved as development proceeds. In other words, the cell-theory, if it implies that the adult cells are derived from embryonic cells which have been directly produced by the division of the ovicell, does not apply to the embryos of Peripatus.”",
    url = "https://doi.org/10.1242/jcs.s2-37.145.87",
    doi = "10.1242/jcs.s2-37.145.87",
    openalex = "W2601095885"
}

The purpose of the following paper is a description of various typical stages in the development of the back, the limbs, and the body-wall in man.The work is based primarily upon reconstructions, according to the method of Born,' of parts of five human embryos; it has been extended and controlled by a study of the external form and of serial sections of several other human embryos.Dr. Lewis has devoted special study to the formation of the arm, Dr. Bardeen to that of the leg, the bodp-wall and the back.I n the accompanying table a list is given of the embryos utilized.Those marked with an asterisk have been reconstructed.We shall consider the early stages in the development of the limbs, the body-wall and the back, first, from the point of view of the external form and, secondly, from that of internal structural differentiation.

@article{doi101002aja1000010102,
    author = "Bardeen, Charles Russell and Lewis, Warren",
    title = "Development of the limbs, body‐wall and back in man",
    year = "1901",
    journal = "American Journal of Anatomy",
    abstract = "The purpose of the following paper is a description of various typical stages in the development of the back, the limbs, and the body-wall in man.The work is based primarily upon reconstructions, according to the method of Born,' of parts of five human embryos; it has been extended and controlled by a study of the external form and of serial sections of several other human embryos.Dr. Lewis has devoted special study to the formation of the arm, Dr. Bardeen to that of the leg, the bodp-wall and the back.I n the accompanying table a list is given of the embryos utilized.Those marked with an asterisk have been reconstructed.We shall consider the early stages in the development of the limbs, the body-wall and the back, first, from the point of view of the external form and, secondly, from that of internal structural differentiation.",
    url = "https://doi.org/10.1002/aja.1000010102",
    doi = "10.1002/aja.1000010102",
    openalex = "W2050962411"
}

In the following paper some observations are reported concerning the embryonic morphology of the acoustic nerve and the development of the ganglion mass incorporated in its trunk.The differentiation of this latter mass, the ganglion acusticum, and its subdivision into the ganglion vestibulare and the ganglion spirale present several features of interest; and deserving of especial attention is the additional light which the study of this process throws upon the question of nerve supply of the saccule, and the ampulla of the posterior semi-circular canal.It is found, namely, that these two portions of the membranous labyrinth are not supplied by the cochlear nerve, as described in English and German text books, but are supplied by the vestibular nerve, as has been maintained by some of the French writers.This brings all of the ampulls together with the utricle and saccule under control of the same nerve, and leaves the cochlear nerve as a specialized and distinct nerve for itself, supplying only the cochlear duct.This arrangement is one which should be gratifying to the physiologist, for it draws a definite line between that portion of the nerve complex which controls the analysis of sound and that which controls equilibrium.

@article{doi101002aja1000060103,
    author = "Streeter, George L.",
    title = "On the development of the membranous labyrinth and the acoustic and facial nerves in the human embryo",
    year = "1906",
    journal = "American Journal of Anatomy",
    abstract = "In the following paper some observations are reported concerning the embryonic morphology of the acoustic nerve and the development of the ganglion mass incorporated in its trunk.The differentiation of this latter mass, the ganglion acusticum, and its subdivision into the ganglion vestibulare and the ganglion spirale present several features of interest; and deserving of especial attention is the additional light which the study of this process throws upon the question of nerve supply of the saccule, and the ampulla of the posterior semi-circular canal.It is found, namely, that these two portions of the membranous labyrinth are not supplied by the cochlear nerve, as described in English and German text books, but are supplied by the vestibular nerve, as has been maintained by some of the French writers.This brings all of the ampulls together with the utricle and saccule under control of the same nerve, and leaves the cochlear nerve as a specialized and distinct nerve for itself, supplying only the cochlear duct.This arrangement is one which should be gratifying to the physiologist, for it draws a definite line between that portion of the nerve complex which controls the analysis of sound and that which controls equilibrium.",
    url = "https://doi.org/10.1002/aja.1000060103",
    doi = "10.1002/aja.1000060103",
    openalex = "W1909269994",
    references = "doi101002aja1000040106"
}

Including Families and Genera as Far as Known Class LEPTOCARDII (Myelozoa) Order AMPHIOXI (Cirrostomi) The Lancelets (or Leptocardii) are without doubt simplest in organiza tion of all fish-like chordates or vertebrates.

@book{doi105962bhltitle161386,
    author = "Jordan, David Starr",
    title = "A classification of fishes: including families and genera as far as known",
    year = "1923",
    booktitle = "Stanford University Press eBooks",
    abstract = "Including Families and Genera as Far as Known Class LEPTOCARDII (Myelozoa) Order AMPHIOXI (Cirrostomi) The Lancelets (or Leptocardii) are without doubt simplest in organiza tion of all fish-like chordates or vertebrates.",
    url = "https://doi.org/10.5962/bhl.title.161386",
    doi = "10.5962/bhl.title.161386",
    openalex = "W658957599"
}

@article{doi101038124440c0,
    title = "The Elasmobranch Fishes",
    year = "1929",
    journal = "Nature",
    url = "https://doi.org/10.1038/124440c0",
    doi = "10.1038/124440c0",
    openalex = "W1523656269"
}

Abstract This paper, which is based on investigation of Acipenser, Polypterus, Amia and Lepidosteus, is written partly to supplement, partly to amend, some scanty notes which I published on the subject in 1911. Observations on Plagiostomi, Teleostei and Amphibia, which have a bearing on the problems discussed, are incorporated in the paper. The Ocular Muscles. The study of the development of the ocular muscles was begun by Balfour (1878), who stated that it is probable that the walls of the 1st head-cavity of Selachian embryos develop into the external ocular muscles. Marshall (1881) stated that the Recti superior, internus and inferior, and probably the Obliquus inferior, are derived from the walls of the 1st head-cavity. He did not find the origins of the Obliquus superior and Rectus externus, but in regard to the latter said that it is probable that it is developed from the walls of the dorsal ends of the 2nd and 3rd head-cavities.

@article{doi101098rstb19290002,
    author = "Edgeworth, F. H.",
    title = "II. The development of some of the cranial muscles of ganoid fishes",
    year = "1929",
    journal = "Philosophical Transactions of the Royal Society of London Series B Containing Papers of a Biological Character",
    abstract = "Abstract This paper, which is based on investigation of Acipenser, Polypterus, Amia and Lepidosteus, is written partly to supplement, partly to amend, some scanty notes which I published on the subject in 1911. Observations on Plagiostomi, Teleostei and Amphibia, which have a bearing on the problems discussed, are incorporated in the paper. The Ocular Muscles. The study of the development of the ocular muscles was begun by Balfour (1878), who stated that it is probable that the walls of the 1st head-cavity of Selachian embryos develop into the external ocular muscles. Marshall (1881) stated that the Recti superior, internus and inferior, and probably the Obliquus inferior, are derived from the walls of the 1st head-cavity. He did not find the origins of the Obliquus superior and Rectus externus, but in regard to the latter said that it is probable that it is developed from the walls of the dorsal ends of the 2nd and 3rd head-cavities.",
    url = "https://doi.org/10.1098/rstb.1929.0002",
    doi = "10.1098/rstb.1929.0002",
    openalex = "W2053133343"
}

@article{doi101152ajplegacy1931982296,
    author = "Smith, Homer W.",
    title = "THE ABSORPTION AND EXCRETION OF WATER AND SALTS BY THE ELASMOBRANCH FISHES",
    year = "1931",
    journal = "American Journal of Physiology-Legacy Content",
    url = "https://doi.org/10.1152/ajplegacy.1931.98.2.296",
    doi = "10.1152/ajplegacy.1931.98.2.296",
    openalex = "W3160275924"
}

Records of nearly 2000 dogfish collected from the Ilfracombe region suggest that the spawning season of this fish starts in November and continues at least until July. This area probably represents a spawning ground into which the females migrate during the spawning season; the males follow them much later in April and May. Figures are given to show the time taken at different temperatures for the embryo to develop to a series of definite morphological stages; these suggest that the temperature characteristic of the development (µ = 20,000) is substantially the same as for several teleost species.

@article{doi101017s002531540005298x,
    author = "Harris, John E.",
    title = "A note on the breeding season, sex ratio and embryonic development of the dogfish Scyliorhinus canicula (L.)",
    year = "1952",
    journal = "Journal of the Marine Biological Association of the United Kingdom",
    abstract = "Records of nearly 2000 dogfish collected from the Ilfracombe region suggest that the spawning season of this fish starts in November and continues at least until July. This area probably represents a spawning ground into which the females migrate during the spawning season; the males follow them much later in April and May. Figures are given to show the time taken at different temperatures for the embryo to develop to a series of definite morphological stages; these suggest that the temperature characteristic of the development (µ = 20,000) is substantially the same as for several teleost species.",
    url = "https://doi.org/10.1017/s002531540005298x",
    doi = "10.1017/s002531540005298x",
    openalex = "W2158514519"
}

Lillie's Development of the Chick Get access Lillie's Development of the Chick. Revised by Hamilton Howard L.. 624 pages, 283 figures. Henry Holt and Company, 383 Madison Avenue, New York 17, N. Y. (3rd edition, 1952) $8.50. AIBS Bulletin, Volume 3, Issue 1, January 1953, Page 15, https://doi.org/10.1093/aibsbulletin/3.1.15-f Published: 01 January 1953

@article{doi101093aibsbulletin3115f,
    title = "Lillie's Development of the Chick",
    year = "1953",
    journal = "AIBS Bulletin",
    abstract = "Lillie's Development of the Chick Get access Lillie's Development of the Chick. Revised by Hamilton Howard L.. 624 pages, 283 figures. Henry Holt and Company, 383 Madison Avenue, New York 17, N. Y. (3rd edition, 1952) $8.50. AIBS Bulletin, Volume 3, Issue 1, January 1953, Page 15, https://doi.org/10.1093/aibsbulletin/3.1.15-f Published: 01 January 1953",
    url = "https://doi.org/10.1093/aibsbulletin/3.1.15-f",
    doi = "10.1093/aibsbulletin/3.1.15-f",
    openalex = "W4240919262"
}

ABSTRACT Experiments with moving electrostatic and magnetic fields show that Gymnarchus niloticus is sensitive to a potential gradient of about 0 · 03 µ V./cm. Alternative explanations of some previous experiments are given in terms of this high d.c. sensitivity. An explanation in similar terms is given of experiments in which Gymnotus carapo is trained to detect a stationary magnet. The mechanisms available for the location of objects by electric fish are reviewed. It is concluded from the results of a critical experiment (described in a succeeding section) that Gymnarchus niloticus can detect objects by the disturbance of its own electric field in the water. The approximate theory of this method of object location is derived. The effect on the receptors of the perturbing field due to an object depends on the electrical properties of the receptors: in the extreme cases the stimulation of the receptors is proportional either to the potential or to its second derivative. Graphs are given showing the effect of an object on the potential and on its second derivative around the surface of the fish. Experiments are described using Gymnarchus niloticus which (a) confirm that the mechanism of object location employs electric field distortion; (i) indicate the limits of the sensitivity of the fish. The second derivative mode appears to be the most probable one operating in Gymnarchus. The experimentally determined limits of detection are discussed in relation to the random noise in the receptor circuit: it is concluded that both spatial and temporal integration are likely to be employed. The thresholds for object location and for response to direct currents are compared: it is concluded that the same receptors are probably operating in both cases.

@article{doi101242jeb352451,
    author = "Lissmann, H. W. and Machin, K. E.",
    title = "The Mechanism of Object Location in Gymnarchus Niloticus and Similar Fish",
    year = "1958",
    journal = "Journal of Experimental Biology",
    abstract = "ABSTRACT Experiments with moving electrostatic and magnetic fields show that Gymnarchus niloticus is sensitive to a potential gradient of about 0 · 03 µ V./cm. Alternative explanations of some previous experiments are given in terms of this high d.c. sensitivity. An explanation in similar terms is given of experiments in which Gymnotus carapo is trained to detect a stationary magnet. The mechanisms available for the location of objects by electric fish are reviewed. It is concluded from the results of a critical experiment (described in a succeeding section) that Gymnarchus niloticus can detect objects by the disturbance of its own electric field in the water. The approximate theory of this method of object location is derived. The effect on the receptors of the perturbing field due to an object depends on the electrical properties of the receptors: in the extreme cases the stimulation of the receptors is proportional either to the potential or to its second derivative. Graphs are given showing the effect of an object on the potential and on its second derivative around the surface of the fish. Experiments are described using Gymnarchus niloticus which (a) confirm that the mechanism of object location employs electric field distortion; (i) indicate the limits of the sensitivity of the fish. The second derivative mode appears to be the most probable one operating in Gymnarchus. The experimentally determined limits of detection are discussed in relation to the random noise in the receptor circuit: it is concluded that both spatial and temporal integration are likely to be employed. The thresholds for object location and for response to direct currents are compared: it is concluded that the same receptors are probably operating in both cases.",
    url = "https://doi.org/10.1242/jeb.35.2.451",
    doi = "10.1242/jeb.35.2.451",
    openalex = "W1957563271",
    references = "doi101007bf00340757, doi101016s0096417418301082, doi101016s0096417418301239, doi101038143960c0, doi101038167201a0, doi101152ajplegacy1917443405, lissmann1958on, openalexw3038515387"
}

The electric discharges of Gymnarchus niloticus and of representative species of seven genera of the Mormyridae have been examined in their natural habitat in Africa and in the laboratory. Comparable investigations of the South American Gymnotidae have shown the existence of two discharge types in both these unrelated fish families. The first type of electric discharge consists of very regular sequences of continuously emitted, monophasic pulses, varying from species to species in frequency, and within narrower limits from individual to individual. Fish emitting this first type of pulses include Gymnarchus, Hypopomus and Eigenmannia. The frequency range for these fish lies between 60 and 400 discharges/sec. The frequency does not alter with the state of excitation of the fish. The duration of individual pulses is relatively long, i.e. 2–10 msec. The second type of discharge is less regular in frequency, the pulse duration much shorter and the pulse shape more complex. The individual discharge from the whole electric organ lasts about 0.2 msec, in Petrocephalus. This type of discharge is found in all the examined species of the Mormyridae and in such forms as Gymnotus carapo and Staetogenes elegans. The basic discharge rate of a resting mormyrid is somewhat variable and not strictly rhythmical. It usually lies between 1 and 6 pulses/sec. Stimuli which excite the mormyrids cause an increase in the discharge frequency. The recorded maximum is about 130 pulses/sec. Suitable stimuli can inhibit the discharges of the Mormyridae for prolonged periods. In Gymnotus carapo and Staetogenes elegans the basic discharge rate is higher and of regular rhythmicity. Depending on temperature the frequencies lie between 30 and 87 pulses/sec. When these fish are excited the frequencies are increased up to 200 pulses/sec, for a short time. The shape of the electric field, which is set up with each pulse around the fish, has been examined. A theory has been proposed which suggests that these fish, by means of their electric pulses, can locate objects if their electrical conductivity differs from that of water. These fish have shown themselves extremely sensitive to influences affecting the electric field. This has been studied by applying artificial electric stimuli, by studying the effects of conductors and non-conductors introduced into the field, and the reactions towards magnetic fields and electrostatic charges. Conditioned reflex experiments with Gymnarchus niloticus and Gymnotus carapo have shown that these fish can detect the presence of a stationary magnet, and that they can discriminate between conductors and non-conductors. The prey of these fish does not appear to be affected by the discharges. Inter alia, the electric pulses have a social significance. This locating mechanism may be considered as an adaptation to life in turbid water. Gymnotidae and Mormyridae (taken to include Gymnarchus) show striking features of convergent evolution. Unusual locomotory adaptations such as swimming by means of the dorsal fin (Gymnarchus), the anal fin (Gymnotidae) and ‘Gemminger‘s bones’ (Mormyridae) may be considered as a means which tends to make the axis of symmetry of the fish and of its electric field coincide during active movements. A new theory for the evolution of electric organs has been suggested. A major prerequisite appears to be a receptor sensitive to electrical stimulation. It is suggested that special sensory and nervous differentiations of the lateralis system (‘mormyromasts’, valvulae cerebelli) are concerned with the perception and integration of electric stimuli. Muscular action potentials have been recorded in the water at some distance from non-electric fish. The easiest explanation for the evolution of strong electric organs would appear to start from such muscular action potentials, and proceed via weak electric organs used for orientation, to the powerful offensive and defensive electric organs."

@article{lissmann1958on,
    author = "Lissmann, H. W.",
    title = "On the Function and Evolution of Electric Organs in Fish",
    year = "1958",
    journal = "Journal of Experimental Biology",
    abstract = {The electric discharges of Gymnarchus niloticus and of representative species of seven genera of the Mormyridae have been examined in their natural habitat in Africa and in the laboratory. Comparable investigations of the South American Gymnotidae have shown the existence of two discharge types in both these unrelated fish families. The first type of electric discharge consists of very regular sequences of continuously emitted, monophasic pulses, varying from species to species in frequency, and within narrower limits from individual to individual. Fish emitting this first type of pulses include Gymnarchus, Hypopomus and Eigenmannia. The frequency range for these fish lies between 60 and 400 discharges/sec. The frequency does not alter with the state of excitation of the fish. The duration of individual pulses is relatively long, i.e. 2–10 msec. The second type of discharge is less regular in frequency, the pulse duration much shorter and the pulse shape more complex. The individual discharge from the whole electric organ lasts about 0.2 msec, in Petrocephalus. This type of discharge is found in all the examined species of the Mormyridae and in such forms as Gymnotus carapo and Staetogenes elegans. The basic discharge rate of a resting mormyrid is somewhat variable and not strictly rhythmical. It usually lies between 1 and 6 pulses/sec. Stimuli which excite the mormyrids cause an increase in the discharge frequency. The recorded maximum is about 130 pulses/sec. Suitable stimuli can inhibit the discharges of the Mormyridae for prolonged periods. In Gymnotus carapo and Staetogenes elegans the basic discharge rate is higher and of regular rhythmicity. Depending on temperature the frequencies lie between 30 and 87 pulses/sec. When these fish are excited the frequencies are increased up to 200 pulses/sec, for a short time. The shape of the electric field, which is set up with each pulse around the fish, has been examined. A theory has been proposed which suggests that these fish, by means of their electric pulses, can locate objects if their electrical conductivity differs from that of water. These fish have shown themselves extremely sensitive to influences affecting the electric field. This has been studied by applying artificial electric stimuli, by studying the effects of conductors and non-conductors introduced into the field, and the reactions towards magnetic fields and electrostatic charges. Conditioned reflex experiments with Gymnarchus niloticus and Gymnotus carapo have shown that these fish can detect the presence of a stationary magnet, and that they can discriminate between conductors and non-conductors. The prey of these fish does not appear to be affected by the discharges. Inter alia, the electric pulses have a social significance. This locating mechanism may be considered as an adaptation to life in turbid water. Gymnotidae and Mormyridae (taken to include Gymnarchus) show striking features of convergent evolution. Unusual locomotory adaptations such as swimming by means of the dorsal fin (Gymnarchus), the anal fin (Gymnotidae) and ‘Gemminger‘s bones’ (Mormyridae) may be considered as a means which tends to make the axis of symmetry of the fish and of its electric field coincide during active movements. A new theory for the evolution of electric organs has been suggested. A major prerequisite appears to be a receptor sensitive to electrical stimulation. It is suggested that special sensory and nervous differentiations of the lateralis system (‘mormyromasts’, valvulae cerebelli) are concerned with the perception and integration of electric stimuli. Muscular action potentials have been recorded in the water at some distance from non-electric fish. The easiest explanation for the evolution of strong electric organs would appear to start from such muscular action potentials, and proceed via weak electric organs used for orientation, to the powerful offensive and defensive electric organs."},
    url = "https://doi.org/10.1242/jeb.35.1.156",
    doi = "10.1242/jeb.35.1.156",
    number = "1",
    openalex = "W2287496592",
    pages = "156-191",
    volume = "35",
    references = "doi101002cne910110302, doi101017cbo9780511693281002, doi101038167201a0, doi10108000222931108692993, doi101098rspb19380041, doi101113jphysiol1952sp004695, doi101113jphysiol1953sp004849, doi1023071416035, doi1023072485224, doi105962bhltitle53990"
}

Fishes of the Western North Atlantic Get access Fishes of the Western North Atlantic, Memoir I, Part 5 by Anderson William W.et al., The Sears Foundation for Marine Research, New Haven, Conn., 1966. 647 pp. $27.50. BioScience, Volume 16, Issue 10, October 1966, Page 752, https://doi.org/10.1093/bioscience/16.10.752-a Published: 01 October 1966

@article{doi101093bioscience1610752a,
    title = "Fishes of the Western North Atlantic",
    year = "1966",
    journal = "BioScience",
    abstract = "Fishes of the Western North Atlantic Get access Fishes of the Western North Atlantic, Memoir I, Part 5 by Anderson William W.et al., The Sears Foundation for Marine Research, New Haven, Conn., 1966. 647 pp. $27.50. BioScience, Volume 16, Issue 10, October 1966, Page 752, https://doi.org/10.1093/bioscience/16.10.752-a Published: 01 October 1966",
    url = "https://doi.org/10.1093/bioscience/16.10.752-a",
    doi = "10.1093/bioscience/16.10.752-a",
    openalex = "W2260363390"
}

Abstract Annual fishes can maintain permanent populations in temporary aquatic habitats since the population survives dry seasons in the form of diapausing eggs. Populations persist even though subject to erratic environmental cycles and recurrent ecological catastrophes. Developmental arrest occurs at one or all of the following stages: Diapause I (Dispersed cell phase); Diapause II (Long somite embryo); Diapause III (Prehatching). In Austrofundulus, Diapause I is facultative. Diapause II and III are obligate, long and variable (105 ± 20 days each). Subpopulations (about 10%) of “escape eggs” bypass Diapause II and/or Diapause III. Pterolebias and Rachovia eggs behave much like those of Austrofundulus. In Rachovia, the duration of Diapause II is 80 ± 33 days and of Diapause III at least 61 ± 23 days. Subpopulations of “escape eggs” are present. Cynolebias and Nothobranchius can undergo facultative arrest at Diapause I and II and enter obligate arrest at Diapause III. Annual species of Aphyosemion can undergo facultative arrest at Diapause I and II, and an obligate arrest at Diapause III. A few species may also experience obligate arrest at Diapause II. A short term arrest phenomenon, “retarded hatching,” sometimes is encountered among non‐annual Aphyosemions and other non‐annual cyprinodonts. Survival strategy is based on the “multiplier effect”; i.e., interposition into the developmental pathway of three branch points containing diapause stages of prolonged, variable duration generates eight different distributions of total developmental time. Thus, a single egg population of identical age can generate several subpopulations, all of which develop according to different schedules. A developmental program is established which permits the repeated loss of individual eggs under conditions which may initiate hatching but do not allow for maturation and successful reproduction. The “multiplier effect” augmented by other adaptations guarantees that some portion of the egg population will survive to reproduce.

@article{doi101002jez1401820310,
    author = "Wourms, John P.",
    title = "The developmental biology of annual fishes. III. Pre‐embryonic and embryonic diapause of variable duration in the eggs of annual fishes",
    year = "1972",
    journal = "Journal of Experimental Zoology",
    abstract = "Abstract Annual fishes can maintain permanent populations in temporary aquatic habitats since the population survives dry seasons in the form of diapausing eggs. Populations persist even though subject to erratic environmental cycles and recurrent ecological catastrophes. Developmental arrest occurs at one or all of the following stages: Diapause I (Dispersed cell phase); Diapause II (Long somite embryo); Diapause III (Prehatching). In Austrofundulus, Diapause I is facultative. Diapause II and III are obligate, long and variable (105 ± 20 days each). Subpopulations (about 10\%) of “escape eggs” bypass Diapause II and/or Diapause III. Pterolebias and Rachovia eggs behave much like those of Austrofundulus. In Rachovia, the duration of Diapause II is 80 ± 33 days and of Diapause III at least 61 ± 23 days. Subpopulations of “escape eggs” are present. Cynolebias and Nothobranchius can undergo facultative arrest at Diapause I and II and enter obligate arrest at Diapause III. Annual species of Aphyosemion can undergo facultative arrest at Diapause I and II, and an obligate arrest at Diapause III. A few species may also experience obligate arrest at Diapause II. A short term arrest phenomenon, “retarded hatching,” sometimes is encountered among non‐annual Aphyosemions and other non‐annual cyprinodonts. Survival strategy is based on the “multiplier effect”; i.e., interposition into the developmental pathway of three branch points containing diapause stages of prolonged, variable duration generates eight different distributions of total developmental time. Thus, a single egg population of identical age can generate several subpopulations, all of which develop according to different schedules. A developmental program is established which permits the repeated loss of individual eggs under conditions which may initiate hatching but do not allow for maturation and successful reproduction. The “multiplier effect” augmented by other adaptations guarantees that some portion of the egg population will survive to reproduce.",
    url = "https://doi.org/10.1002/jez.1401820310",
    doi = "10.1002/jez.1401820310",
    openalex = "W2107973522",
    references = "doi105694j132653771943tb44800x"
}

The emergence of efficient ecosystem modelling is severely hampered by the need for an ecological classification of fishes. An earlier concept of ecological groups is here expanded to cover all living fishes. This ecological classification is based mainly on form and function in early developmental intervals, on preferred spawning grounds, and on features of reproductive behavior. Within the adaptations for reproduction and embryonic development two factors prevail — predators and the oxygen regime; consequently, spawning behavior and spawning grounds determine ensuing respiratory conditions and available protection from predators. The remaining factors are more or less associated with those two. From the point of view of resource exploitation, factors other than feeding habits governing density, biomass, and production are more important. In this sense reproductive guilds are more meaningful than feeding strategies, to which one usage of "guild" was limited.Thirty-two guilds putatively encompass all the 30,000 living fish taxa (or about 20,000 species) and form an ecological classification unrelated to the Linnean classification. The guilds retain phyletic significance in respect to reproductive systems and form a basis for the construction of models on natural and cultural succession. Number of guilds and frequency of taxa within guilds in a given area reflect geochronological sequences and invasion abilities of members of different guilds.

@article{doi101139f75110,
    author = "Balon, Eugene K.",
    title = "Reproductive Guilds of Fishes: A Proposal and Definition",
    year = "1975",
    journal = "Journal of the Fisheries Research Board of Canada",
    abstract = {The emergence of efficient ecosystem modelling is severely hampered by the need for an ecological classification of fishes. An earlier concept of ecological groups is here expanded to cover all living fishes. This ecological classification is based mainly on form and function in early developmental intervals, on preferred spawning grounds, and on features of reproductive behavior. Within the adaptations for reproduction and embryonic development two factors prevail — predators and the oxygen regime; consequently, spawning behavior and spawning grounds determine ensuing respiratory conditions and available protection from predators. The remaining factors are more or less associated with those two. From the point of view of resource exploitation, factors other than feeding habits governing density, biomass, and production are more important. In this sense reproductive guilds are more meaningful than feeding strategies, to which one usage of "guild" was limited.Thirty-two guilds putatively encompass all the 30,000 living fish taxa (or about 20,000 species) and form an ecological classification unrelated to the Linnean classification. The guilds retain phyletic significance in respect to reproductive systems and form a basis for the construction of models on natural and cultural succession. Number of guilds and frequency of taxa within guilds in a given area reflect geochronological sequences and invasion abilities of members of different guilds.},
    url = "https://doi.org/10.1139/f75-110",
    doi = "10.1139/f75-110",
    openalex = "W2149718280"
}

Patterns of chondrichthyan reproduction and development are diverse. Species either are reproductively active throughout the year, or have a poorly defined annual cycle with one or two peaks of activity, or have a well defined annual or biennial cycle. Based on embryological origin and adult morphology, their reproductive system is more similar to tetrapods than to teleosts. Primordial germ cells are of endodermal origin. The Wolffian ducts in males and Mullerian ducts in females become the functional urogenital ducts. Differentiation is under hormonal control. Unusual features of the reproductive system include an epigonal organ in males and females. It contains lymphoid and hemopoietic tissue. Leydig's gland, a modified region of the kidney, produces seminal fluid. In some species, sperm passing through the vas deferens, is enclosed in spermatophores. Rotating about their long axis, helical spermatozoa can move forward or reverse direction. Spermatogenesis often occurs in bicellular units, spermatocysts. These consist of a spermatogonium enclosed in a Sertoh cell. Fertilization is internal. Claspers, modified portions of the pelvic fins act as intromittent organs. In many viviparous sharks and rays, the female reproductive system is asymmetrical. Eggs of some sharks are the largest known cells. Yolk platelets contain lipovitellin. Oocytes have lampbrush chromosomes. Eggs released from the ovary into the body cavity are transported by ciliary action to the ostium of the oviduct. There they are fertilized. Physiological polyspermy is normal. The shell gland, a specialized region of the anterior oviduct, functions both in long term sperm storage and in egg case production. Egg cases of sharks and skates consist of unique collagenous protein with a 400 Å period, organized as a cholesteric liquid crystal. Chimaeroid egg cases contain 550 Å pseudotubules in orthogonal lattices. In small sharks, males copulate by coiling around the female. A parallel position is assumed by large sharks. Skates and rays copulate with ventral surfaces apposed or by a dorsal approach. Biting is a pre-copulatory release mechanism. Parental care, except for selective oviposition, is lacking. Heavily yolked eggs undergo meroblastic, discoidal cleavage. Development is lengthy, shortest (2–4 months) in rays, longer in skates (3–8 months) and longest (9–22 months) in sharks and chimaeras. Most sharks and all rays are viviparous. Chimaeras, skates, and some sharks are oviparous. Viviparity either involves a yolk sac placenta or is aplacental. If aplacental, the embryo derives nutrients either from yolk reserves, or by intra-uterine embryonic cannibalism, or from placental analogues which secrete “uterine milk.” Phylogenetic position, geographical distribution, benthic vs. pelagic habitat, adult size, egg-embryo size, feeding ecology, and embryonic osmoregulation are factors in the retention of oviparity or the evolution of viviparity.

@article{doi101093icb172379,
    author = "Wourms, John P.",
    title = "Reproduction and Development in Chondrichthyan Fishes",
    year = "1977",
    journal = "American Zoologist",
    abstract = "Patterns of chondrichthyan reproduction and development are diverse. Species either are reproductively active throughout the year, or have a poorly defined annual cycle with one or two peaks of activity, or have a well defined annual or biennial cycle. Based on embryological origin and adult morphology, their reproductive system is more similar to tetrapods than to teleosts. Primordial germ cells are of endodermal origin. The Wolffian ducts in males and Mullerian ducts in females become the functional urogenital ducts. Differentiation is under hormonal control. Unusual features of the reproductive system include an epigonal organ in males and females. It contains lymphoid and hemopoietic tissue. Leydig's gland, a modified region of the kidney, produces seminal fluid. In some species, sperm passing through the vas deferens, is enclosed in spermatophores. Rotating about their long axis, helical spermatozoa can move forward or reverse direction. Spermatogenesis often occurs in bicellular units, spermatocysts. These consist of a spermatogonium enclosed in a Sertoh cell. Fertilization is internal. Claspers, modified portions of the pelvic fins act as intromittent organs. In many viviparous sharks and rays, the female reproductive system is asymmetrical. Eggs of some sharks are the largest known cells. Yolk platelets contain lipovitellin. Oocytes have lampbrush chromosomes. Eggs released from the ovary into the body cavity are transported by ciliary action to the ostium of the oviduct. There they are fertilized. Physiological polyspermy is normal. The shell gland, a specialized region of the anterior oviduct, functions both in long term sperm storage and in egg case production. Egg cases of sharks and skates consist of unique collagenous protein with a 400 Å period, organized as a cholesteric liquid crystal. Chimaeroid egg cases contain 550 Å pseudotubules in orthogonal lattices. In small sharks, males copulate by coiling around the female. A parallel position is assumed by large sharks. Skates and rays copulate with ventral surfaces apposed or by a dorsal approach. Biting is a pre-copulatory release mechanism. Parental care, except for selective oviposition, is lacking. Heavily yolked eggs undergo meroblastic, discoidal cleavage. Development is lengthy, shortest (2–4 months) in rays, longer in skates (3–8 months) and longest (9–22 months) in sharks and chimaeras. Most sharks and all rays are viviparous. Chimaeras, skates, and some sharks are oviparous. Viviparity either involves a yolk sac placenta or is aplacental. If aplacental, the embryo derives nutrients either from yolk reserves, or by intra-uterine embryonic cannibalism, or from placental analogues which secrete “uterine milk.” Phylogenetic position, geographical distribution, benthic vs. pelagic habitat, adult size, egg-embryo size, feeding ecology, and embryonic osmoregulation are factors in the retention of oviparity or the evolution of viviparity.",
    url = "https://doi.org/10.1093/icb/17.2.379",
    doi = "10.1093/icb/17.2.379",
    openalex = "W2113575423",
    references = "doi101016b9780122825019500065, doi101086282063, doi101093bioscience1610752a, doi101093icb172365, doi1010970000505319311100000026, doi101111j1469185x1936tb00497x, doi1023073221988, doi105694j132653771943tb44800x, openalexw3026020306, openalexw612600151"
}

Serial sections ranging from very young embryos to hatched juveniles and whole embryos of Scyliorhinus show that dentition and dermal skeleton belong to two independent secondary developmental fields that differ both developmentally and structurally. The development of the dentition starts very early, with a thickening of the ectoderm in the region of the mouth (stage 04), the invagination of the dental lamina (stage 18), and the formation of the germs of the first generation (stage 20). Tooth replacement movements start only near the end of embryogenesis (stage 35). Scale germs, on the other hand, first begin to form at stage 24. Scales erupt shortly before the animal hatches (stage 43). Only one scale generation is formed during embryogenesis. The forces which erupt the scales may come from fluid pressures in vacuoles of the fibrous layer of the dermis. Those which erupt the teeth probably also result from similar fluid pressures. The crown and upper part of the base of scales and teeth are formed by cells of the inner dental epithelium which are differentiated from the ectoderm. They are also formed by odontoblasts which are derived from the vascular layer of the dermis. However, the basal plates of scales and teeth containing the anchoring fibers are formed by osteoblasts, which are derived from the fibrous layer of the dermis.

@article{doi101002jmor1051660303,
    author = "Reif, Wolf‐Ernst",
    title = "Development of dentition and dermal skeleton in embryonic Scyliorhinus canicula",
    year = "1980",
    journal = "Journal of Morphology",
    abstract = "Serial sections ranging from very young embryos to hatched juveniles and whole embryos of Scyliorhinus show that dentition and dermal skeleton belong to two independent secondary developmental fields that differ both developmentally and structurally. The development of the dentition starts very early, with a thickening of the ectoderm in the region of the mouth (stage 04), the invagination of the dental lamina (stage 18), and the formation of the germs of the first generation (stage 20). Tooth replacement movements start only near the end of embryogenesis (stage 35). Scale germs, on the other hand, first begin to form at stage 24. Scales erupt shortly before the animal hatches (stage 43). Only one scale generation is formed during embryogenesis. The forces which erupt the scales may come from fluid pressures in vacuoles of the fibrous layer of the dermis. Those which erupt the teeth probably also result from similar fluid pressures. The crown and upper part of the base of scales and teeth are formed by cells of the inner dental epithelium which are differentiated from the ectoderm. They are also formed by odontoblasts which are derived from the vascular layer of the dermis. However, the basal plates of scales and teeth containing the anchoring fibers are formed by osteoblasts, which are derived from the fibrous layer of the dermis.",
    url = "https://doi.org/10.1002/jmor.1051660303",
    doi = "10.1002/jmor.1051660303",
    openalex = "W2059396035",
    references = "balfour1878a, doi101002jmor1051330103, doi101007bf00995429, doi101007bf02568678, doi101007bf03006733, doi101111j146363951940tb00339x, doi101126science948762, doi1016690883135120010160418br20co2, doi105962bhltitle7847, openalexw115975037, openalexw2042807370"
}

In this paper the stimuli for and pattern of Schwann cell proliferation are defined under various experimental conditions. We used a tissue culture system in which fetal rat dorsal root ganglia, treated to eliminate contaminating fibroblasts (Wood, P., 1976, Brain Res. 115:361--375), appear to recapitulate many aspects of the developing peripheral nervous system. We observed that: (a) proliferation of Schwann cells on neurites is initially rapid, but, as each neurite becomes fully ensheathed, division slows considerably and is confined to the periphery of the outgrowth; (b) during the period of rapid proliferation, excision of the ganglion causes a rapid decay in the number of dividing cells; (c) excision of the ganglion from more established cultures in which there was little ongoing proliferation resulted in a small increase in labeling at the site of excision for all Schwann cells and a substantial increase in labeling for myelin-related cells with a peak labeling period at 4 d; (d) direct mechanical injury during Wallerian degeneration is mitogenic for Schwann cells; (e) a variety of potential mitogens failed to stimulate Schwann cell proliferation, and (f) replated cells have a slightly higher level of proliferation and show a small and variable response to the addition of cAMP.

@article{doi101083jcb843739,
    author = "Salzer, James L. and Bunge, R P",
    title = "Studies of Schwann cell proliferation. I. An analysis in tissue culture of proliferation during development, Wallerian degeneration, and direct injury.",
    year = "1980",
    journal = "The Journal of Cell Biology",
    abstract = "In this paper the stimuli for and pattern of Schwann cell proliferation are defined under various experimental conditions. We used a tissue culture system in which fetal rat dorsal root ganglia, treated to eliminate contaminating fibroblasts (Wood, P., 1976, Brain Res. 115:361--375), appear to recapitulate many aspects of the developing peripheral nervous system. We observed that: (a) proliferation of Schwann cells on neurites is initially rapid, but, as each neurite becomes fully ensheathed, division slows considerably and is confined to the periphery of the outgrowth; (b) during the period of rapid proliferation, excision of the ganglion causes a rapid decay in the number of dividing cells; (c) excision of the ganglion from more established cultures in which there was little ongoing proliferation resulted in a small increase in labeling at the site of excision for all Schwann cells and a substantial increase in labeling for myelin-related cells with a peak labeling period at 4 d; (d) direct mechanical injury during Wallerian degeneration is mitogenic for Schwann cells; (e) a variety of potential mitogens failed to stimulate Schwann cell proliferation, and (f) replated cells have a slightly higher level of proliferation and show a small and variable response to the addition of cAMP.",
    url = "https://doi.org/10.1083/jcb.84.3.739",
    doi = "10.1083/jcb.84.3.739",
    openalex = "W2047909489",
    references = "doi101002cne900370107"
}

well as an osmotic distension of the egg envelopes. The perivitelline fluid and its containing multilamellar envelopes with their varied specialized patterns and filamentous elaborations provide a number of protective, nutritive, flotative, polyspermy preventive and regulative functions. Fish eggs and embryos, by monitoring the immediate environment, possibly may modify the colloidal composition of the perivitelline fluid and the substructural organization of the egg envelopes in some instances, thus providing an adaptive mechanism for survival in a polluted environment. The review includes a discussion of the problematic issues surrounding membrane origin, structure and nomenclature, suggestions for further research and an extensive bibliography.

@article{doi1023071443999,
    author = "Laale, Hans W.",
    title = "The Perivitelline Space and Egg Envelopes of Bony Fishes: A Review",
    year = "1980",
    journal = "Copeia",
    abstract = "well as an osmotic distension of the egg envelopes. The perivitelline fluid and its containing multilamellar envelopes with their varied specialized patterns and filamentous elaborations provide a number of protective, nutritive, flotative, polyspermy preventive and regulative functions. Fish eggs and embryos, by monitoring the immediate environment, possibly may modify the colloidal composition of the perivitelline fluid and the substructural organization of the egg envelopes in some instances, thus providing an adaptive mechanism for survival in a polluted environment. The review includes a discussion of the problematic issues surrounding membrane origin, structure and nomenclature, suggestions for further research and an extensive bibliography.",
    url = "https://doi.org/10.2307/1443999",
    doi = "10.2307/1443999",
    openalex = "W2312771443",
    references = "doi101002ar1090680102, doi101002jez1401820202, doi101002jez1401840103, doi101016s1546509808600850, doi101016s1546509808601144, doi101242dev63373, doi1023071539545, openalexw285943563, openalexw612600151, openalexw654064239"
}

SYNOPSIS. Viviparity in the vertebrate line first makes its evolutionary appearance among fishes. It has independently evolved in a number of divergent piscine lineages. The 54 families of extant fishes that bear living young include 40 families of chondrichthyans (sharks and rays), one montypic family of coelacanths (Latimeria), and 13 families of teleosts. There is fossil evidence for viviparity in holocephalans and chondrosteans. Viviparity predominates among sharks and rays (40 families, 99 genera, 420 species) but is less widespread among teleosts (13 families, 122 genera, 510 species). Following an historical introduction, the organization of the female reproductive system, sites of gestation, developmental sequences and superfetation are considered. The evolution of viviparity establishes specialized maternal-fetal relationships, viz., 1) developmental, 2) morphological, 3) trophic, 4) osmoregulatory, 5) respiratory, 6) endocrinological, and 7) immunological. While the latter four categories are briefly noted the major emphasis is on the trophic relationship and its morphological and developmental basis. First, a general overview is presented and then the maternal-fetal trophic relationships in each of the major groups of fishes are systematically reviewed. Pertinent anatomical, histological, ultrastructural, developmental, physiological, and biochemical studies are considered. Viviparous fishes are either lecithotrophic, i.e., exclusively yolk dependent, or matrotrophic, i.e., in receipt of a continuous supply of maternal nutrients during gestation. Nutrient transfer is accomplished by 1) oophagy and adelphophagy, 2) placental analogues, and 3) the yolk sac placenta. Placental analogues include: external epithelial absorptive surfaces, e.g., skin, fins, gills; trophonemata, modifications of the uterine epithelia for the secretion of histotrophe or “uterine milk”; branchial placentae, close apposition between gill epithelia and either uterine or ovarian epithelial villi; the yolk sac; pericardial amnion and chorion; follicular pseudoplacenta, close apposition between follicle cells and embryonic absorptive epithelia; hypertrophied gut; and trophotaeniae, external rosette or ribbon-like projections of the embryonic gut. Among chondrichthyans, the yolk sac placenta (840–1,050%), trophonematal secretion and embryonic absorbtion of histotrophe (1,680–4,900%) and oophagy and adelphophagy (1.2 × 106%) are the most efficient methods of nutrient transfer. Among teleosts, the follicular pseudoplacenta (1,800–3,900%), trophotaeniae (8,400%) and absorption of ovarian histotrophe through surface epithelia and a hypertrophied gut (1,100–34,000%) are the most efficient. These values stand in contrast to the 30%40% loss of dry weight characteristic of oviparous fishes and viviparous lecithotrophes.

@article{doi101093icb212473,
    author = "Wourms, John P.",
    title = "Viviparity: The Maternal-Fetal Relationship in Fishes",
    year = "1981",
    journal = "American Zoologist",
    abstract = "SYNOPSIS. Viviparity in the vertebrate line first makes its evolutionary appearance among fishes. It has independently evolved in a number of divergent piscine lineages. The 54 families of extant fishes that bear living young include 40 families of chondrichthyans (sharks and rays), one montypic family of coelacanths (Latimeria), and 13 families of teleosts. There is fossil evidence for viviparity in holocephalans and chondrosteans. Viviparity predominates among sharks and rays (40 families, 99 genera, 420 species) but is less widespread among teleosts (13 families, 122 genera, 510 species). Following an historical introduction, the organization of the female reproductive system, sites of gestation, developmental sequences and superfetation are considered. The evolution of viviparity establishes specialized maternal-fetal relationships, viz., 1) developmental, 2) morphological, 3) trophic, 4) osmoregulatory, 5) respiratory, 6) endocrinological, and 7) immunological. While the latter four categories are briefly noted the major emphasis is on the trophic relationship and its morphological and developmental basis. First, a general overview is presented and then the maternal-fetal trophic relationships in each of the major groups of fishes are systematically reviewed. Pertinent anatomical, histological, ultrastructural, developmental, physiological, and biochemical studies are considered. Viviparous fishes are either lecithotrophic, i.e., exclusively yolk dependent, or matrotrophic, i.e., in receipt of a continuous supply of maternal nutrients during gestation. Nutrient transfer is accomplished by 1) oophagy and adelphophagy, 2) placental analogues, and 3) the yolk sac placenta. Placental analogues include: external epithelial absorptive surfaces, e.g., skin, fins, gills; trophonemata, modifications of the uterine epithelia for the secretion of histotrophe or “uterine milk”; branchial placentae, close apposition between gill epithelia and either uterine or ovarian epithelial villi; the yolk sac; pericardial amnion and chorion; follicular pseudoplacenta, close apposition between follicle cells and embryonic absorptive epithelia; hypertrophied gut; and trophotaeniae, external rosette or ribbon-like projections of the embryonic gut. Among chondrichthyans, the yolk sac placenta (840–1,050\%), trophonematal secretion and embryonic absorbtion of histotrophe (1,680–4,900\%) and oophagy and adelphophagy (1.2 × 106\%) are the most efficient methods of nutrient transfer. Among teleosts, the follicular pseudoplacenta (1,800–3,900\%), trophotaeniae (8,400\%) and absorption of ovarian histotrophe through surface epithelia and a hypertrophied gut (1,100–34,000\%) are the most efficient. These values stand in contrast to the 30\%40\% loss of dry weight characteristic of oviparous fishes and viviparous lecithotrophes.",
    url = "https://doi.org/10.1093/icb/21.2.473",
    doi = "10.1093/icb/21.2.473",
    openalex = "W2062820559",
    references = "doi101093icb172303, doi101098rspb19800052, doi101126science19042191105, doi105694j132653771943tb44800x, openalexw2954279587, openalexw563680134"
}

Sharks, skates, and rays receive electrical information about the positions of their prey, the drift of ocean currents, and their magnetic compass headings. At sea, dogfish and blue sharks were observed to execute apparent feeding responses to dipole electric fields designed to mimic prey. In training experiments, stingrays showed the ability to orient relative to uniform electric fields similar to those produced by ocean currents. Voltage gradients of only 5 nanovolts per centimeter would elicit either behavior.

@article{doi101126science7134985,
    author = "Kalmijn, Ad. J.",
    title = "Electric and Magnetic Field Detection in Elasmobranch Fishes",
    year = "1982",
    journal = "Science",
    abstract = "Sharks, skates, and rays receive electrical information about the positions of their prey, the drift of ocean currents, and their magnetic compass headings. At sea, dogfish and blue sharks were observed to execute apparent feeding responses to dipole electric fields designed to mimic prey. In training experiments, stingrays showed the ability to orient relative to uniform electric fields similar to those produced by ocean currents. Voltage gradients of only 5 nanovolts per centimeter would elicit either behavior.",
    url = "https://doi.org/10.1126/science.7134985",
    doi = "10.1126/science.7134985",
    openalex = "W1967128502",
    references = "doi101242jeb552371"
}

Serial sections of 105 human embryos (including 20 silver preparations) from stage 11 (24 days) to stage 22 (54 days) were studied, and 23 graphic reconstructions were prepared. The hypoglossal nucleus is evident at stage 12 and becomes isolated from other efferent nuclei at stage 14. The first hypoglossal nerve fibers appear at stage 12. The roots unite at stage 14 and the main trunk arrives in the tongue at stage 15. Four occipital somites can be identified during stage 13, and the sclerotomic material forms two bilateral masses. The fourth sclerotome separates in stage 14 and develops like a vertebra. This and the remaining sclerotomic material form the basioccipital and exoccipital parts of the chondrocranium, which are the first to appear. Four occipital myotomes develop and grow towards the tongue as the "hypoglossal cord", which arrives prior to the hypoglossal nerve. The developmental similarity in the hypoglossal region between birds and mammals, combined with experimental studies in birds, renders it extremely likely that the hypoglossal musculature in mammals also is derived from occipital somites. The present study is the first in which this conclusion is adequately supported in the human. This investigation aids in the interpretation and timing of origin of variations (e.g., bipartite hypoglossal canal) and anomalies (e.g., persistent hypoglossal artery).

@article{doi101002aja1001690302,
    author = "O’Rahilly, Ronan and Müller, Fabiola",
    title = "The early development of the hypoglossal nerve and occipital somites in staged human embryos",
    year = "1984",
    journal = "American Journal of Anatomy",
    abstract = {Serial sections of 105 human embryos (including 20 silver preparations) from stage 11 (24 days) to stage 22 (54 days) were studied, and 23 graphic reconstructions were prepared. The hypoglossal nucleus is evident at stage 12 and becomes isolated from other efferent nuclei at stage 14. The first hypoglossal nerve fibers appear at stage 12. The roots unite at stage 14 and the main trunk arrives in the tongue at stage 15. Four occipital somites can be identified during stage 13, and the sclerotomic material forms two bilateral masses. The fourth sclerotome separates in stage 14 and develops like a vertebra. This and the remaining sclerotomic material form the basioccipital and exoccipital parts of the chondrocranium, which are the first to appear. Four occipital myotomes develop and grow towards the tongue as the "hypoglossal cord", which arrives prior to the hypoglossal nerve. The developmental similarity in the hypoglossal region between birds and mammals, combined with experimental studies in birds, renders it extremely likely that the hypoglossal musculature in mammals also is derived from occipital somites. The present study is the first in which this conclusion is adequately supported in the human. This investigation aids in the interpretation and timing of origin of variations (e.g., bipartite hypoglossal canal) and anomalies (e.g., persistent hypoglossal artery).},
    url = "https://doi.org/10.1002/aja.1001690302",
    doi = "10.1002/aja.1001690302",
    openalex = "W2107288999",
    references = "doi101002aja1000040106"
}

The quality of parental care appears to correlate positively with egg size, both among and within species of fishes. Past models of the trade-off between quantity and quality of offspring have been inadequate in explaining this correlation. Using features of models by Smith and Fretwell (1974), Shine (1978), and Taylor and Williams (1984), we constructed a model to explain continuous covariation between the quality of parental care and egg size. Our model contains three major assumptions about the dependence of offspring survival on egg size: offspring from larger eggs develop more slowly and take longer to resorb their yolk sacs and become juveniles; egg size determines initial juvenile size; and larger juveniles, which hatch from larger eggs, have lower mortalities, experience faster growth, and take less time to become adults. Under these assumptions, as parental care reduces instantaneous egg mortality, the optimal egg size increases. This increase is expected both among and within populations. Thus, the general conclusion that each population should have a single optimal egg size (see, e.g., Smith and Fretwell 1974; Maynard Smith 1978) may be incorrect.

@article{doi101086284621,
    author = "Sargent, Robert Craig and Taylor, Peter and Gross, Mart R.",
    title = "Parental Care and the Evolution of Egg Size in Fishes",
    year = "1987",
    journal = "The American Naturalist",
    abstract = "The quality of parental care appears to correlate positively with egg size, both among and within species of fishes. Past models of the trade-off between quantity and quality of offspring have been inadequate in explaining this correlation. Using features of models by Smith and Fretwell (1974), Shine (1978), and Taylor and Williams (1984), we constructed a model to explain continuous covariation between the quality of parental care and egg size. Our model contains three major assumptions about the dependence of offspring survival on egg size: offspring from larger eggs develop more slowly and take longer to resorb their yolk sacs and become juveniles; egg size determines initial juvenile size; and larger juveniles, which hatch from larger eggs, have lower mortalities, experience faster growth, and take less time to become adults. Under these assumptions, as parental care reduces instantaneous egg mortality, the optimal egg size increases. This increase is expected both among and within populations. Thus, the general conclusion that each population should have a single optimal egg size (see, e.g., Smith and Fretwell 1974; Maynard Smith 1978) may be incorrect.",
    url = "https://doi.org/10.1086/284621",
    doi = "10.1086/284621",
    openalex = "W1999772799",
    references = "doi1010160022519372900070, doi101016s1546509808600345, doi101017cbo9781139167826, doi101086282929, doi101086283037, doi101086284325, doi101093icb172379, doi101093icb253807, doi101093icesjms282211, doi1023071937508"
}

This review deals with the following seven aspects of vertebrate skeletogenic and odontogenic tissues. 1. The evolutionary sequence in which the tissues appeared amongst the lower craniate taxa. 2. The topographic association between skeletal (cartilage, bone) and dental (dentine, cement, enamel) tissues in the oldest vertebrates of each major taxon. 3. The separate developmental origin of the exo- and endoskeletons. 4. The neural-crest origin of cranial skeletogenic and odontogenic tissues in extant vertebrates. 5. The neural-crest origin of trunk dermal skeletogenic and odontogenic tissues in extant vertebrates. 6. The developmental processes that control differentiation of skeletogenic and odontogenic tissues in extant vertebrates. 7. Maintenance of developmental interactions regulating skeletogenic/odontogenic differentiation across vertebrate taxa. We derive twelve postulates, eight relating to the earliest vertebrate skeletogenic and odontogenic tissues and four relating to the development of these tissues in extant vertebrates and extrapolate the developmental data back to the evolutionary origin of vertebrate skeletogenic and odontogenic tissues. The conclusions that we draw from this analysis are as follows. 8. The dermal exoskeleton of thelodonts, heterostracans and osteostracans consisted of dentine, attachment tissue (cement or bone), and bone. 9. Cartilage (unmineralized) can be inferred to have been present in heterostracans and osteostracans, and globular mineralized cartilage was present in Eriptychius, an early Middle Ordovician vertebrate unassigned to any established group, but assumed to be a stem agnathan. 10. Enamel and possibly also enameloid was present in some early agnathans of uncertain affinities. The majority of dentine tubercles were bare. 11. The contemporaneous appearance of cellular and acellular bone in heterostracans and osteostracans during the Ordovician provides no clue as to whether one is more primitive than the other. 12. We interpret aspidin as being developmentally related to the odontogenic attachment tissues, either closer to dentine or a form of cement, rather than as derived from bone. 13. Dentine is present in the stratigraphically oldest (Cambrian) assumed vertebrate fossils, at present some only included as Problematica, and is cladistically primitive, relative to bone. 14. The first vertebrate exoskeletal skeletogenic ability was expressed as denticles of dentine. 15. Dentine, the bone of attachment associated with dentine, the basal bone to which dermal denticles are fused and cartilage of the Ordovician agnathan dermal exoskeleton were all derived from the neural crest and not from mesoderm. Therefore the earliest vertebrate skeletogenic/odontogenic tissues were of neural-crest origin.(ABSTRACT TRUNCATED AT 400 WORDS)

@article{doi101111j1469185x1990tb01427x,
    author = "Smith, Moya Meredith and Hall, Brian K.",
    title = "DEVELOPMENT AND EVOLUTIONARY ORIGINS OF VERTEBRATE SKELETOGENIC AND ODONTOGENIC TISSUES",
    year = "1990",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "This review deals with the following seven aspects of vertebrate skeletogenic and odontogenic tissues. 1. The evolutionary sequence in which the tissues appeared amongst the lower craniate taxa. 2. The topographic association between skeletal (cartilage, bone) and dental (dentine, cement, enamel) tissues in the oldest vertebrates of each major taxon. 3. The separate developmental origin of the exo- and endoskeletons. 4. The neural-crest origin of cranial skeletogenic and odontogenic tissues in extant vertebrates. 5. The neural-crest origin of trunk dermal skeletogenic and odontogenic tissues in extant vertebrates. 6. The developmental processes that control differentiation of skeletogenic and odontogenic tissues in extant vertebrates. 7. Maintenance of developmental interactions regulating skeletogenic/odontogenic differentiation across vertebrate taxa. We derive twelve postulates, eight relating to the earliest vertebrate skeletogenic and odontogenic tissues and four relating to the development of these tissues in extant vertebrates and extrapolate the developmental data back to the evolutionary origin of vertebrate skeletogenic and odontogenic tissues. The conclusions that we draw from this analysis are as follows. 8. The dermal exoskeleton of thelodonts, heterostracans and osteostracans consisted of dentine, attachment tissue (cement or bone), and bone. 9. Cartilage (unmineralized) can be inferred to have been present in heterostracans and osteostracans, and globular mineralized cartilage was present in Eriptychius, an early Middle Ordovician vertebrate unassigned to any established group, but assumed to be a stem agnathan. 10. Enamel and possibly also enameloid was present in some early agnathans of uncertain affinities. The majority of dentine tubercles were bare. 11. The contemporaneous appearance of cellular and acellular bone in heterostracans and osteostracans during the Ordovician provides no clue as to whether one is more primitive than the other. 12. We interpret aspidin as being developmentally related to the odontogenic attachment tissues, either closer to dentine or a form of cement, rather than as derived from bone. 13. Dentine is present in the stratigraphically oldest (Cambrian) assumed vertebrate fossils, at present some only included as Problematica, and is cladistically primitive, relative to bone. 14. The first vertebrate exoskeletal skeletogenic ability was expressed as denticles of dentine. 15. Dentine, the bone of attachment associated with dentine, the basal bone to which dermal denticles are fused and cartilage of the Ordovician agnathan dermal exoskeleton were all derived from the neural crest and not from mesoderm. Therefore the earliest vertebrate skeletogenic/odontogenic tissues were of neural-crest origin.(ABSTRACT TRUNCATED AT 400 WORDS)",
    url = "https://doi.org/10.1111/j.1469-185x.1990.tb01427.x",
    doi = "10.1111/j.1469-185x.1990.tb01427.x",
    openalex = "W2104126911",
    references = "doi10100797814615696887, doi101007bf02058654, doi1010160012160683903184, doi101017cbo9780511897948, doi101017s0016756800082856, doi101017s0080456800035237, doi101038282831a0, doi101038282833a0, doi101038scientificamerican0779122, doi10108002724634198110011886, doi10108002724634198410012014, doi101086413055, doi101093aesa323657, doi101111j109636421986tb00876x, doi101111j146363951940tb00339x, doi101111j146364091979tb00640x, doi101111j146364091980tb00660x, doi101111j1469185x1973tb01005x, doi101111j150239311983tb01993x, doi101111j150239311986tb00741x, doi101126science15737951472, doi101126science2204594268, doi101130gsab3153, doi1023072413259, doi1023072413454, doi1023072992444, doi105962bhltitle5752, doi105962bhltitle82144, halstead1969calcified, halstead1979agnathans, openalexw115975037, openalexw251296685, openalexw2591687711, openalexw2732375649, openalexw587905045"
}

Abstract A large sample of embryological material of the North American paddlefish Polyodon spathula (Acipenseriformes: Polyodontidae) confirms that early development in Polyodon is very similar to that reported for the sister group of Polyodontidae, the sturgeons (Acipenseridae). Polyodon illustrates many basic aspects of acipenseriform (and actinopterygian) head development that have not been adequately described. In this paper, we provide an overview of external features of cranial development using scanning electron microscopy. The observations are correlated with staging schemes previously proposed for paddlefishes and other acipenseriforms. Events that occur after the start of neurulation (stage 19) to the start of feeding (stage 46) are emphasized. New information on the structure and folding of the mandibular and hyoid segments permits an understanding of the early development of the pharyngeal region. In addition, we offer new descriptions of the hatching gland, the olfactory organ, the sensory barbel, and the initiation of paddle outgrowth. We also comment on the mode of origin of the hypophysis, and refute the notion that it is derived from the lips of the anterior neuropore as suggested in older literature. This information sets the stage for future comparative and experimental studies of the embryology of basal actinopterygians. © 1992 Wiley‐Liss, Inc.

@article{doi101002jmor1052130106,
    author = "Bemis, William E. and Grande, Lance",
    title = "Early development of the actinopterygian head. I. External development and staging of the paddlefish Polyodon spathula",
    year = "1992",
    journal = "Journal of Morphology",
    abstract = "Abstract A large sample of embryological material of the North American paddlefish Polyodon spathula (Acipenseriformes: Polyodontidae) confirms that early development in Polyodon is very similar to that reported for the sister group of Polyodontidae, the sturgeons (Acipenseridae). Polyodon illustrates many basic aspects of acipenseriform (and actinopterygian) head development that have not been adequately described. In this paper, we provide an overview of external features of cranial development using scanning electron microscopy. The observations are correlated with staging schemes previously proposed for paddlefishes and other acipenseriforms. Events that occur after the start of neurulation (stage 19) to the start of feeding (stage 46) are emphasized. New information on the structure and folding of the mandibular and hyoid segments permits an understanding of the early development of the pharyngeal region. In addition, we offer new descriptions of the hatching gland, the olfactory organ, the sensory barbel, and the initiation of paddle outgrowth. We also comment on the mode of origin of the hypophysis, and refute the notion that it is derived from the lips of the anterior neuropore as suggested in older literature. This information sets the stage for future comparative and experimental studies of the embryology of basal actinopterygians. © 1992 Wiley‐Liss, Inc.",
    url = "https://doi.org/10.1002/jmor.1052130106",
    doi = "10.1002/jmor.1052130106",
    openalex = "W2032509800",
    references = "doi101111j146363951932tb00486x"
}

ABSTRACT The embryology of amphioxus has much in common with vertebrate embryology, reflecting a close phylogenetic relationship between the two groups. Amphioxus embryology is simpler in several key respects, however, including a lack of pronounced craniofacial morphogenesis. To gain an insight into the molecular changes that accompanied the evolution of vertebrate embryology, and into the relationship between the amphioxus and vertebrate body plans, we have undertaken the first molecular level investigation of amphioxus embryonic development. We report the cloning, complete DNA sequence determination, sequence analysis and expression analysis of an amphioxus homeobox gene, AmphiHox3, evolutionarily homologous to the thirdmost 3′ paralogous group of mammalian Hox genes. Sequence comparison to a mammalian homologue, mouse Hox-2.7 (HoxB3), reveals several stretches of amino acid conservation within the deduced protein sequences. Whole mount in situ hybridization reveals localized expression of AmphiHox3 in the posterior mesoderm (but not in the somites), and region-specific expression in the dorsal nerve cord, of amphioxus neurulae, later embryos and larvae. The anterior limit to expression in the nerve cord is at the level of the four/five somite boundary at the neurula stage, and stabilises to just anterior to the first nerve cord pigment spot to form. Comparison to the anterior expression boundary of mouse Hox-2.7 (HoxB3) and related genes suggests that the vertebrate brain is homologous to an extensive region of the amphioxus nerve cord that contains the cerebral vesicle (a region at the extreme rostral tip) and extends posterior to somite four. This proposed homology implies that the vertebrate brain probably did not evolve solely from the cerebral vesicle of an amphioxus-like ancestor, nor did it arise entirely de novo anterior to the cerebral vesicle.

@article{doi101242dev1163653,
    author = "Holland, Peter W. H. and Holland, Linda Z. and Williams, Nicola A. and Holland, Nicholas D.",
    title = "An amphioxus homeobox gene: sequence conservation, spatial expression during development and insights into vertebrate evolution",
    year = "1992",
    journal = "Development",
    abstract = "ABSTRACT The embryology of amphioxus has much in common with vertebrate embryology, reflecting a close phylogenetic relationship between the two groups. Amphioxus embryology is simpler in several key respects, however, including a lack of pronounced craniofacial morphogenesis. To gain an insight into the molecular changes that accompanied the evolution of vertebrate embryology, and into the relationship between the amphioxus and vertebrate body plans, we have undertaken the first molecular level investigation of amphioxus embryonic development. We report the cloning, complete DNA sequence determination, sequence analysis and expression analysis of an amphioxus homeobox gene, AmphiHox3, evolutionarily homologous to the thirdmost 3′ paralogous group of mammalian Hox genes. Sequence comparison to a mammalian homologue, mouse Hox-2.7 (HoxB3), reveals several stretches of amino acid conservation within the deduced protein sequences. Whole mount in situ hybridization reveals localized expression of AmphiHox3 in the posterior mesoderm (but not in the somites), and region-specific expression in the dorsal nerve cord, of amphioxus neurulae, later embryos and larvae. The anterior limit to expression in the nerve cord is at the level of the four/five somite boundary at the neurula stage, and stabilises to just anterior to the first nerve cord pigment spot to form. Comparison to the anterior expression boundary of mouse Hox-2.7 (HoxB3) and related genes suggests that the vertebrate brain is homologous to an extensive region of the amphioxus nerve cord that contains the cerebral vesicle (a region at the extreme rostral tip) and extends posterior to somite four. This proposed homology implies that the vertebrate brain probably did not evolve solely from the cerebral vesicle of an amphioxus-like ancestor, nor did it arise entirely de novo anterior to the cerebral vesicle.",
    url = "https://doi.org/10.1242/dev.116.3.653",
    doi = "10.1242/dev.116.3.653",
    openalex = "W2097360425",
    references = "doi101002j146020751989tb03534x, doi101007bf00291041, doi1010160020711x9390093t, doi1010160092867489909124, doi101016009286749290471n, doi1010160378111988903307, doi101016s0091679x08603076, doi101038313545a0, doi101038353861a0, doi101086413055, doi101242jcss231123445, doi1023071541578, doi105962bhltitle55924"
}

Abstract By observing numerous living eggs from the lesser spotted dogfish Scyliorhinus canicula (L.) caught near Roscoff (France) and reared at recorded temperatures as they developed from first cleavage to hatching, the first reasonably complete developmental table was worked out for this classical material in vertebrate embryology. The successive stages, described and numbered from 1 to 34, correct and replace the incomplete stages A–Q proposed by Balfour (J.Anat. Physiol., 10: 555–576,1876) and other even less complete series later published, and is unique in the inclusion of a timetable at 16°C. The stages can be identified, usually through the cleared eggshell wall, with naked eye or low magnification. This table of normal stages of Scyliorhinus can be adapted with slight modification to other chondrichthyan fishes. © 1993 Wiley‐Liss, Inc.

@article{doi101002jez1402670309,
    author = "Ballard, William W. and Mellinger, J. and Lechenault, Henri",
    title = "A series of normal stages for development of Scyliorhinus canicula, the lesser spotted dogfish (Chondrichthyes: Scyliorhinidae)",
    year = "1993",
    journal = "Journal of Experimental Zoology",
    abstract = "Abstract By observing numerous living eggs from the lesser spotted dogfish Scyliorhinus canicula (L.) caught near Roscoff (France) and reared at recorded temperatures as they developed from first cleavage to hatching, the first reasonably complete developmental table was worked out for this classical material in vertebrate embryology. The successive stages, described and numbered from 1 to 34, correct and replace the incomplete stages A–Q proposed by Balfour (J.Anat. Physiol., 10: 555–576,1876) and other even less complete series later published, and is unique in the inclusion of a timetable at 16°C. The stages can be identified, usually through the cleared eggshell wall, with naked eye or low magnification. This table of normal stages of Scyliorhinus can be adapted with slight modification to other chondrichthyan fishes. © 1993 Wiley‐Liss, Inc.",
    url = "https://doi.org/10.1002/jez.1402670309",
    doi = "10.1002/jez.1402670309",
    openalex = "W2053431317",
    references = "balfour1878a, doi101002jmor1050880104, doi1010079781461305033, doi101016s0168952500891295, doi101017s002531540005298x, doi101098rstb19390008, doi1023071439568, doi105962bhltitle3929, doi105962bhltitle7847, openalexw1534646565, openalexw2231568404"
}

Limb muscles in vertebrates originate from dermomyotomal cells, which during early development migrate from the ventrolateral region of somites into the limb buds. These progenitor cells do not express any muscle-specific marker genes or myogenic transcription factors until they reach their destination in the limbs. Here, we demonstrate by in situ hybridization that myogenic cells in somites and a population of presumably migratory muscle precursor cells in somatopleural tissue as well as myoblasts in the developing limbs express Pax-3. Significantly, in homozygous splotch mutant mice, which synthesize altered Pax-3 mRNA but make no normal protein, no cells positive for Pax-3 transcripts can be detected in the region of migrating limb muscle precursors or in the limb itself. In contrast, myotomal precursor cells and axial skeletal muscles contain Pax-3 transcripts also in the mutant. Interestingly, these animals fail to develop limb musculature as demonstrated by the lack of hybridization with various probes for myogenic transcription factors (Myf-5, myogenin, MyoD) but make apparently normal axial muscles. These observations suggest that Pax-3 is necessary for the formation of limb muscles, affecting either the generation of myogenic precursors in the somitic dermomyotome or the migration of these cells into the limb field.

@article{doi101242dev1203603,
    author = "Bober, Eva and Franz, Thomas and Arnold, Hans-Henning and Gruß, Peter and Tremblay, Patrick",
    title = "Pax-3 is required for the development of limb muscles: a possible role for the migration of dermomyotomal muscle progenitor cells",
    year = "1994",
    journal = "Development",
    abstract = "Limb muscles in vertebrates originate from dermomyotomal cells, which during early development migrate from the ventrolateral region of somites into the limb buds. These progenitor cells do not express any muscle-specific marker genes or myogenic transcription factors until they reach their destination in the limbs. Here, we demonstrate by in situ hybridization that myogenic cells in somites and a population of presumably migratory muscle precursor cells in somatopleural tissue as well as myoblasts in the developing limbs express Pax-3. Significantly, in homozygous splotch mutant mice, which synthesize altered Pax-3 mRNA but make no normal protein, no cells positive for Pax-3 transcripts can be detected in the region of migrating limb muscle precursors or in the limb itself. In contrast, myotomal precursor cells and axial skeletal muscles contain Pax-3 transcripts also in the mutant. Interestingly, these animals fail to develop limb musculature as demonstrated by the lack of hybridization with various probes for myogenic transcription factors (Myf-5, myogenin, MyoD) but make apparently normal axial muscles. These observations suggest that Pax-3 is necessary for the formation of limb muscles, affecting either the generation of myogenic precursors in the somitic dermomyotome or the migration of these cells into the limb field.",
    url = "https://doi.org/10.1242/dev.120.3.603",
    doi = "10.1242/dev.120.3.603",
    openalex = "W2161699162",
    references = "doi101002aja1001680302"
}

In a large-scale screen, we isolated mutants displaying a specific visible phenotype in embryos or early larvae of the zebrafish, Danio rerio. Males were mutagenized with ethylnitrosourea (ENU) and F2 families of single pair matings between sibling F1 fish, heterozygous for a mutagenized genome, were raised. Egg lays were obtained from several crosses between F2 siblings, resulting in scoring of 3857 mutagenized genomes. F3 progeny were scored at the second, third and sixth day of development, using a stereomicroscope. In a subsequent screen, fixed embryos were analyzed for correct retinotectal projection. A total of 4264 mutants were identified. Two thirds of the mutants displaying rather general abnormalities were eventually discarded. We kept and characterized 1163 mutants. In complementation crosses performed between mutants with similar phenotypes, 894 mutants have been assigned to 372 genes. The average allele frequency is 2.4. We identified genes involved in early development, notochord, brain, spinal cord, somites, muscles, heart, circulation, blood, skin, fin, eye, otic vesicle, jaw and branchial arches, pigment pattern, pigment formation, gut, liver, motility and touch response. Our collection contains alleles of almost all previously described zebrafish mutants. From the allele frequencies and other considerations we estimate that the 372 genes defined by the mutants probably represent more than half of all genes that could have been discovered using the criteria of our screen. Here we give an overview of the spectrum of mutant phenotypes obtained, and discuss the limits and the potentials of a genetic saturation screen in the zebrafish.

@article{doi101242dev12311,
    author = "Haffter, Pascal and Granato, Michael and Brand, Michael and Mullins, Mary C. and Hammerschmidt, Matthias and Kane, Donald A. and Odenthal, Jörg and van Eeden, Fredericus J. M. and Jiang, Yun‐Jin and Heisenberg, Carl‐Philipp and Kelsh, Robert N. and Furutani‐Seiki, Makoto and Vogelsang, Elisabeth and Beuchle, Dirk and Schach, Ursula and Fabian, Cosima and Nüsslein‐Volhard, Christiane",
    title = "The identification of genes with unique and essential functions in the development of the zebrafish, Danio rerio",
    year = "1996",
    journal = "Development",
    abstract = "In a large-scale screen, we isolated mutants displaying a specific visible phenotype in embryos or early larvae of the zebrafish, Danio rerio. Males were mutagenized with ethylnitrosourea (ENU) and F2 families of single pair matings between sibling F1 fish, heterozygous for a mutagenized genome, were raised. Egg lays were obtained from several crosses between F2 siblings, resulting in scoring of 3857 mutagenized genomes. F3 progeny were scored at the second, third and sixth day of development, using a stereomicroscope. In a subsequent screen, fixed embryos were analyzed for correct retinotectal projection. A total of 4264 mutants were identified. Two thirds of the mutants displaying rather general abnormalities were eventually discarded. We kept and characterized 1163 mutants. In complementation crosses performed between mutants with similar phenotypes, 894 mutants have been assigned to 372 genes. The average allele frequency is 2.4. We identified genes involved in early development, notochord, brain, spinal cord, somites, muscles, heart, circulation, blood, skin, fin, eye, otic vesicle, jaw and branchial arches, pigment pattern, pigment formation, gut, liver, motility and touch response. Our collection contains alleles of almost all previously described zebrafish mutants. From the allele frequencies and other considerations we estimate that the 372 genes defined by the mutants probably represent more than half of all genes that could have been discovered using the criteria of our screen. Here we give an overview of the spectrum of mutant phenotypes obtained, and discuss the limits and the potentials of a genetic saturation screen in the zebrafish.",
    url = "https://doi.org/10.1242/dev.123.1.1",
    doi = "10.1242/dev.123.1.1",
    openalex = "W2123938765",
    references = "doi101002aja1002030302"
}

Fishes show one of the widest ranges of sperm competition intensity of any animal group. Here we present a comparative study whose aim is to investigate the effect of relative intensity of sperm competition on investment in spermatogenesis and the number and size of sperm produced. We find that both the gonadosomatic index (GSI = [gonad weight/body weight] x 100) and sperm numbers increase with intensity of sperm competition across species but that sperm length decreases. These new findings are consistent with a raffle-based mode of sperm competition in fishes. Most of these results (positive correlation of the GSI and sperm number with sperm competition intensity) concur with the predictions of current sperm competition theory. However, we also find that sperm longevity decreases with sperm length across species. Current models for continuous fertilization suggest that if length increases a sperm's speed but decreases its longevity, sperm length should increase with sperm competition intensity, whereas models for instant fertilization suggest that sperm length should remain constant. The negative relationship found between sperm competition and sperm length therefore does not fit predictions of either model.

@article{doi101086286031,
    author = "Stockley, Paula and Gage, M. J. G. and Parker, George A. and Møller, Anders Pape",
    title = "Sperm Competition in Fishes: The Evolution of Testis Size and Ejaculate Characteristics",
    year = "1997",
    journal = "The American Naturalist",
    abstract = "Fishes show one of the widest ranges of sperm competition intensity of any animal group. Here we present a comparative study whose aim is to investigate the effect of relative intensity of sperm competition on investment in spermatogenesis and the number and size of sperm produced. We find that both the gonadosomatic index (GSI = [gonad weight/body weight] x 100) and sperm numbers increase with intensity of sperm competition across species but that sperm length decreases. These new findings are consistent with a raffle-based mode of sperm competition in fishes. Most of these results (positive correlation of the GSI and sperm number with sperm competition intensity) concur with the predictions of current sperm competition theory. However, we also find that sperm longevity decreases with sperm length across species. Current models for continuous fertilization suggest that if length increases a sperm's speed but decreases its longevity, sperm length should increase with sperm competition intensity, whereas models for instant fertilization suggest that sperm length should remain constant. The negative relationship found between sperm competition and sperm length therefore does not fit predictions of either model.",
    url = "https://doi.org/10.1086/286031",
    doi = "10.1086/286031",
    openalex = "W2126945764",
    references = "openalexw612600151"
}

We report the results of a comparative survey of the structure and function of oviducal glands (OG) of selected elasmobranch fish with differing modes of reproduction using light and scanning electron microscopy, e.g., Scyliorhinus canicula, S. stellaris, Raja erinacea, R. eglanteria, R. clavata, Squalus acanthias, Mustelus canis, and Urolophus jamaicensis. Oviducal glands consistently display four fundamental zones regardless of the type of reproduction of the particular species. The zones correspond to lamellae that extend full width across the gland lumen. Formerly, zones of OG were designated as albumen secreting and shell secreting. This oversimplified terminology does not accurately apply to all species. We have adopted the terminology recently introduced (Hamlett et al. [1998] Cybium, in press) that refers to the four basic zones on a morphological basis rather than on a purported function that may not be applicable across species lines. This allows comparisons to be accurately made between species. Oviducal glands have a proximal club zone, papillary zone, baffle zone, and terminal zone. Variations in the makeup of each zone may show species variability, but the fundamental organization is maintained. The club and papillary zones replace the former designation of the albumen zone. The club zone is so named because of its shape when viewed in transverse section with the light microscope. Similarly, the papillary zone is characterized by a papillary or conical profile when viewed in section. The club and papillary zones are responsible for producing the various jelly coats that surround the egg. The baffle zone produces the various types of egg investments seen in elasmobranchs. In oviparous species, such as the sharks S. Canicula and S. Stellaris and the skates R. Erinacea, R. Eglanteria,and R. Clavata, tubular glands produce secretory components that pass to secretory ducts. Secretory ducts are confluent with a spinneret that has paired baffle plates that manipulate the secretory material as it emerges from the secretory duct. Secretory material from adjacent secretory ducts blends in transverse grooves that extend across the full width of the gland, thus one transverse groove is responsible for one secreted layer. The yellow spotted stingray, U. Jamaicensis, is unusual in that it does not produce an egg investiture other than jelly coats and therefore lacks baffle plates. Despite variations among species, the capsule-producing OG we studied seems to use the same basic assembly process to produce tough, flexible, and selectively permeable egg capsules, candles, or egg envelopes. This involves the extrusion of a capsule material through dies, each of which opens between two baffle plates and extrudes a flattened ribbon containing precisely and complexly orientated molecules. The dies discharge into transverse grooves in the main lumen of the gland, each groove thus secreting a single lamella of the egg covering. J. Exp. Zool. 282:399–420, 1998. © 1998 Wiley-Liss, Inc.

@article{doi101002sici1097010x1998111228245399aidjez230co26,
    author = "Hamlett, William C. and Knight, D.P. and Koob, Thomas J. and Jezior, M. and Luong, Thanh-Truc and Rozycki, T. and Brunette, N. and Hysell, Matthew",
    title = "Survey of oviducal gland structure and function in elasmobranchs",
    year = "1998",
    journal = "Journal of Experimental Zoology",
    abstract = "We report the results of a comparative survey of the structure and function of oviducal glands (OG) of selected elasmobranch fish with differing modes of reproduction using light and scanning electron microscopy, e.g., Scyliorhinus canicula, S. stellaris, Raja erinacea, R. eglanteria, R. clavata, Squalus acanthias, Mustelus canis, and Urolophus jamaicensis. Oviducal glands consistently display four fundamental zones regardless of the type of reproduction of the particular species. The zones correspond to lamellae that extend full width across the gland lumen. Formerly, zones of OG were designated as albumen secreting and shell secreting. This oversimplified terminology does not accurately apply to all species. We have adopted the terminology recently introduced (Hamlett et al. [1998] Cybium, in press) that refers to the four basic zones on a morphological basis rather than on a purported function that may not be applicable across species lines. This allows comparisons to be accurately made between species. Oviducal glands have a proximal club zone, papillary zone, baffle zone, and terminal zone. Variations in the makeup of each zone may show species variability, but the fundamental organization is maintained. The club and papillary zones replace the former designation of the albumen zone. The club zone is so named because of its shape when viewed in transverse section with the light microscope. Similarly, the papillary zone is characterized by a papillary or conical profile when viewed in section. The club and papillary zones are responsible for producing the various jelly coats that surround the egg. The baffle zone produces the various types of egg investments seen in elasmobranchs. In oviparous species, such as the sharks S. Canicula and S. Stellaris and the skates R. Erinacea, R. Eglanteria,and R. Clavata, tubular glands produce secretory components that pass to secretory ducts. Secretory ducts are confluent with a spinneret that has paired baffle plates that manipulate the secretory material as it emerges from the secretory duct. Secretory material from adjacent secretory ducts blends in transverse grooves that extend across the full width of the gland, thus one transverse groove is responsible for one secreted layer. The yellow spotted stingray, U. Jamaicensis, is unusual in that it does not produce an egg investiture other than jelly coats and therefore lacks baffle plates. Despite variations among species, the capsule-producing OG we studied seems to use the same basic assembly process to produce tough, flexible, and selectively permeable egg capsules, candles, or egg envelopes. This involves the extrusion of a capsule material through dies, each of which opens between two baffle plates and extrudes a flattened ribbon containing precisely and complexly orientated molecules. The dies discharge into transverse grooves in the main lumen of the gland, each groove thus secreting a single lamella of the egg covering. J. Exp. Zool. 282:399–420, 1998. © 1998 Wiley-Liss, Inc.",
    url = "https://doi.org/10.1002/(sici)1097-010x(199811/12)282:4/5<399::aid-jez2>3.0.co;2-6",
    doi = "10.1002/(sici)1097-010x(199811/12)282:4/5<399::aid-jez2>3.0.co;2-6",
    openalex = "W2014891025",
    references = "doi101017s002531540000967x"
}

Abstract This chapter describes the species richness and phylogenetic relationships among the Neotropical freshwater fish, emphasizing the main diagnostic characteristics of each group. Both themes are effervescent, involving studies and discussions that require constant updates. They also face a high rate of descriptions of new species and new relationship hypotheses. In this chapter, we provide a picture of the knowledge available through early 2018, and we suggest that readers use it to search for updated information.

@book{openalexw3001739384,
    author = "Malabarba, Luiz Roberto and Malabarba, Maria Claudia",
    title = "Phylogeny and classification of neotropical fishes",
    year = "1998",
    abstract = "Abstract This chapter describes the species richness and phylogenetic relationships among the Neotropical freshwater fish, emphasizing the main diagnostic characteristics of each group. Both themes are effervescent, involving studies and discussions that require constant updates. They also face a high rate of descriptions of new species and new relationship hypotheses. In this chapter, we provide a picture of the knowledge available through early 2018, and we suggest that readers use it to search for updated information.",
    openalex = "W3001739384",
    references = "doi101002aja1001590307, doi101007978940171356617, doi101007pl00006514, doi101093icb222241, doi101111j109636421981tb01575x, doi101111j109636421996tb02189x, doi101159000006600, doi1011632666064402801038, doi1023071441405, doi1023071446263"
}

We report the generation and analysis of mice homozygous for a targeted deletion of the Dlx5 homeobox gene. Dlx5 mutant mice have multiple defects in craniofacial structures, including their ears, noses, mandibles and calvaria, and die shortly after birth. A subset (28%) exhibit exencephaly. Ectodermal expression of Dlx5 is required for the development of olfactory and otic placode-derived epithelia and surrounding capsules. The nasal capsules are hypoplastic (e.g. lacking turbinates) and, in most cases, the right side is more severely affected than the left. Dorsal otic vesicle derivatives (e. g. semicircular canals and endolymphatic duct) and the surrounding capsule, are more severely affected than ventral (cochlear) structures. Dlx5 is also required in mandibular arch ectomesenchyme, as the proximal mandibular arch skeleton is dysmorphic. Dlx5 may control craniofacial development in part through the regulation of the goosecoid homeobox gene. goosecoid expression is greatly reduced in Dlx5 mutants, and both goosecoid and Dlx5 mutants share a number of similar craniofacial malformations. Dlx5 may perform a general role in skeletal differentiation, as exemplified by hypomineralization within the calvaria. The distinct focal defects within the branchial arches of the Dlx1, Dlx2 and Dlx5 mutants, along with the nested expression of their RNAs, support a model in which these genes have both redundant and unique functions in the regulation of regional patterning of the craniofacial ectomesenchyme.

@article{doi101242dev126173831,
    author = "Depew, Michael J. and Liu, Jen Kuei and Long, Jason E. and Presley, R. and Meneses, Juanito J. and Pedersen, Roger A. and Rubenstein, John L.R.",
    title = "Dlx5 regulates regional development of the branchial arches and sensory capsules",
    year = "1999",
    journal = "Development",
    abstract = "We report the generation and analysis of mice homozygous for a targeted deletion of the Dlx5 homeobox gene. Dlx5 mutant mice have multiple defects in craniofacial structures, including their ears, noses, mandibles and calvaria, and die shortly after birth. A subset (28\%) exhibit exencephaly. Ectodermal expression of Dlx5 is required for the development of olfactory and otic placode-derived epithelia and surrounding capsules. The nasal capsules are hypoplastic (e.g. lacking turbinates) and, in most cases, the right side is more severely affected than the left. Dorsal otic vesicle derivatives (e. g. semicircular canals and endolymphatic duct) and the surrounding capsule, are more severely affected than ventral (cochlear) structures. Dlx5 is also required in mandibular arch ectomesenchyme, as the proximal mandibular arch skeleton is dysmorphic. Dlx5 may control craniofacial development in part through the regulation of the goosecoid homeobox gene. goosecoid expression is greatly reduced in Dlx5 mutants, and both goosecoid and Dlx5 mutants share a number of similar craniofacial malformations. Dlx5 may perform a general role in skeletal differentiation, as exemplified by hypomineralization within the calvaria. The distinct focal defects within the branchial arches of the Dlx1, Dlx2 and Dlx5 mutants, along with the nested expression of their RNAs, support a model in which these genes have both redundant and unique functions in the regulation of regional patterning of the craniofacial ectomesenchyme.",
    url = "https://doi.org/10.1242/dev.126.17.3831",
    doi = "10.1242/dev.126.17.3831",
    openalex = "W2148339830",
    references = "doi1010970000505319311100000026"
}

The impact of fishing on chondrichthyan stocks around the world is currently the focus of considerable international concern. Most chondrichthyan populations are of low productivity relative to teleost fishes, a consequence of their different life-history strategies. This is reflected in the poor record of sustainability of target shark fisheries. Most sharks and some batoids are predators at, or near, the top of marine food webs. The effects of fishing are examined at the single-species level and through trophic interactions. We summarize the status of chondrichthyan fisheries from around the world. Some 50% of the estimated global catch of chondrichthyans is taken as by-catch, does not appear in official fishery statistics, and is almost totally unmanaged. When taken as by-catch, they are often subjected to high fishing mortality directed at teleost target species. Consequently, some skates, sawfish, and deep-water dogfish have been virtually extirpated from large regions. Some chondrichthyans are more resilient to fishing and we examine predictions on the vulnerability of different species based on their life-history and population parameters. At the species level, fishing may alter size structure and population parameters in response to changes in species abundance. We review the evidence for such density-dependent change. Fishing can affect trophic interactions and we examine cases of apparent species replacement and shifts in community composition. Sharks and rays learn to associate trawlers with food and feeding on discards may increase their populations. Using ECOSIM, we make some predictions about the long-term response of ecosystems to fishing on sharks. Three different environments are analysed: a tropical shelf ecosystem in Venezuela, a Hawaiian coral reef ecosystem, and a North Pacific oceanic ecosystem.

@article{doi101006jmsc20000724,
    author = "Stevens, John D.",
    title = "The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems",
    year = "2000",
    journal = "ICES Journal of Marine Science",
    abstract = "The impact of fishing on chondrichthyan stocks around the world is currently the focus of considerable international concern. Most chondrichthyan populations are of low productivity relative to teleost fishes, a consequence of their different life-history strategies. This is reflected in the poor record of sustainability of target shark fisheries. Most sharks and some batoids are predators at, or near, the top of marine food webs. The effects of fishing are examined at the single-species level and through trophic interactions. We summarize the status of chondrichthyan fisheries from around the world. Some 50\% of the estimated global catch of chondrichthyans is taken as by-catch, does not appear in official fishery statistics, and is almost totally unmanaged. When taken as by-catch, they are often subjected to high fishing mortality directed at teleost target species. Consequently, some skates, sawfish, and deep-water dogfish have been virtually extirpated from large regions. Some chondrichthyans are more resilient to fishing and we examine predictions on the vulnerability of different species based on their life-history and population parameters. At the species level, fishing may alter size structure and population parameters in response to changes in species abundance. We review the evidence for such density-dependent change. Fishing can affect trophic interactions and we examine cases of apparent species replacement and shifts in community composition. Sharks and rays learn to associate trawlers with food and feeding on discards may increase their populations. Using ECOSIM, we make some predictions about the long-term response of ecosystems to fishing on sharks. Three different environments are analysed: a tropical shelf ecosystem in Venezuela, a Hawaiian coral reef ecosystem, and a North Pacific oceanic ecosystem.",
    url = "https://doi.org/10.1006/jmsc.2000.0724",
    doi = "10.1006/jmsc.2000.0724",
    openalex = "W2121792431",
    references = "doi101006jmsc19990489, doi101098rspb19970181, doi101126science2795352860, doi1023071447035, doi1023071447424"
}

Abstract Density‐dependent processes such as growth, survival, reproduction and movement are compensatory if their rates change in response to variation in population density (or numbers) such that they result in a slowed population growth rate at high densities and promote a numerical increase of the population at low densities. Compensatory density dependence is important to fisheries management because it operates to offset the losses of individuals. While the concept of compensation is straightforward, it remains one of the most controversial issues in population dynamics. The difficulties arise when going from general concepts to specific populations. Compensation is usually quantified using some combination of spawner–recruit analysis, long‐term field monitoring or manipulative studies, and computer modelling. Problems arise because there are limitations to each of these approaches, and these limitations generally originate from the high uncertainty associated with field measurements. We offer a hierarchical approach to predicting and understanding compensation that ranges from the very general, using basic life‐history theory, to the highly site‐specific, using detailed population models. We analyse a spawner–recruit database to test the predictions about compensation and compensatory reserve that derive from a three‐endpoint life‐history framework designed for fish. We then summarise field examples of density dependence in specific processes. Selected long‐term field monitoring studies, manipulative studies and computer modelling examples are then highlighted that illustrate how density‐dependent processes led to compensatory responses at the population level. Some theoretical and empirical advances that offer hope for progress in the future on the compensation issue are discussed. We advocate an approach to compensation that involves process‐level understanding of the underlying mechanisms, life‐history theory, careful analysis of field data, and matrix and individual‐based modelling. There will always be debate if the quantification of compensation does not include some degree of understanding of the underlying mechanisms.

@article{doi101046j14672960200100056x,
    author = "Rose, Kenneth A. and Cowan, James H. and Winemiller, Kirk O. and Myers, Ransom A. and Hilborn, Ray",
    title = "Compensatory density dependence in fish populations: importance, controversy, understanding and prognosis",
    year = "2001",
    journal = "Fish and Fisheries",
    abstract = "Abstract Density‐dependent processes such as growth, survival, reproduction and movement are compensatory if their rates change in response to variation in population density (or numbers) such that they result in a slowed population growth rate at high densities and promote a numerical increase of the population at low densities. Compensatory density dependence is important to fisheries management because it operates to offset the losses of individuals. While the concept of compensation is straightforward, it remains one of the most controversial issues in population dynamics. The difficulties arise when going from general concepts to specific populations. Compensation is usually quantified using some combination of spawner–recruit analysis, long‐term field monitoring or manipulative studies, and computer modelling. Problems arise because there are limitations to each of these approaches, and these limitations generally originate from the high uncertainty associated with field measurements. We offer a hierarchical approach to predicting and understanding compensation that ranges from the very general, using basic life‐history theory, to the highly site‐specific, using detailed population models. We analyse a spawner–recruit database to test the predictions about compensation and compensatory reserve that derive from a three‐endpoint life‐history framework designed for fish. We then summarise field examples of density dependence in specific processes. Selected long‐term field monitoring studies, manipulative studies and computer modelling examples are then highlighted that illustrate how density‐dependent processes led to compensatory responses at the population level. Some theoretical and empirical advances that offer hope for progress in the future on the compensation issue are discussed. We advocate an approach to compensation that involves process‐level understanding of the underlying mechanisms, life‐history theory, careful analysis of field data, and matrix and individual‐based modelling. There will always be debate if the quantification of compensation does not include some degree of understanding of the underlying mechanisms.",
    url = "https://doi.org/10.1046/j.1467-2960.2001.00056.x",
    doi = "10.1046/j.1467-2960.2001.00056.x",
    openalex = "W2132380992",
    references = "doi101007bf00042661, doi101016s006528810860187x, doi101111j193974452001tb00075x, doi1023072937041, doi103354meps188263"
}

The construction of organisms from units that develop under semi-autonomous genetic control (modules) has been proposed to be an important component of their ability to undergo adaptive phenotypic evolution. The organization of the vertebrate dentition as a system of repeated parts provides an opportunity to study the extent to which phenotypic modules, identified by their evolutionary independence from other such units, are related to modularity in the genetic control of development. The evolutionary history of vertebrates provides numerous examples of both correlated and independent evolution of groups of teeth. The dentition itself appears to be a module of the dermal exoskeleton, from which it has long been under independent genetic control. Region-specific tooth loss has been a common trend in vertebrate evolution. Novel deployment of teeth and reacquisition of lost teeth have also occurred, although less frequently. Tooth shape differences within the dentition may be discontinuous (referred to as heterodonty) or graded. The occurrence of homeotic changes in tooth shape provides evidence for the decoupling of tooth shape and location in the course of evolution. Potential mechanisms for region-specific evolutionary tooth loss are suggested by a number of mouse gene knockouts and human genetic dental anomalies, as well as a comparison between fully-developed and rudimentary teeth in the dentition of rodents. These mechanisms include loss of a tooth-type-specific initiation signal, alterations of the relative strength of inductive and inhibitory signals acting at the time of tooth initiation and the overall reduction in levels of proteins required for the development of all teeth. Ectopic expression of tooth initiation signals provides a potential mechanism for the novel deployment or reacquisition of teeth; a single instance is known of a gene whose ectopic expression in transgenic mice can lead to ectopic teeth. Differences in shape between incisor and molar teeth in the mouse have been proposed to be controlled by the region-specific expression of signalling molecules in the oral epithelium. These molecules induce the expression of transcription factors in the underlying jaw mesenchyme that may act as selectors of tooth type. It is speculated that shifts in the expression domains of the epithelial signalling molecules might be responsible for homeotic changes in tooth shape. The observation that these molecules are regionally restricted in the chicken, whose ancestors were not heterodont, suggests that mammalian heterodonty may have evolved through the use of patterning mechanisms already acting on skeletal elements of the jaws. In general, genetic and morphological approaches identify similar types of modules in the dentition, but the data are not yet sufficient to identify exact correspondences. It is speculated that modularity may be achieved by gene expression differences between teeth or by differences in the time of their development, causing mutations to have cumulative effects on later-developing teeth. The mammalian dentition, for which virtually all of the available developmental genetic data have been collected, represents a small subset of the dental diversity present in vertebrates as a whole. In particular, teleost fishes may have a much more extensive dentition. Extension of research on the genetic control of tooth development to this and other vertebrate groups has great potential to further the understanding of modularity in the dentition.

@article{doi101098rstb20010917,
    author = "Stock, David W.",
    title = "The genetic basis of modularity in the development and evolution of the vertebrate dentition",
    year = "2001",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "The construction of organisms from units that develop under semi-autonomous genetic control (modules) has been proposed to be an important component of their ability to undergo adaptive phenotypic evolution. The organization of the vertebrate dentition as a system of repeated parts provides an opportunity to study the extent to which phenotypic modules, identified by their evolutionary independence from other such units, are related to modularity in the genetic control of development. The evolutionary history of vertebrates provides numerous examples of both correlated and independent evolution of groups of teeth. The dentition itself appears to be a module of the dermal exoskeleton, from which it has long been under independent genetic control. Region-specific tooth loss has been a common trend in vertebrate evolution. Novel deployment of teeth and reacquisition of lost teeth have also occurred, although less frequently. Tooth shape differences within the dentition may be discontinuous (referred to as heterodonty) or graded. The occurrence of homeotic changes in tooth shape provides evidence for the decoupling of tooth shape and location in the course of evolution. Potential mechanisms for region-specific evolutionary tooth loss are suggested by a number of mouse gene knockouts and human genetic dental anomalies, as well as a comparison between fully-developed and rudimentary teeth in the dentition of rodents. These mechanisms include loss of a tooth-type-specific initiation signal, alterations of the relative strength of inductive and inhibitory signals acting at the time of tooth initiation and the overall reduction in levels of proteins required for the development of all teeth. Ectopic expression of tooth initiation signals provides a potential mechanism for the novel deployment or reacquisition of teeth; a single instance is known of a gene whose ectopic expression in transgenic mice can lead to ectopic teeth. Differences in shape between incisor and molar teeth in the mouse have been proposed to be controlled by the region-specific expression of signalling molecules in the oral epithelium. These molecules induce the expression of transcription factors in the underlying jaw mesenchyme that may act as selectors of tooth type. It is speculated that shifts in the expression domains of the epithelial signalling molecules might be responsible for homeotic changes in tooth shape. The observation that these molecules are regionally restricted in the chicken, whose ancestors were not heterodont, suggests that mammalian heterodonty may have evolved through the use of patterning mechanisms already acting on skeletal elements of the jaws. In general, genetic and morphological approaches identify similar types of modules in the dentition, but the data are not yet sufficient to identify exact correspondences. It is speculated that modularity may be achieved by gene expression differences between teeth or by differences in the time of their development, causing mutations to have cumulative effects on later-developing teeth. The mammalian dentition, for which virtually all of the available developmental genetic data have been collected, represents a small subset of the dental diversity present in vertebrates as a whole. In particular, teleost fishes may have a much more extensive dentition. Extension of research on the genetic control of tooth development to this and other vertebrate groups has great potential to further the understanding of modularity in the dentition.",
    url = "https://doi.org/10.1098/rstb.2001.0917",
    doi = "10.1098/rstb.2001.0917",
    openalex = "W2014935796",
    references = "doi101002jmor1051660303"
}

In fresh water fishes, ammonia is excreted across the branchial epithelium via passive NH(3) diffusion. This NH(3) is subsequently trapped as NH(4)(+) in an acidic unstirred boundary layer lying next to the gill, which maintains the blood-to-gill water NH(3) partial pressure gradient. Whole animal, in situ, ultrastructural and molecular approaches suggest that boundary layer acidification results from the hydration of CO(2) in the expired gill water, and to a lesser extent H(+) excretion mediated by apical H(+)-ATPases. Boundary layer acidification is insignificant in highly buffered sea water, where ammonia excretion proceeds via NH(3) diffusion, as well as passive NH(4)(+) diffusion due to the greater ionic permeability of marine fish gills. Although Na(+)/H(+) exchangers (NHE) have been isolated in marine fish gills, possible Na(+)/NH(4)(+) exchange via these proteins awaits evaluation using modern electrophysiological and molecular techniques. Although urea excretion (J(Urea)) was thought to be via passive diffusion, it is now clear that branchial urea handling requires specialized urea transporters. Four urea transporters have been cloned in fishes, including the shark kidney urea transporter (shUT), which is a facilitated urea transporter similar to the mammalian renal UT-A2 transporter. Another urea transporter, characterized but not yet cloned, is the basolateral, Na(+) dependent urea antiporter of the dogfish gill, which is essential for urea retention in ureosmotic elasmobranchs. In ureotelic teleosts such as the Lake Magadi tilapia and the gulf toadfish, the cloned mtUT and tUT are facilitated urea transporters involved in J(Urea). A basolateral urea transporter recently cloned from the gill of the Japanese eel (eUT) may actually be important for urea retention during salt water acclimation. A multi-faceted approach, incorporating whole animal, histological, biochemical, pharmacological, and molecular techniques is required to learn more about the location, mechanism of action, and functional significance of urea transporters in fishes.

@article{doi101002jez10123,
    author = "Wilkie, Michael P.",
    title = "Ammonia excretion and urea handling by fish gills: present understanding and future research challenges",
    year = "2002",
    journal = "Journal of Experimental Zoology",
    abstract = "In fresh water fishes, ammonia is excreted across the branchial epithelium via passive NH(3) diffusion. This NH(3) is subsequently trapped as NH(4)(+) in an acidic unstirred boundary layer lying next to the gill, which maintains the blood-to-gill water NH(3) partial pressure gradient. Whole animal, in situ, ultrastructural and molecular approaches suggest that boundary layer acidification results from the hydration of CO(2) in the expired gill water, and to a lesser extent H(+) excretion mediated by apical H(+)-ATPases. Boundary layer acidification is insignificant in highly buffered sea water, where ammonia excretion proceeds via NH(3) diffusion, as well as passive NH(4)(+) diffusion due to the greater ionic permeability of marine fish gills. Although Na(+)/H(+) exchangers (NHE) have been isolated in marine fish gills, possible Na(+)/NH(4)(+) exchange via these proteins awaits evaluation using modern electrophysiological and molecular techniques. Although urea excretion (J(Urea)) was thought to be via passive diffusion, it is now clear that branchial urea handling requires specialized urea transporters. Four urea transporters have been cloned in fishes, including the shark kidney urea transporter (shUT), which is a facilitated urea transporter similar to the mammalian renal UT-A2 transporter. Another urea transporter, characterized but not yet cloned, is the basolateral, Na(+) dependent urea antiporter of the dogfish gill, which is essential for urea retention in ureosmotic elasmobranchs. In ureotelic teleosts such as the Lake Magadi tilapia and the gulf toadfish, the cloned mtUT and tUT are facilitated urea transporters involved in J(Urea). A basolateral urea transporter recently cloned from the gill of the Japanese eel (eUT) may actually be important for urea retention during salt water acclimation. A multi-faceted approach, incorporating whole animal, histological, biochemical, pharmacological, and molecular techniques is required to learn more about the location, mechanism of action, and functional significance of urea transporters in fishes.",
    url = "https://doi.org/10.1002/jez.10123",
    doi = "10.1002/jez.10123",
    openalex = "W2079933355",
    references = "doi101111j1469185x1936tb00497x, doi101242jeb1982273, openalexw2170405949"
}

This review summarizes information on filial cannibalism (the act of eating one's own offspring) in teleost fish. Cannibalistic parents can either consume their whole brood (total filial cannibalism), or eat only some of the eggs in the nest (partial filial cannibalism). Offspring consumption has been argued to be adaptive under the assumption that offspring survival is traded against feeding, and that offspring can act as an alternative food source for the parents. The evidence supporting the basic predictions formulated under these assumptions is summarized for both total and partial filial cannibalism. These two forms of cannibalism differ significantly since the former represents an investment only in future reproductive success, whereas the latter can affect both present and future reproductive success. Despite a few inconsistencies in the data from laboratory and field studies, the energy-based explanation appears valid for both forms of cannibalism. Alternative non-energy-based explanations are considered, but they are unable to account for the wide distribution of this behaviour in teleosts. The intersexual conflict arising from attempts of the non-cannibal sex to minimize the cost of filial cannibalism is also discussed, together with the potential effect of this behaviour on the operational sex ratio at a population level.

@article{doi101017s1464793101005905,
    author = "Manica, Andrea",
    title = "Filial cannibalism in teleost fish",
    year = "2002",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "This review summarizes information on filial cannibalism (the act of eating one's own offspring) in teleost fish. Cannibalistic parents can either consume their whole brood (total filial cannibalism), or eat only some of the eggs in the nest (partial filial cannibalism). Offspring consumption has been argued to be adaptive under the assumption that offspring survival is traded against feeding, and that offspring can act as an alternative food source for the parents. The evidence supporting the basic predictions formulated under these assumptions is summarized for both total and partial filial cannibalism. These two forms of cannibalism differ significantly since the former represents an investment only in future reproductive success, whereas the latter can affect both present and future reproductive success. Despite a few inconsistencies in the data from laboratory and field studies, the energy-based explanation appears valid for both forms of cannibalism. Alternative non-energy-based explanations are considered, but they are unable to account for the wide distribution of this behaviour in teleosts. The intersexual conflict arising from attempts of the non-cannibal sex to minimize the cost of filial cannibalism is also discussed, together with the potential effect of this behaviour on the operational sex ratio at a population level.",
    url = "https://doi.org/10.1017/s1464793101005905",
    doi = "10.1017/s1464793101005905",
    openalex = "W2079225060",
    references = "doi101007bf00042661"
}

Abstract Cannibalism is a frequent phenomenon in fish, especially in culture environments where fish are unable to escape predation via habitat segregation or migration. Not all cultured fish species start to exhibit cannibalism at the same age or size, nor is cannibalism equally intense in different species or life stages. Predator to prey size ratios vary substantially between species and life stages, chiefly because cannibalism is governed by gape size limitations and allometric growth of mouthparts. The development of sense organs, hard body parts, swimming and escape capacities in both the predator and the prey also influence prey size selectivity. The dynamics of cannibalism are influenced by these, as well as by environmental, factors that have effects on feed intake, growth depensation and facilitate or complicate the displaying of cannibalistic behaviour. Knowledge about cannibalistic behaviour and the logistics of cannibalism along with environmental enhancement are prerequisites for the mitigation of cannibalism in aquaculture. Also, within the context of strain selection, it is of importance to determine whether cannibals are natural-born killers or just lottery winners. These factors are discussed, chiefly as they apply to intracohort cannibalism. In addition, guidelines are suggested for cannibalistic risk assessment, and methods for mitigation of cannibalism are discussed.

@article{doi101046j13652109200200732x,
    author = "Baras, Etienne and Jobling, Malcolm",
    title = "Dynamics of intracohort cannibalism in cultured fish",
    year = "2002",
    journal = "Aquaculture Research",
    abstract = "Abstract Cannibalism is a frequent phenomenon in fish, especially in culture environments where fish are unable to escape predation via habitat segregation or migration. Not all cultured fish species start to exhibit cannibalism at the same age or size, nor is cannibalism equally intense in different species or life stages. Predator to prey size ratios vary substantially between species and life stages, chiefly because cannibalism is governed by gape size limitations and allometric growth of mouthparts. The development of sense organs, hard body parts, swimming and escape capacities in both the predator and the prey also influence prey size selectivity. The dynamics of cannibalism are influenced by these, as well as by environmental, factors that have effects on feed intake, growth depensation and facilitate or complicate the displaying of cannibalistic behaviour. Knowledge about cannibalistic behaviour and the logistics of cannibalism along with environmental enhancement are prerequisites for the mitigation of cannibalism in aquaculture. Also, within the context of strain selection, it is of importance to determine whether cannibals are natural-born killers or just lottery winners. These factors are discussed, chiefly as they apply to intracohort cannibalism. In addition, guidelines are suggested for cannibalistic risk assessment, and methods for mitigation of cannibalism are discussed.",
    url = "https://doi.org/10.1046/j.1365-2109.2002.00732.x",
    doi = "10.1046/j.1365-2109.2002.00732.x",
    openalex = "W2099452444",
    references = "doi101007bf00042661"
}

The development of the cranial lateral line canals and neuromast organs are described in postembryonic zebrafish (0-80 days postfertilization). Cranial canal development commences several weeks after hatch, is initiated in the vicinity of individual neuromasts, and occurs in four discrete stages that are described histologically. Neuromasts remain in open canal grooves for several weeks during which they dramatically change shape and increase in size by adding hair cells at a rate one-tenth that in the zebrafish inner ear. Scanning electron microscopy demonstrates that neuromasts elongate perpendicular to the canal axis and the axis of hair cell polarization and that they lack a prominent nonsensory cell population surrounding the hair cells-features that make zebrafish neuromasts unusual among fishes. These results demand a reassessment of neuromast and lateral line canal diversity among fishes and highlight the utility of the lateral line system of postembryonic zebrafish for experimental and genetic studies of the development and growth of hair cell epithelia.

@article{doi101002dvdy10385,
    author = "Webb, Jacqueline F. and Shirey, Jonathan E.",
    title = "Postembryonic development of the cranial lateral line canals and neuromasts in zebrafish",
    year = "2003",
    journal = "Developmental Dynamics",
    abstract = "The development of the cranial lateral line canals and neuromast organs are described in postembryonic zebrafish (0-80 days postfertilization). Cranial canal development commences several weeks after hatch, is initiated in the vicinity of individual neuromasts, and occurs in four discrete stages that are described histologically. Neuromasts remain in open canal grooves for several weeks during which they dramatically change shape and increase in size by adding hair cells at a rate one-tenth that in the zebrafish inner ear. Scanning electron microscopy demonstrates that neuromasts elongate perpendicular to the canal axis and the axis of hair cell polarization and that they lack a prominent nonsensory cell population surrounding the hair cells-features that make zebrafish neuromasts unusual among fishes. These results demand a reassessment of neuromast and lateral line canal diversity among fishes and highlight the utility of the lateral line system of postembryonic zebrafish for experimental and genetic studies of the development and growth of hair cell epithelia.",
    url = "https://doi.org/10.1002/dvdy.10385",
    doi = "10.1002/dvdy.10385",
    openalex = "W2061905890",
    references = "doi10100797814612053338, doi10100797814612356063"
}

Osteichthyan and chondrichthyan fish present an astonishing diversity of skeletal and dental tissues that are often difficult to classify into the standard textbook categories of bone, cartilage, dentine and enamel. To address the question of how the tissues of the dermal skeleton evolved from the ancestral situation and gave rise to the diversity actually encountered, we review previous data on the development of a number of dermal skeletal elements (odontodes, teeth and dermal denticles, cranial dermal bones, postcranial dermal plates and scutes, elasmoid and ganoid scales, and fin rays). A comparison of developmental stages at the tissue level usually allows us to identify skeletogenic cell populations as either odontogenic or osteogenic on the basis of the place of formation of their dermal papillae and of the way of deposition of their tissues. Our studies support the evolutionary affinities (1) between odontodes, teeth and denticles, (2) between the ganoid scales of polypterids and the elasmoid scales of teleosts, and (3) to a lesser degree between the different bony elements. There is now ample evidence to ascertain that the tissues of the elasmoid scale are derived from dental and not from bony tissues. This review demonstrates the advantage that can be taken from developmental studies, at the tissue level, to infer evolutionary relationships within the dermal skeleton in chondrichthyans and osteichthyans.

@article{doi101017s1464793102006073,
    author = "Sire, Jean‐Yves and Huysseune, Ann",
    title = "Formation of dermal skeletal and dental tissues in fish: a comparative and evolutionary approach",
    year = "2003",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "Osteichthyan and chondrichthyan fish present an astonishing diversity of skeletal and dental tissues that are often difficult to classify into the standard textbook categories of bone, cartilage, dentine and enamel. To address the question of how the tissues of the dermal skeleton evolved from the ancestral situation and gave rise to the diversity actually encountered, we review previous data on the development of a number of dermal skeletal elements (odontodes, teeth and dermal denticles, cranial dermal bones, postcranial dermal plates and scutes, elasmoid and ganoid scales, and fin rays). A comparison of developmental stages at the tissue level usually allows us to identify skeletogenic cell populations as either odontogenic or osteogenic on the basis of the place of formation of their dermal papillae and of the way of deposition of their tissues. Our studies support the evolutionary affinities (1) between odontodes, teeth and denticles, (2) between the ganoid scales of polypterids and the elasmoid scales of teleosts, and (3) to a lesser degree between the different bony elements. There is now ample evidence to ascertain that the tissues of the elasmoid scale are derived from dental and not from bony tissues. This review demonstrates the advantage that can be taken from developmental studies, at the tissue level, to infer evolutionary relationships within the dermal skeleton in chondrichthyans and osteichthyans.",
    url = "https://doi.org/10.1017/s1464793102006073",
    doi = "10.1017/s1464793102006073",
    openalex = "W2036850921",
    references = "doi101002jmor1051660303, doi10100797814615696887, doi101111j1469185x1999tb00045x, doi101111j160007221998tb02212x"
}

Homology is at the foundation of comparative studies in biology at all levels from genes to phenotypes. Homology is similarity because of common descent and ancestry, homoplasy is similarity arrived at via independent evolution. However, given that there is but one tree of life, all organisms, and therefore all features of organisms, share some degree of relationship and similarity one to another. That sharing may be similarity or even identity of structure and the sharing of a most recent common ancestor--as in the homology of the arms of humans and apes--or it may reflect some (often small) degree of similarity, such as that between the wings of insects and the wings of birds, groups whose shared ancestor lies deep within the evolutionary history of the Metazoa. It may reflect sharing of entire developmental pathways, partial sharing, or divergent pathways. This review compares features classified as homologous with the classes of features normally grouped as homoplastic, the latter being convergence, parallelism, reversals, rudiments, vestiges, and atavisms. On the one hand, developmental mechanisms may be conserved, even when a complete structure does not form (rudiments, vestiges), or when a structure appears only in some individuals (atavisms). On the other hand, different developmental mechanisms can produce similar (homologous) features. Joint examination of nearness of relationship and degree of shared development reveals a continuum within an expanded category of homology, extending from homology --> reversals --> rudiments --> vestiges --> atavisms --> parallelism, with convergence as the only class of homoplasy, an idea that turns out to be surprisingly old. This realignment provides a glimmer of a way to bridge phylogenetic and developmental approaches to homology and homoplasy, a bridge that should provide a key pillar for evolutionary developmental biology (evo-devo). It will not, and in a practical sense cannot, alter how homoplastic features are identified in phylogenetic analyses. But seeing rudiments, reversals, vestiges, atavisms and parallelism as closer to homology than to homoplasy should guide us toward searching for the common elements underlying the formation of the phenotype (what some have called the deep homology of genetic and/or cellular mechanisms), rather than discussing features in terms of shared or independent evolution.

@article{doi101017s1464793102006097,
    author = "Hall, Brian K.",
    title = "Descent with modification: the unity underlying homology and homoplasy as seen through an analysis of development and evolution",
    year = "2003",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "Homology is at the foundation of comparative studies in biology at all levels from genes to phenotypes. Homology is similarity because of common descent and ancestry, homoplasy is similarity arrived at via independent evolution. However, given that there is but one tree of life, all organisms, and therefore all features of organisms, share some degree of relationship and similarity one to another. That sharing may be similarity or even identity of structure and the sharing of a most recent common ancestor--as in the homology of the arms of humans and apes--or it may reflect some (often small) degree of similarity, such as that between the wings of insects and the wings of birds, groups whose shared ancestor lies deep within the evolutionary history of the Metazoa. It may reflect sharing of entire developmental pathways, partial sharing, or divergent pathways. This review compares features classified as homologous with the classes of features normally grouped as homoplastic, the latter being convergence, parallelism, reversals, rudiments, vestiges, and atavisms. On the one hand, developmental mechanisms may be conserved, even when a complete structure does not form (rudiments, vestiges), or when a structure appears only in some individuals (atavisms). On the other hand, different developmental mechanisms can produce similar (homologous) features. Joint examination of nearness of relationship and degree of shared development reveals a continuum within an expanded category of homology, extending from homology --> reversals --> rudiments --> vestiges --> atavisms --> parallelism, with convergence as the only class of homoplasy, an idea that turns out to be surprisingly old. This realignment provides a glimmer of a way to bridge phylogenetic and developmental approaches to homology and homoplasy, a bridge that should provide a key pillar for evolutionary developmental biology (evo-devo). It will not, and in a practical sense cannot, alter how homoplastic features are identified in phylogenetic analyses. But seeing rudiments, reversals, vestiges, atavisms and parallelism as closer to homology than to homoplasy should guide us toward searching for the common elements underlying the formation of the phenotype (what some have called the deep homology of genetic and/or cellular mechanisms), rather than discussing features in terms of shared or independent evolution.",
    url = "https://doi.org/10.1017/s1464793102006097",
    doi = "10.1017/s1464793102006097",
    openalex = "W2168524476",
    references = "doi10100797814899175155, doi1010079789401579261, doi1016680003156920000400718bgadbt20co2, doi1023071377078, doi1023072992444, openalexw1511255518, openalexw1593551567, openalexw1600651929, openalexw2163836228, openalexw635257420"
}

In the first part of this paper we review current knowledge regarding fish scales, focusing on elasmoid scales, the only type found in two model species, the zebrafish and the medaka. After reviewing the structure of scales and their evolutionary origin, we describe the formation of the squamation pattern. The regularity of this process suggests a pre-patterning of the skin before scale initiation. We then summarise the dynamics of scale development on the basis of morphological observations. In the absence of molecular data, these observations support the existence of genetic cascades involved in the control of scale development. In the second part of this paper, we illustrate the potential that scale development offers as a model to study organogenesis mediated by epithelial-mesenchymal interactions. Using the zebrafish (Danio rerio), we have combined alizarin red staining, light and transmission electron microscopy and in situ hybridisation using an anti-sense RNA probe for the sonic hedgehog (shh) gene. Scales develop late in ontogeny (30 days post-fertilisation) and close to the epidermal cover. Only cells of the basal epidermal layer express shh. Transcripts are first detected after the scale papillae have formed. Thus, shh is not involved in the mechanisms controlling squamation patterning and scale initiation. As the scales enlarge, shh expression is progressively restricted to a subset of basal epidermal cells located in the region that overlies their posterior field. This pattern of expression suggests that shh may be involved in the control of scale morphogenesis and differentiation in relationship with the formation of the epidermal fold in the posterior region.

@article{doi101387ijdb15272389,
    author = "Sire, Jean‐Yves and Akimenko, Marie‐Andrée",
    title = "Scale development in fish: a review, with description of sonic hedgehog (shh) expression in the zebrafish (Danio rerio).",
    year = "2004",
    journal = "The International Journal of Developmental Biology",
    abstract = "In the first part of this paper we review current knowledge regarding fish scales, focusing on elasmoid scales, the only type found in two model species, the zebrafish and the medaka. After reviewing the structure of scales and their evolutionary origin, we describe the formation of the squamation pattern. The regularity of this process suggests a pre-patterning of the skin before scale initiation. We then summarise the dynamics of scale development on the basis of morphological observations. In the absence of molecular data, these observations support the existence of genetic cascades involved in the control of scale development. In the second part of this paper, we illustrate the potential that scale development offers as a model to study organogenesis mediated by epithelial-mesenchymal interactions. Using the zebrafish (Danio rerio), we have combined alizarin red staining, light and transmission electron microscopy and in situ hybridisation using an anti-sense RNA probe for the sonic hedgehog (shh) gene. Scales develop late in ontogeny (30 days post-fertilisation) and close to the epidermal cover. Only cells of the basal epidermal layer express shh. Transcripts are first detected after the scale papillae have formed. Thus, shh is not involved in the mechanisms controlling squamation patterning and scale initiation. As the scales enlarge, shh expression is progressively restricted to a subset of basal epidermal cells located in the region that overlies their posterior field. This pattern of expression suggests that shh may be involved in the control of scale morphogenesis and differentiation in relationship with the formation of the epidermal fold in the posterior region.",
    url = "https://doi.org/10.1387/ijdb.15272389",
    doi = "10.1387/ijdb.15272389",
    openalex = "W2094026255",
    references = "doi101002jmor1051660303, doi10100797814615696887, doi105962bhltitle4275"
}

Historically, philosophers of biology have tended to sidestep the problem of development by focusing primarily on evolutionary biology and, more recently, on molecular biology and genetics. Quite often too, development has been misunderstood as simply, or even primarily, a matter of gene activation and regulation. Nowadays a growing number of philosophers of science are focusing their analyses on the complexities of development, and in Embryology, Epigenesis and Evolution Jason Scott Robert explores the nature of development against current trends in biological theory and practice and looks at the interrelations between development and evolution (evo-devo), an area of resurgent biological interest. Clearly written, this book should be of interest to students and professionals in the philosophy of science and the philosophy of biology.

@article{doi105860choice422215,
    title = "Embryology, epigenesis, and evolution: taking development seriously",
    year = "2004",
    journal = "Choice Reviews Online",
    abstract = "Historically, philosophers of biology have tended to sidestep the problem of development by focusing primarily on evolutionary biology and, more recently, on molecular biology and genetics. Quite often too, development has been misunderstood as simply, or even primarily, a matter of gene activation and regulation. Nowadays a growing number of philosophers of science are focusing their analyses on the complexities of development, and in Embryology, Epigenesis and Evolution Jason Scott Robert explores the nature of development against current trends in biological theory and practice and looks at the interrelations between development and evolution (evo-devo), an area of resurgent biological interest. Clearly written, this book should be of interest to students and professionals in the philosophy of science and the philosophy of biology.",
    url = "https://doi.org/10.5860/choice.42-2215",
    doi = "10.5860/choice.42-2215",
    openalex = "W563979555",
    references = "doi101038276565a0, doi10103835057062, doi101046j1525142x2001003002047x, doi101098rspb19790086, doi101126science1058040, doi1023072026953, doi1023072576242, doi1023072678463, doi105860choice396411, openalexw2506868775, openalexw2624262714, openalexw3135630760"
}

@article{doi101007s1106800583531,
    author = "Hansen, Anne and Zielinski, Barbara S.",
    title = "Diversity in the olfactory epithelium of bony fishes: Development, lamellar arrangement, sensory neuron cell types and transduction components",
    year = "2005",
    journal = "Journal of Neurocytology",
    url = "https://doi.org/10.1007/s11068-005-8353-1",
    doi = "10.1007/s11068-005-8353-1",
    openalex = "W2056529429",
    references = "doi101002cne920200404, doi101111j109636421932tb01553x"
}

published data on the diversity, life history, ecology, and status of freshwater and euryhaline elasmobranchs was reviewed in the context of anthropogenic threats and principles of conservation biology. at least 171 species of elasmobranch, representing 68 genera and 34 families, are recorded from fresh or estuarine waters. of these, over half are marginal in estuaries, less than one-tenth are euryhaline, and one-fifth are obligate in fresh water. obligate freshwater elasmobranchs are dominated by myliobatoid stingrays, of which two-thirds are potamotrygonids endemic to atlantic drainages of south america. freshwater and euryhaline elasmobranchs adhere to strongly k-selected life histories and feed at high trophic levels, similar to those of their marine relatives. however, freshwater and euryhaline elasmobranchs are also subject to habitat constraints, notably more limited volume and physicochemical variability than the ocean, that may render them more vulnerable than marine elasmobranchs to the effects of human activities. the greatest diversity and abundance of freshwater and euryhaline elasmobranchs occur in tropical countries with enormous and rapidly increasing human populations, notably south america, west africa, and south-east asia. knowledge of the biology, distribution, ecology, and status of freshwater and euryhaline elasmobranchs is frustrated by unresolved taxonomic problems, which are briefly summarized. to clarify selected issues in the conservation of freshwater and euryhaline elasmobranchs, special attention is given to sharks of the genus glyphis, pristids, and potamotrygonids. to foster live release when possible as well as prevent discard of specimens and loss of data, an illustrated key to differentiate carcharhinus from glyphis sharks is provided. obligate freshwater elasmobranchs with limited geographic ranges are deemed most vulnerable to extinction, but euryhaline elasmobranchs that require access to the sea to breed are also at significant risk. based on the foregoing data and principles of conservation biology, suggested action plans for the conservation of freshwater and euryhaline elasmobranchs and the conservation of freshwater habitats are provided.

@article{doi101017s0025315405012105,
    author = "Martin, Ralph",
    title = "conservation of freshwater and euryhaline elasmobranchs: a review",
    year = "2005",
    journal = "Journal of the Marine Biological Association of the United Kingdom",
    abstract = "published data on the diversity, life history, ecology, and status of freshwater and euryhaline elasmobranchs was reviewed in the context of anthropogenic threats and principles of conservation biology. at least 171 species of elasmobranch, representing 68 genera and 34 families, are recorded from fresh or estuarine waters. of these, over half are marginal in estuaries, less than one-tenth are euryhaline, and one-fifth are obligate in fresh water. obligate freshwater elasmobranchs are dominated by myliobatoid stingrays, of which two-thirds are potamotrygonids endemic to atlantic drainages of south america. freshwater and euryhaline elasmobranchs adhere to strongly k-selected life histories and feed at high trophic levels, similar to those of their marine relatives. however, freshwater and euryhaline elasmobranchs are also subject to habitat constraints, notably more limited volume and physicochemical variability than the ocean, that may render them more vulnerable than marine elasmobranchs to the effects of human activities. the greatest diversity and abundance of freshwater and euryhaline elasmobranchs occur in tropical countries with enormous and rapidly increasing human populations, notably south america, west africa, and south-east asia. knowledge of the biology, distribution, ecology, and status of freshwater and euryhaline elasmobranchs is frustrated by unresolved taxonomic problems, which are briefly summarized. to clarify selected issues in the conservation of freshwater and euryhaline elasmobranchs, special attention is given to sharks of the genus glyphis, pristids, and potamotrygonids. to foster live release when possible as well as prevent discard of specimens and loss of data, an illustrated key to differentiate carcharhinus from glyphis sharks is provided. obligate freshwater elasmobranchs with limited geographic ranges are deemed most vulnerable to extinction, but euryhaline elasmobranchs that require access to the sea to breed are also at significant risk. based on the foregoing data and principles of conservation biology, suggested action plans for the conservation of freshwater and euryhaline elasmobranchs and the conservation of freshwater habitats are provided.",
    url = "https://doi.org/10.1017/s0025315405012105",
    doi = "10.1017/s0025315405012105",
    openalex = "W2096292907",
    references = "doi101111j109636421996tb02189x, openalexw1511461941"
}

The branchial arches are meristic vertebrate structures, being metameric both between each other within the rostrocaudal series along the ventrocephalic surface of the embryonic head and within each individual arch: thus, just as each branchial arch must acquire a unique identity along the rostrocaudal axis, each structure within the proximodistal axis of an arch must also acquire a unique identity. It is believed that regional specification of metameric structures is controlled by the nested expression of related genes resulting in a regional code, a principal that is though to be demonstrated by the regulation of rostrocaudal axis development in animals exerted by the nested HOM-C/Hox homeobox genes. The nested expression pattern of the Dlx genes within the murine branchial arch ectomesenchyme has more recently led to the proposal of a Dlx code for the regional specification along the proximodistal axis of the branchial arches (i.e. it establishes intra-arch identity). This review re-examines this hypothesis, and presents new work on an allelic series of Dlx loss-of-function mouse mutants that includes various combinations of Dlx1, Dlx2, Dlx3, Dlx5 and Dlx6. Although we confirm fundamental aspects of the hypothesis, we further report a number of novel findings. First, contrary to initial reports, Dlx1, Dlx2 and Dlx1/2 heterozygotes exhibit alterations of branchial arch structures and Dlx2-/- and Dlx1/2-/- mutants have slight alterations of structures derived from the distal portions of their branchial arches. Second, we present evidence for a role for murine Dlx3 in the development of the branchial arches. Third, analysis of compound Dlx mutants reveals four grades of mandibular arch transformations and that the genetic interactions of cis first-order (e.g. Dlx5 and Dlx6), trans second-order (e.g. Dlx5 and Dlx2) and trans third-order paralogues (e.g. Dlx5 and Dlx1) result in significant and distinct morphological differences in mandibular arch development. We conclude by integrating functions of the Dlx genes within the context of a hypothesized general mechanism for the establishment of pattern and polarity in the first branchial arch of gnathostomes that includes regionally secreted growth factors such as Fgf8 and Bmp and other transcription factors such as Msx1, and is consistent both with the structure of the conserved gnathostome jaw bauplan and the elaboration of this bauplan to meet organismal end-point designs.

@article{doi101111j14697580200500487x,
    author = "Depew, Michael J. and Simpson, Carol A. and Morasso, María I. and Rubenstein, John L.R.",
    title = "Reassessing the Dlx code: the genetic regulation of branchial arch skeletal pattern and development",
    year = "2005",
    journal = "Journal of Anatomy",
    abstract = "The branchial arches are meristic vertebrate structures, being metameric both between each other within the rostrocaudal series along the ventrocephalic surface of the embryonic head and within each individual arch: thus, just as each branchial arch must acquire a unique identity along the rostrocaudal axis, each structure within the proximodistal axis of an arch must also acquire a unique identity. It is believed that regional specification of metameric structures is controlled by the nested expression of related genes resulting in a regional code, a principal that is though to be demonstrated by the regulation of rostrocaudal axis development in animals exerted by the nested HOM-C/Hox homeobox genes. The nested expression pattern of the Dlx genes within the murine branchial arch ectomesenchyme has more recently led to the proposal of a Dlx code for the regional specification along the proximodistal axis of the branchial arches (i.e. it establishes intra-arch identity). This review re-examines this hypothesis, and presents new work on an allelic series of Dlx loss-of-function mouse mutants that includes various combinations of Dlx1, Dlx2, Dlx3, Dlx5 and Dlx6. Although we confirm fundamental aspects of the hypothesis, we further report a number of novel findings. First, contrary to initial reports, Dlx1, Dlx2 and Dlx1/2 heterozygotes exhibit alterations of branchial arch structures and Dlx2-/- and Dlx1/2-/- mutants have slight alterations of structures derived from the distal portions of their branchial arches. Second, we present evidence for a role for murine Dlx3 in the development of the branchial arches. Third, analysis of compound Dlx mutants reveals four grades of mandibular arch transformations and that the genetic interactions of cis first-order (e.g. Dlx5 and Dlx6), trans second-order (e.g. Dlx5 and Dlx2) and trans third-order paralogues (e.g. Dlx5 and Dlx1) result in significant and distinct morphological differences in mandibular arch development. We conclude by integrating functions of the Dlx genes within the context of a hypothesized general mechanism for the establishment of pattern and polarity in the first branchial arch of gnathostomes that includes regionally secreted growth factors such as Fgf8 and Bmp and other transcription factors such as Msx1, and is consistent both with the structure of the conserved gnathostome jaw bauplan and the elaboration of this bauplan to meet organismal end-point designs.",
    url = "https://doi.org/10.1111/j.1469-7580.2005.00487.x",
    doi = "10.1111/j.1469-7580.2005.00487.x",
    openalex = "W1602845636",
    references = "doi101007978146122784737, doi1010970000505319311100000026, doi105962bhltitle6408, openalexw1568405999"
}

Amphioxus neuroanatomy is important not just in its own right but also for the insights it provides regarding the evolutionary origin and basic organization of the vertebrate nervous system. This review summarizes the overall layout of the central nervous system (CNS), peripheral nerves, and nerve plexuses in amphioxus, and what is currently known of their histology and cell types, with special attention to new information on the anterior nerve cord. The intercalated region (IR) is of special functional and evolutionary interest. It extends caudally to the end of somite 4, traditionally considered the limit of the brain-like region of the amphioxus CNS, and is notable for the presence of a number of migrated cell groups. Unlike most other neurons in the cord, these migrated cells detach from the ventricular lumen and move into the adjacent neuropile, much as developing neurons do in vertebrates. The larval nervous system is also considered, as there is a wealth of new data on the organization and cell types of the anterior nerve cord in young larvae, based on detailed electron microscopical analyses and nerve tracing studies, and an emerging consensus regarding how this region relates to the vertebrate brain. Much less is known about the intervening period of the life history, i.e., the period between the young larva and the adult, but a great deal of neural development must occur during this time to generate a fully mature nervous system. It is especially interesting that the vertebrate counterparts of at least some postembryonic events of amphioxus neurogenesis occur, in vertebrates, in the embryo. The implication is that the whole of the postembryonic phase of neural development in amphioxus needs to be considered when making phylogenetic comparisons. Yet this is a period about which almost nothing is known. Considering this, plus the number of new molecular and immunocytochemical techniques now available to researchers, there is no shortage of worthwhile research topics using amphioxus, of whatever stage, as a subject.

@article{doi101139z04163,
    author = "Wicht, Helmut and Lacalli, Thurston C.",
    title = "The nervous system of amphioxus: structure, development, and evolutionary significance",
    year = "2005",
    journal = "Canadian Journal of Zoology",
    abstract = "Amphioxus neuroanatomy is important not just in its own right but also for the insights it provides regarding the evolutionary origin and basic organization of the vertebrate nervous system. This review summarizes the overall layout of the central nervous system (CNS), peripheral nerves, and nerve plexuses in amphioxus, and what is currently known of their histology and cell types, with special attention to new information on the anterior nerve cord. The intercalated region (IR) is of special functional and evolutionary interest. It extends caudally to the end of somite 4, traditionally considered the limit of the brain-like region of the amphioxus CNS, and is notable for the presence of a number of migrated cell groups. Unlike most other neurons in the cord, these migrated cells detach from the ventricular lumen and move into the adjacent neuropile, much as developing neurons do in vertebrates. The larval nervous system is also considered, as there is a wealth of new data on the organization and cell types of the anterior nerve cord in young larvae, based on detailed electron microscopical analyses and nerve tracing studies, and an emerging consensus regarding how this region relates to the vertebrate brain. Much less is known about the intervening period of the life history, i.e., the period between the young larva and the adult, but a great deal of neural development must occur during this time to generate a fully mature nervous system. It is especially interesting that the vertebrate counterparts of at least some postembryonic events of amphioxus neurogenesis occur, in vertebrates, in the embryo. The implication is that the whole of the postembryonic phase of neural development in amphioxus needs to be considered when making phylogenetic comparisons. Yet this is a period about which almost nothing is known. Considering this, plus the number of new molecular and immunocytochemical techniques now available to researchers, there is no shortage of worthwhile research topics using amphioxus, of whatever stage, as a subject.",
    url = "https://doi.org/10.1139/z04-163",
    doi = "10.1139/z04-163",
    openalex = "W2092757339",
    references = "anadn1998distribution, bone1959the, bone1961the, castro2003distribution, dogiel1903das, doi101002cne901150105, doi101002jmor1050540103, doi1010079783642182624, doi101007bf00348527, doi101007bf02028391, doi101016jydbio200604457, doi101016s0022532062800070, doi101098rstb19940059, doi101098rstb19960022, doi101111j146363951995tb00986x, doi101139z04160, doi101159000079744, doi101159000147530, doi101242dev125142701, doi101242jcss310052509, doi1023071535762, doi103166jds1391111, doi105962bhltitle159385, doi105962bhltitle55924, flood1974histochemistry, holmes1953the, openalexw2394638245, openalexw659399033, ruiz1991the, stokes1995ciliary"
}

A quantitative comparison was made of both relative brain size (encephalization) and the relative development of five brain area of pelagic sharks and teleosts. Two integration areas (the telencephalon and the corpus cerebellum) and three sensory brain areas (the olfactory bulbs, optic tectum and octavolateralis area, which receive primary projections from the olfactory epithelium, eye and octavolateralis senses, respectively), in four species of pelagic shark and six species of pelagic teleost were investigated. The relative proportions of the three sensory brain areas were assessed as a proportion of the total ‘sensory brain’, while the two integration areas were assessed relative to the sensory brain. The allometric analysis of relative brain size revealed that pelagic sharks had larger brains than pelagic teleosts. The volume of the telencephalon was significantly larger in the sharks, while the corpus cerebellum was also larger and more heavily foliated in these animals. There were also significant differences in the relative development of the sensory brain areas between the two groups, with the sharks having larger olfactory bulbs and octavolateralis areas, whilst the teleosts had larger optic tecta. Cluster analysis performed on the sensory brain areas data confirmed the differences in the composition of the sensory brain in sharks and teleosts and indicated that these two groups of pelagic fishes had evolved different sensory strategies to cope with the demands of life in the open ocean.

@article{doi101111j00221112200600940x,
    author = "Lisney, Thomas J. and Collin, Shaun P.",
    title = "Brain morphology in large pelagic fishes: a comparison between sharks and teleosts",
    year = "2006",
    journal = "Journal of Fish Biology",
    abstract = "A quantitative comparison was made of both relative brain size (encephalization) and the relative development of five brain area of pelagic sharks and teleosts. Two integration areas (the telencephalon and the corpus cerebellum) and three sensory brain areas (the olfactory bulbs, optic tectum and octavolateralis area, which receive primary projections from the olfactory epithelium, eye and octavolateralis senses, respectively), in four species of pelagic shark and six species of pelagic teleost were investigated. The relative proportions of the three sensory brain areas were assessed as a proportion of the total ‘sensory brain’, while the two integration areas were assessed relative to the sensory brain. The allometric analysis of relative brain size revealed that pelagic sharks had larger brains than pelagic teleosts. The volume of the telencephalon was significantly larger in the sharks, while the corpus cerebellum was also larger and more heavily foliated in these animals. There were also significant differences in the relative development of the sensory brain areas between the two groups, with the sharks having larger olfactory bulbs and octavolateralis areas, whilst the teleosts had larger optic tecta. Cluster analysis performed on the sensory brain areas data confirmed the differences in the composition of the sensory brain in sharks and teleosts and indicated that these two groups of pelagic fishes had evolved different sensory strategies to cope with the demands of life in the open ocean.",
    url = "https://doi.org/10.1111/j.0022-1112.2006.00940.x",
    doi = "10.1111/j.0022-1112.2006.00940.x",
    openalex = "W2057916053",
    references = "doi101007978364218262412"
}

We described the developmental stages for the embryonic, larval and early juvenile periods of Nile tilapia Oreochromis niloticus to elucidate sequential events of craniofacial development. Craniofacial development of cichlids, especially differentiation and morphogenesis of the pharyngeal skeleton, progresses until about 30 days postfertilization (dpf). Because there is no comprehensive report describing the sequential processes of craniofacial development up to 30 dpf, we newly defined 32 stages using a numbered staging system. For embryonic development, we defined 18 stages (stages 1-18), which were grouped into seven periods named the zygote, cleavage, blastula, gastrula, segmentation, pharyngula and hatching periods. For larval development, we defined seven stages (stages 19-25), which were grouped into two periods, early larval and late larval. For juvenile development until 30 dpf, we defined seven stages (stages 26-32) in the early juvenile period. This developmental staging system for Nile tilapia O. niloticus will benefit researchers investigating skeletogenesis throughout tilapia ontogeny and will also facilitate comparative evolutionary developmental biology studies of haplochromine cichlids, which comprise the species flocks of Lakes Malawi and Victoria.

@article{doi101111j1440169x200700926x,
    author = "Fujimura, Koji and Okada, Norihiro",
    title = "Development of the embryo, larva and early juvenile of Nile tilapia Oreochromis niloticus (Pisces: Cichlidae). Developmental staging system",
    year = "2007",
    journal = "Development Growth \& Differentiation",
    abstract = "We described the developmental stages for the embryonic, larval and early juvenile periods of Nile tilapia Oreochromis niloticus to elucidate sequential events of craniofacial development. Craniofacial development of cichlids, especially differentiation and morphogenesis of the pharyngeal skeleton, progresses until about 30 days postfertilization (dpf). Because there is no comprehensive report describing the sequential processes of craniofacial development up to 30 dpf, we newly defined 32 stages using a numbered staging system. For embryonic development, we defined 18 stages (stages 1-18), which were grouped into seven periods named the zygote, cleavage, blastula, gastrula, segmentation, pharyngula and hatching periods. For larval development, we defined seven stages (stages 19-25), which were grouped into two periods, early larval and late larval. For juvenile development until 30 dpf, we defined seven stages (stages 26-32) in the early juvenile period. This developmental staging system for Nile tilapia O. niloticus will benefit researchers investigating skeletogenesis throughout tilapia ontogeny and will also facilitate comparative evolutionary developmental biology studies of haplochromine cichlids, which comprise the species flocks of Lakes Malawi and Victoria.",
    url = "https://doi.org/10.1111/j.1440-169x.2007.00926.x",
    doi = "10.1111/j.1440-169x.2007.00926.x",
    openalex = "W1795668487",
    references = "doi101002jez1402670309, doi101139f75196"
}

@article{doi101016jcbpa200909031,
    author = "Speers‐Roesch, Ben and Treberg, Jason R.",
    title = "The unusual energy metabolism of elasmobranch fishes",
    year = "2009",
    journal = "Comparative Biochemistry and Physiology Part A Molecular \& Integrative Physiology",
    url = "https://doi.org/10.1016/j.cbpa.2009.09.031",
    doi = "10.1016/j.cbpa.2009.09.031",
    openalex = "W2007450572",
    references = "doi101007978940113194013, doi101007bf00007454, doi101111j1469185x1936tb00497x, doi101201b118678"
}

@article{doi101007s1075001001203,
    author = "Logan, John M. and Lutcavage, Molly E.",
    title = "Stable isotope dynamics in elasmobranch fishes",
    year = "2010",
    journal = "Hydrobiologia",
    url = "https://doi.org/10.1007/s10750-010-0120-3",
    doi = "10.1007/s10750-010-0120-3",
    openalex = "W1993685048",
    references = "doi101111j1469185x1936tb00497x"
}

In most species, fish spermatozoa activate their motility on contact with the external medium (sea or fresh water depending of their reproductive habitat). Their flagella immediately develop waves propagated at high beat frequency (up to 70 beats s(-1)), which propel these sperm cells at high velocity (6-10 mm min(-1)), but for a quite short period of time, usually limited to minutes. Their specific inability to restore their energy content (mostly adenosine triphosphate) fast enough relatively to their high rate of energy consumption by flagellar contributes mainly to the activity arrest of motility, as the spermatozoa need to rely on early accumulated energy prior to activation. This review of the published data explains the present understanding of physico-chemical mechanisms by which flagellar motility is activated (mostly through osmotic and ionic regulation) and then propels sperm cells at speed. It aims also to describe the gradual arrest of their motility much of which occurs within a few minutes.

@article{doi101111j10958649200902504x,
    author = "Cosson, J.",
    title = "Frenetic activation of fish spermatozoa flagella entails short‐term motility, portending their precocious decadence",
    year = "2010",
    journal = "Journal of Fish Biology",
    abstract = "In most species, fish spermatozoa activate their motility on contact with the external medium (sea or fresh water depending of their reproductive habitat). Their flagella immediately develop waves propagated at high beat frequency (up to 70 beats s(-1)), which propel these sperm cells at high velocity (6-10 mm min(-1)), but for a quite short period of time, usually limited to minutes. Their specific inability to restore their energy content (mostly adenosine triphosphate) fast enough relatively to their high rate of energy consumption by flagellar contributes mainly to the activity arrest of motility, as the spermatozoa need to rely on early accumulated energy prior to activation. This review of the published data explains the present understanding of physico-chemical mechanisms by which flagellar motility is activated (mostly through osmotic and ionic regulation) and then propels sperm cells at speed. It aims also to describe the gradual arrest of their motility much of which occurs within a few minutes.",
    url = "https://doi.org/10.1111/j.1095-8649.2009.02504.x",
    doi = "10.1111/j.1095-8649.2009.02504.x",
    openalex = "W2057524967",
    references = "openalexw612600151"
}

@book{doi105962bhltitle32902,
    author = "Dean, Bashford",
    title = "Chimæroid Fishes and Their Development",
    year = "2010",
    booktitle = "Biodiversity Heritage Library (Smithsonian Institution)",
    url = "https://doi.org/10.5962/bhl.title.32902",
    doi = "10.5962/bhl.title.32902",
    openalex = "W564594173"
}

Skeletal muscles exert diverse functions, enabling both crushing with great force and movement with exquisite precision. A remarkably distinct repertoire of genes and ontological features characterise this tissue, and recent evidence has shown that skeletal muscles of the head, the craniofacial muscles, are evolutionarily, morphologically and molecularly distinct from those of the trunk. Here, we review the molecular basis of craniofacial muscle development and discuss how this process is different to trunk and limb muscle development. Through evolutionary comparisons of primitive chordates (such as amphioxus) and jawless vertebrates (such as lampreys) with jawed vertebrates, we also provide some clues as to how this dichotomy arose.

@article{doi101242dev040972,
    author = "Sambasivan, Ramkumar and Kuratani, Shigeru and Tajbakhsh, Shahragim",
    title = "An eye on the head: the development and evolution of craniofacial muscles",
    year = "2011",
    journal = "Development",
    abstract = "Skeletal muscles exert diverse functions, enabling both crushing with great force and movement with exquisite precision. A remarkably distinct repertoire of genes and ontological features characterise this tissue, and recent evidence has shown that skeletal muscles of the head, the craniofacial muscles, are evolutionarily, morphologically and molecularly distinct from those of the trunk. Here, we review the molecular basis of craniofacial muscle development and discuss how this process is different to trunk and limb muscle development. Through evolutionary comparisons of primitive chordates (such as amphioxus) and jawless vertebrates (such as lampreys) with jawed vertebrates, we also provide some clues as to how this dichotomy arose.",
    url = "https://doi.org/10.1242/dev.040972",
    doi = "10.1242/dev.040972",
    openalex = "W2004543760",
    references = "doi101006dbio19999266, doi101046j1525142x199999019x, doi1010970000505319311100000026"
}

Invasive freshwater fish represent a major threat to biodiversity. Here, we first demonstrate the dramatic, human-mediated range expansion of the Trinidadian guppy (Poecilia reticulata), an invasive fish with a reputation for negatively impacting native freshwater communities. Next, we explore possible mechanisms that might explain successful global establishment of this species. Guppies, along with some other notable invasive fish species such as mosquitofish (Gambusia spp.), have reproductive adaptations to ephemeral habitats that may enable introductions of very small numbers of founders to succeed. The remarkable ability of single pregnant guppies to routinely establish viable populations is demonstrated using a replicated mesocosm set up. In 86% of cases, these populations persisted for two years (the duration of the experiment). Establishment success was independent of founder origin (high and low predation habitats), and there was no loss of behavioural performance amongst mesocosm juveniles. Behavioural "signatures" of the founding locality were, however, evident in mesocosm fish. Our results demonstrate that introductions consisting of a single individual can lead to thriving populations of this invasive fish and suggest that particular caution should be exercised when introducing this species, or other livebearers, to natural water bodies.

@article{doi101371journalpone0024416,
    author = "Deacon, Amy E. and Ramnarine, Indar W. and Magurran, Anne E.",
    title = "How Reproductive Ecology Contributes to the Spread of a Globally Invasive Fish",
    year = "2011",
    journal = "PLoS ONE",
    abstract = {Invasive freshwater fish represent a major threat to biodiversity. Here, we first demonstrate the dramatic, human-mediated range expansion of the Trinidadian guppy (Poecilia reticulata), an invasive fish with a reputation for negatively impacting native freshwater communities. Next, we explore possible mechanisms that might explain successful global establishment of this species. Guppies, along with some other notable invasive fish species such as mosquitofish (Gambusia spp.), have reproductive adaptations to ephemeral habitats that may enable introductions of very small numbers of founders to succeed. The remarkable ability of single pregnant guppies to routinely establish viable populations is demonstrated using a replicated mesocosm set up. In 86\% of cases, these populations persisted for two years (the duration of the experiment). Establishment success was independent of founder origin (high and low predation habitats), and there was no loss of behavioural performance amongst mesocosm juveniles. Behavioural "signatures" of the founding locality were, however, evident in mesocosm fish. Our results demonstrate that introductions consisting of a single individual can lead to thriving populations of this invasive fish and suggest that particular caution should be exercised when introducing this species, or other livebearers, to natural water bodies.},
    url = "https://doi.org/10.1371/journal.pone.0024416",
    doi = "10.1371/journal.pone.0024416",
    openalex = "W2171862242",
    references = "doi101007bf00042661"
}

Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the "bush at the top of the tree" that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the "Second Age of Fishes."

@article{doi101073pnas1206625109,
    author = "Near, Thomas J. and Eytan, Ron I. and Dornburg, Alex and Kuhn, Kristen L. and Moore, Jon A. and Davis, Matthew P. and Wainwright, Peter C. and Friedman, Matt and Smith, W. Leo",
    title = "Resolution of ray-finned fish phylogeny and timing of diversification",
    year = "2012",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the "bush at the top of the tree" that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the "Second Age of Fishes."},
    url = "https://doi.org/10.1073/pnas.1206625109",
    doi = "10.1073/pnas.1206625109",
    openalex = "W2081778808",
    references = "doi101016b9780126709506500138, doi101016s1055790302003329, doi101073pnas0811087106, doi101093bioinformaticsbtl446, doi101093bioinformaticsbtq228, doi101093oso97801985404720010001, doi101111j14754983201201165x, doi101126science1157704, doi101126science1211028, doi101186147121487214, doi101371journalpbio0040088, doi1023072412685, openalexw653978695"
}

It is a widely accepted view that neural development can reflect morphological adaptations and sensory specializations. The aim of this review is to give a broad overview of the current status of brain data available for cartilaginous fishes and examine how perspectives on allometric scaling of brain size across this group of fishes has changed within the last 50 years with the addition of new data and more rigorous statistical analyses. The current knowledge of neuroanatomy in cartilaginous fishes is reviewed and data on brain size (encephalization, n = 151) and interspecific variation in brain organization (n = 84) has been explored to ascertain scaling relationships across this clade. It is determined whether similar patterns of brain organization, termed cerebrotypes, exist in species that share certain lifestyle characteristics. Clear patterns of brain organization exist across cartilaginous fishes, irrespective of phylogenetic grouping and, although this study was not a functional analysis, it provides further evidence that chondrichthyan brain structures might have developed in conjunction with specific behaviours or enhanced cognitive capabilities. Larger brains, with well-developed telencephala and large, highly foliated cerebella are reported in species that occupy complex reef or oceanic habitats, potentially identifying a reef-associated cerebrotype. In contrast, benthic and benthopelagic demersal species comprise the group with the smallest brains, with a relatively reduced telencephalon and a smooth cerebellar corpus. There is also evidence herein of a bathyal cerebrotype; deep-sea benthopelagic sharks possess relatively small brains and show a clear relative hypertrophy of the medulla oblongata. Despite the patterns observed and documented, significant gaps in the literature have been highlighted. Brain mass data are only currently available on c. 16% of all chondrichthyan species, and only 8% of species have data available on their brain organization, with far less on subsections of major brain areas that receive distinct sensory input. The interspecific variability in brain organization further stresses the importance of performing functional studies on a greater range of species. Only an expansive data set, comprised of species that span a variety of habitats and taxonomic groups, with widely disparate behavioural repertoires, combined with further functional analyses, will help shed light on the extent to which chondrichthyan brains have evolved as a consequence of behaviour, habitat and lifestyle in addition to phylogeny.

@article{doi101111j10958649201203254x,
    author = "Yopak, Kara E.",
    title = "Neuroecology of cartilaginous fishes: the functional implications of brain scaling",
    year = "2012",
    journal = "Journal of Fish Biology",
    abstract = "It is a widely accepted view that neural development can reflect morphological adaptations and sensory specializations. The aim of this review is to give a broad overview of the current status of brain data available for cartilaginous fishes and examine how perspectives on allometric scaling of brain size across this group of fishes has changed within the last 50 years with the addition of new data and more rigorous statistical analyses. The current knowledge of neuroanatomy in cartilaginous fishes is reviewed and data on brain size (encephalization, n = 151) and interspecific variation in brain organization (n = 84) has been explored to ascertain scaling relationships across this clade. It is determined whether similar patterns of brain organization, termed cerebrotypes, exist in species that share certain lifestyle characteristics. Clear patterns of brain organization exist across cartilaginous fishes, irrespective of phylogenetic grouping and, although this study was not a functional analysis, it provides further evidence that chondrichthyan brain structures might have developed in conjunction with specific behaviours or enhanced cognitive capabilities. Larger brains, with well-developed telencephala and large, highly foliated cerebella are reported in species that occupy complex reef or oceanic habitats, potentially identifying a reef-associated cerebrotype. In contrast, benthic and benthopelagic demersal species comprise the group with the smallest brains, with a relatively reduced telencephalon and a smooth cerebellar corpus. There is also evidence herein of a bathyal cerebrotype; deep-sea benthopelagic sharks possess relatively small brains and show a clear relative hypertrophy of the medulla oblongata. Despite the patterns observed and documented, significant gaps in the literature have been highlighted. Brain mass data are only currently available on c. 16\% of all chondrichthyan species, and only 8\% of species have data available on their brain organization, with far less on subsections of major brain areas that receive distinct sensory input. The interspecific variability in brain organization further stresses the importance of performing functional studies on a greater range of species. Only an expansive data set, comprised of species that span a variety of habitats and taxonomic groups, with widely disparate behavioural repertoires, combined with further functional analyses, will help shed light on the extent to which chondrichthyan brains have evolved as a consequence of behaviour, habitat and lifestyle in addition to phylogeny.",
    url = "https://doi.org/10.1111/j.1095-8649.2012.03254.x",
    doi = "10.1111/j.1095-8649.2012.03254.x",
    openalex = "W2039393659",
    references = "doi101007978364218262412"
}

Abstract: Fishes include more than half of all living animals with backbones, but large‐scale palaeobiological patterns in this assemblage have not received the same attention as those for terrestrial vertebrates. Previous surveys of the fish record have generally been anecdotal, or limited either in their stratigraphic or in their taxonomic scope. Here, we provide a broad overview of the Phanerozoic history of fish diversity, placing a special emphasis on intervals of turnover, evolutionary radiation, and extinction. In particular, we provide in‐depth reviews of changes during, and ecological and evolutionary recovery after, the end‐Devonian (Hangenberg) and Cretaceous–Palaeogene (K–Pg) extinctions.

@article{doi101111j14754983201201165x,
    author = "Friedman, Matt and Sallan, Lauren",
    title = "Five hundred million years of extinction and recovery: a phanerozoic survey of large‐scale diversity patterns in fishes",
    year = "2012",
    journal = "Palaeontology",
    abstract = "Abstract: Fishes include more than half of all living animals with backbones, but large‐scale palaeobiological patterns in this assemblage have not received the same attention as those for terrestrial vertebrates. Previous surveys of the fish record have generally been anecdotal, or limited either in their stratigraphic or in their taxonomic scope. Here, we provide a broad overview of the Phanerozoic history of fish diversity, placing a special emphasis on intervals of turnover, evolutionary radiation, and extinction. In particular, we provide in‐depth reviews of changes during, and ecological and evolutionary recovery after, the end‐Devonian (Hangenberg) and Cretaceous–Palaeogene (K–Pg) extinctions.",
    url = "https://doi.org/10.1111/j.1475-4983.2012.01165.x",
    doi = "10.1111/j.1475-4983.2012.01165.x",
    openalex = "W1522554964",
    references = "brinkman1990paleooecology, brinkman2002teleost, crossref1977patterns, doi101002gj1072, doi1010079781468464658, doi101016jpalaeo200907017, doi101016jpalaeo200910010, doi101016s0016699588800664, doi101017s0022336000024331, doi101017s0094837300005352, doi101017s0094837300008174, doi101017s1477201908002551, doi101038nature01264, doi101038nature07855, doi101038nature08745, doi101038nature09038, doi101073pnas0811087106, doi101073pnas1010350107, doi101073pnas1117332109, doi10108002724634199710010948, doi101098rspb20011826, doi101098rspb20080715, doi101111j1469185x1999tb00045x, doi101111j14754983201001019x, doi101111j150239311983tb01993x, doi101126science1177265, doi101126science1598573, doi101126science21545391501, doi101146annurevearth040809152556, doi101146annurevecolsys35021103105715, doi1016710272463420010210438anscft20co2, doi1023071441916, doi1023073514548, doi102475ajs2882101, doi104072rbp2005205, doi105252g2010n4a1, doi105860choice435902, doi105962bhltitle4275, openalexw1485830652, openalexw2106559152, openalexw2208603329, openalexw3001739384, openalexw595691412, openalexw606525048"
}

Interest in elasmobranch biodiversity and taxonomy has grown in recent years, catalyzed primarily by four inuences: (1) the large number of new species that have been described over the past 30 years (e.g., Last and Stevens, 2009); (2) the recognition that many species of elasmobranchs, several of which have not yet been formally described, may be threatened with extinction from shing pressures and habitat destruction (Stevens et al., 2000); (3) the growing interest in DNA “barcoding” as a tool to augment taxonomic description (e.g., Ward et al., 2007); and (4) an emerging recognition of the important role that elasmobranchs play as top predators in marine ecosystems (Heithaus et al., 2008).

@incollection{doi101201b118679,
    author = "Naylor, Janine N. Caira Gavin",
    title = "Elasmobranch Phylogeny: A Mitochondrial Estimate Based on 595 Species",
    year = "2012",
    abstract = "Interest in elasmobranch biodiversity and taxonomy has grown in recent years, catalyzed primarily by four inuences: (1) the large number of new species that have been described over the past 30 years (e.g., Last and Stevens, 2009); (2) the recognition that many species of elasmobranchs, several of which have not yet been formally described, may be threatened with extinction from shing pressures and habitat destruction (Stevens et al., 2000); (3) the growing interest in DNA “barcoding” as a tool to augment taxonomic description (e.g., Ward et al., 2007); and (4) an emerging recognition of the important role that elasmobranchs play as top predators in marine ecosystems (Heithaus et al., 2008).",
    url = "https://doi.org/10.1201/b11867-9",
    doi = "10.1201/b11867-9",
    openalex = "W2500401673",
    references = "doi101093icb172303, doi101111j109636421996tb02189x, doi1012060003009020042840001fsotgr20co2, doi1023071447424, openalexw3211386673"
}

ABSTRACT This study presents the first comprehensive revision of ‘pholidophoriform’ fishes, which are a key taxon for understanding the early diversification of teleost fish. Systematic revisions of Triassic pholidophorids, which are based on numerous well-preserved specimens, include †Annaichthys, gen. et sp. nov., †Knerichthys, gen. nov., †Parapholidophorus, †Pholidoctenus, †Pholidophoretes, †Pholidophorus, †Pholidorhynchodon, and †Zambellichthys, gen. et sp. nov. The morphological descriptions presented support a phylogenetic analysis that proposes a new hypothesis for character evolution within basal Teleostei, with implications for holosteans and teleosteans. The phylogenetic analysis resolves traditional ‘pholidophoriform’ species as a paraphyletic assemblage, with some grouped in a monophyletic †Pholidophoridae and others more closely related to crown-group teleosts. The monophyletic Family †Pholidophoridae is restricted to European Triassic taxa and is the sister group of the Jurassic genus †Eurycormus plus all other teleosts. The latter clade is supported by several synapomorphies, such as an elongate posteroventral process of the quadrate, long epineural processes, and seven or more ural neural arches modified as uroneurals. †Pholidophorus bechei is removed from †Pholidophoridae and recognized as the new genus †Dorsetichthys. Current evidence indicates that the Upper Triassic †Pholidophoretes salvus and †Knerichthys bronni represent the oldest known pholidophorids, and †Prohalecites from the Middle/Upper Triassic boundary represents the oldest stem teleost. Aspidorhynchiforms, pachycormiforms, and †Prohalecites are resolved as stem teleosts. The monophyly of Teleostei, which now includes Triassic pholidophorids, is supported by numerous synapomorphies, such as one suborbital, two supramaxillae, and the articular fused to the angular and retroarticular bones—with further transformations within more advanced teleosts. Synapomorphies of Teleosteomorpha, the clade including crown-group teleosts and all fish more closely related to them than to their closest extant relatives, include the autosphenotic lacking a dermal component, an unpaired vomer, and one long, toothed, serrated appendage on the cleithrum.

@article{doi101080027246342013835642,
    author = "Arratia, Gloria",
    title = "Morphology, taxonomy, and phylogeny of Triassic pholidophorid fishes (Actinopterygii, Teleostei)",
    year = "2013",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT This study presents the first comprehensive revision of ‘pholidophoriform’ fishes, which are a key taxon for understanding the early diversification of teleost fish. Systematic revisions of Triassic pholidophorids, which are based on numerous well-preserved specimens, include †Annaichthys, gen. et sp. nov., †Knerichthys, gen. nov., †Parapholidophorus, †Pholidoctenus, †Pholidophoretes, †Pholidophorus, †Pholidorhynchodon, and †Zambellichthys, gen. et sp. nov. The morphological descriptions presented support a phylogenetic analysis that proposes a new hypothesis for character evolution within basal Teleostei, with implications for holosteans and teleosteans. The phylogenetic analysis resolves traditional ‘pholidophoriform’ species as a paraphyletic assemblage, with some grouped in a monophyletic †Pholidophoridae and others more closely related to crown-group teleosts. The monophyletic Family †Pholidophoridae is restricted to European Triassic taxa and is the sister group of the Jurassic genus †Eurycormus plus all other teleosts. The latter clade is supported by several synapomorphies, such as an elongate posteroventral process of the quadrate, long epineural processes, and seven or more ural neural arches modified as uroneurals. †Pholidophorus bechei is removed from †Pholidophoridae and recognized as the new genus †Dorsetichthys. Current evidence indicates that the Upper Triassic †Pholidophoretes salvus and †Knerichthys bronni represent the oldest known pholidophorids, and †Prohalecites from the Middle/Upper Triassic boundary represents the oldest stem teleost. Aspidorhynchiforms, pachycormiforms, and †Prohalecites are resolved as stem teleosts. The monophyly of Teleostei, which now includes Triassic pholidophorids, is supported by numerous synapomorphies, such as one suborbital, two supramaxillae, and the articular fused to the angular and retroarticular bones—with further transformations within more advanced teleosts. Synapomorphies of Teleosteomorpha, the clade including crown-group teleosts and all fish more closely related to them than to their closest extant relatives, include the autosphenotic lacking a dermal component, an unpaired vomer, and one long, toothed, serrated appendage on the cleithrum.",
    url = "https://doi.org/10.1080/02724634.2013.835642",
    doi = "10.1080/02724634.2013.835642",
    openalex = "W2113950930",
    references = "doi10100797814612356063, doi101007978146848851721, doi105962bhltitle6408, openalexw2898156694"
}

Abstract Engelhard, G. H., Peck, M. A., Rindorf, A., Smout, S. C., van Deurs, M., Raab, K., Andersen, K. H., Garthe, S., Lauerburg, R. A. M., Scott, F., Brunel, T., Aarts, G., van Kooten, T., and Dickey-Collas, M. Forage fish, their fisheries, and their predators: who drives whom? – ICES Journal of Marine Science, 71:. The North Sea has a diverse forage fish assemblage, including herring, targeted for human consumption; sandeel, sprat, and Norway pout, exploited by industrial fisheries; and some sardine and anchovy, supporting small-scale fisheries. All show large abundance fluctuations, impacting on fisheries and predators. We review field, laboratory, and modelling studies to investigate the drivers of this complex system of forage fish. Climate clearly influences forage fish productivity; however, any single-species considerations of the influence of climate might fail if strong interactions between forage fish exist, as in the North Sea. Sandeel appears to be the most important prey forage fish. Seabirds are most dependent on forage fish, due to specialized diet and distributional constraints (breeding colonies). Other than fisheries, key predators of forage fish are a few piscivorous fish species including saithe, whiting, mackerel, and horse-mackerel, exploited in turn by fisheries; seabirds and seals have a more modest impact. Size-based foodweb modelling suggests that reducing fishing mortality may not necessarily lead to larger stocks of piscivorous fish, especially if their early life stages compete with forage fish for zooplankton resources. In complex systems, changes in the impact of fisheries on forage fish may have potentially complex (and perhaps unanticipated) consequences on other commercially and/or ecologically important species.

@article{doi101093icesjmsfst087,
    author = "Engelhard, Georg H. and Peck, Myron A. and Rindorf, Anna and Smout, Sophie and van Deurs, Mikael and Raab, Kristina and Andersen, Ken H. and Garthe, Stefan and Lauerburg, Rebecca A.M. and Finlay, Scott and Brunel, Thomas and Aarts, Geert and van Kooten, Tobias and Dickey‐Collas, Mark",
    title = "Forage fish, their fisheries, and their predators: who drives whom?",
    year = "2013",
    journal = "ICES Journal of Marine Science",
    abstract = "Abstract Engelhard, G. H., Peck, M. A., Rindorf, A., Smout, S. C., van Deurs, M., Raab, K., Andersen, K. H., Garthe, S., Lauerburg, R. A. M., Scott, F., Brunel, T., Aarts, G., van Kooten, T., and Dickey-Collas, M. Forage fish, their fisheries, and their predators: who drives whom? – ICES Journal of Marine Science, 71:. The North Sea has a diverse forage fish assemblage, including herring, targeted for human consumption; sandeel, sprat, and Norway pout, exploited by industrial fisheries; and some sardine and anchovy, supporting small-scale fisheries. All show large abundance fluctuations, impacting on fisheries and predators. We review field, laboratory, and modelling studies to investigate the drivers of this complex system of forage fish. Climate clearly influences forage fish productivity; however, any single-species considerations of the influence of climate might fail if strong interactions between forage fish exist, as in the North Sea. Sandeel appears to be the most important prey forage fish. Seabirds are most dependent on forage fish, due to specialized diet and distributional constraints (breeding colonies). Other than fisheries, key predators of forage fish are a few piscivorous fish species including saithe, whiting, mackerel, and horse-mackerel, exploited in turn by fisheries; seabirds and seals have a more modest impact. Size-based foodweb modelling suggests that reducing fishing mortality may not necessarily lead to larger stocks of piscivorous fish, especially if their early life stages compete with forage fish for zooplankton resources. In complex systems, changes in the impact of fisheries on forage fish may have potentially complex (and perhaps unanticipated) consequences on other commercially and/or ecologically important species.",
    url = "https://doi.org/10.1093/icesjms/fst087",
    doi = "10.1093/icesjms/fst087",
    openalex = "W2136507145",
    references = "doi101007bf00042661"
}

Development of uterine glands (adenogenesis) in mammals typically begins during the early post-natal period and involves budding of nascent glands from the luminal epithelium and extensive cell proliferation in these structures as they grow into the surrounding stroma, elongate and mature. Uterine glands are essential for pregnancy, as demonstrated by the infertility that results from inhibiting the development of these glands through gene mutation or epigenetic strategies. Several genes, including forkhead box A2, beta-catenin and members of the Wnt and Hox gene families, are implicated in uterine gland development. Progestins inhibit uterine epithelial proliferation, and this has been employed as a strategy to develop a model in which progestin treatment of ewes for 8 weeks from birth produces infertile adults lacking uterine glands. More recently, mouse models have been developed in which neonatal progestin treatment was used to permanently inhibit adenogenesis and adult fertility. These studies revealed a narrow and well-defined window in which progestin treatments induced permanent infertility by impairing neonatal gland development and establishing endometrial changes that result in implantation defects. These model systems are being utilized to better understand the molecular mechanisms underlying uterine adenogenesis and endometrial function. The ability of neonatal progestin treatment in sheep and mice to produce infertility suggests that an approach of this kind may provide a contraceptive strategy with application in other species. Recent studies have defined the temporal patterns of adenogenesis in uteri of neonatal and juvenile dogs and work is underway to determine whether neonatal progestin or other steroid hormone treatments might be a viable contraceptive approach in this species.

@article{doi101093molehrgat031,
    author = "Cooke, Paul S. and Spencer, Thomas E. and Bartol, Frank F. and Hayashi, Kanako",
    title = "Uterine glands: development, function and experimental model systems",
    year = "2013",
    journal = "Molecular Human Reproduction",
    abstract = "Development of uterine glands (adenogenesis) in mammals typically begins during the early post-natal period and involves budding of nascent glands from the luminal epithelium and extensive cell proliferation in these structures as they grow into the surrounding stroma, elongate and mature. Uterine glands are essential for pregnancy, as demonstrated by the infertility that results from inhibiting the development of these glands through gene mutation or epigenetic strategies. Several genes, including forkhead box A2, beta-catenin and members of the Wnt and Hox gene families, are implicated in uterine gland development. Progestins inhibit uterine epithelial proliferation, and this has been employed as a strategy to develop a model in which progestin treatment of ewes for 8 weeks from birth produces infertile adults lacking uterine glands. More recently, mouse models have been developed in which neonatal progestin treatment was used to permanently inhibit adenogenesis and adult fertility. These studies revealed a narrow and well-defined window in which progestin treatments induced permanent infertility by impairing neonatal gland development and establishing endometrial changes that result in implantation defects. These model systems are being utilized to better understand the molecular mechanisms underlying uterine adenogenesis and endometrial function. The ability of neonatal progestin treatment in sheep and mice to produce infertility suggests that an approach of this kind may provide a contraceptive strategy with application in other species. Recent studies have defined the temporal patterns of adenogenesis in uteri of neonatal and juvenile dogs and work is underway to determine whether neonatal progestin or other steroid hormone treatments might be a viable contraceptive approach in this species.",
    url = "https://doi.org/10.1093/molehr/gat031",
    doi = "10.1093/molehr/gat031",
    openalex = "W2098274784",
    references = "doi105694j132653771943tb44800x"
}

With the flood of published research encountered today, it is important to occasionally reflect upon how we arrived at our current understanding in a particular scientific discipline, thereby positioning new discoveries into proper context with long-established models. This historical review highlights some of the important scientific contributions in the field of neurogenic placode development. By viewing cumulatively the rich historical data, we can more fully appreciate and apply what has been accomplished. Early descriptive work in fish and experimental approaches in amphibians and chick yielded important conceptual models of placode induction and cellular differentiation. Current efforts to discover genes and their molecular functions continue to expand our understanding of the placodes. Carefully considering the body of work may improve current models and help focus modern experimental design.

@article{doi101002dvdy24152,
    author = "Stark, Michael R.",
    title = "Vertebrate neurogenic placode development: Historical highlights that have shaped our current understanding",
    year = "2014",
    journal = "Developmental Dynamics",
    abstract = "With the flood of published research encountered today, it is important to occasionally reflect upon how we arrived at our current understanding in a particular scientific discipline, thereby positioning new discoveries into proper context with long-established models. This historical review highlights some of the important scientific contributions in the field of neurogenic placode development. By viewing cumulatively the rich historical data, we can more fully appreciate and apply what has been accomplished. Early descriptive work in fish and experimental approaches in amphibians and chick yielded important conceptual models of placode induction and cellular differentiation. Current efforts to discover genes and their molecular functions continue to expand our understanding of the placodes. Carefully considering the body of work may improve current models and help focus modern experimental design.",
    url = "https://doi.org/10.1002/dvdy.24152",
    doi = "10.1002/dvdy.24152",
    openalex = "W1552342615",
    references = "doi101242jcss229114153"
}

Morphological comparisons among extant animals have long been used to infer their long-extinct ancestors for which the fossil record is poor or non-existent. For evolution of the vertebrates, the comparison has typically involved amphioxus and vertebrates. Both groups are evolving relatively slowly, and their genomes share a high level of synteny. Both vertebrates and amphioxus have regulative development in which cell fates become fixed only gradually during embryogenesis. Thus, their development fits a modified hourglass model in which constraints are greatest at the phylotypic stage (i.e., the late neurula/early larva), but are somewhat greater on earlier development than on later development. In contrast, the third group of chordates, the tunicates, which are sister group to vertebrates, are evolving rapidly. Constraints on evolution of tunicate genomes are relaxed, and they have discarded key developmental genes and organized much of their coding sequences into operons, which are transcribed as a single mRNA that undergoes trans-splicing. This contrasts with vertebrates and amphioxus, whose genomes are not organized into operons. Concomitantly, tunicates have switched to determinant development with very early fixation of cell fates. Thus, tunicate development more closely fits a progressive divergence model (shaped more like a wine glass than an hourglass) in which the constraints on the zygote and very early development are greatest. This model can help explain why tunicate body plans are so very diverse. The relaxed constraints on development after early cleavage stages are correlated with relaxed constraints on genome evolution. The question remains: which came first?

@article{doi101002jezb22569,
    author = "Holland, Linda Z.",
    title = "Genomics, evolution and development of amphioxus and tunicates: The Goldilocks principle",
    year = "2014",
    journal = "Journal of Experimental Zoology Part B Molecular and Developmental Evolution",
    abstract = "Morphological comparisons among extant animals have long been used to infer their long-extinct ancestors for which the fossil record is poor or non-existent. For evolution of the vertebrates, the comparison has typically involved amphioxus and vertebrates. Both groups are evolving relatively slowly, and their genomes share a high level of synteny. Both vertebrates and amphioxus have regulative development in which cell fates become fixed only gradually during embryogenesis. Thus, their development fits a modified hourglass model in which constraints are greatest at the phylotypic stage (i.e., the late neurula/early larva), but are somewhat greater on earlier development than on later development. In contrast, the third group of chordates, the tunicates, which are sister group to vertebrates, are evolving rapidly. Constraints on evolution of tunicate genomes are relaxed, and they have discarded key developmental genes and organized much of their coding sequences into operons, which are transcribed as a single mRNA that undergoes trans-splicing. This contrasts with vertebrates and amphioxus, whose genomes are not organized into operons. Concomitantly, tunicates have switched to determinant development with very early fixation of cell fates. Thus, tunicate development more closely fits a progressive divergence model (shaped more like a wine glass than an hourglass) in which the constraints on the zygote and very early development are greatest. This model can help explain why tunicate body plans are so very diverse. The relaxed constraints on development after early cleavage stages are correlated with relaxed constraints on genome evolution. The question remains: which came first?",
    url = "https://doi.org/10.1002/jez.b.22569",
    doi = "10.1002/jez.b.22569",
    openalex = "W1560143667",
    references = "doi101186147121487127, doi101186147122021359, doi105962bhltitle55924, zhou2012systematic"
}

The zebrafish lateral line is a sensory system used to detect changes in water flow. It is comprised of clusters of mechanosensory hair cells called neuromasts. The lateral line is initially established by a migratory group of cells, called a primordium, that deposits neuromasts at stereotyped locations along the surface of the fish. Wnt, FGF, and Notch signaling are all important regulators of various aspects of lateral line development, from primordium migration to hair cell specification. As zebrafish age, the organization of the lateral line becomes more complex in order to accommodate the fish's increased size. This expansion is regulated by many of the same factors involved in the initial development. Furthermore, unlike mammalian hair cells, lateral line hair cells have the capacity to regenerate after damage. New hair cells arise from the proliferation and differentiation of surrounding support cells, and the molecular and cellular pathways regulating this are beginning to be elucidated. All in all, the zebrafish lateral line has proven to be an excellent model in which to study a diverse array of processes, including collective cell migration, cell polarity, cell fate, and regeneration.

@article{doi101002wdev160,
    author = "Thomas, Eric D. and Cruz, Ivan and Hailey, Dale W. and Raible, David W.",
    title = "There and back again: development and regeneration of the zebrafish lateral line system",
    year = "2014",
    journal = "Wiley Interdisciplinary Reviews Developmental Biology",
    abstract = "The zebrafish lateral line is a sensory system used to detect changes in water flow. It is comprised of clusters of mechanosensory hair cells called neuromasts. The lateral line is initially established by a migratory group of cells, called a primordium, that deposits neuromasts at stereotyped locations along the surface of the fish. Wnt, FGF, and Notch signaling are all important regulators of various aspects of lateral line development, from primordium migration to hair cell specification. As zebrafish age, the organization of the lateral line becomes more complex in order to accommodate the fish's increased size. This expansion is regulated by many of the same factors involved in the initial development. Furthermore, unlike mammalian hair cells, lateral line hair cells have the capacity to regenerate after damage. New hair cells arise from the proliferation and differentiation of surrounding support cells, and the molecular and cellular pathways regulating this are beginning to be elucidated. All in all, the zebrafish lateral line has proven to be an excellent model in which to study a diverse array of processes, including collective cell migration, cell polarity, cell fate, and regeneration.",
    url = "https://doi.org/10.1002/wdev.160",
    doi = "10.1002/wdev.160",
    openalex = "W1999024564",
    references = "doi101016jydbio201402016"
}

The Permian and Triassic were key time intervals in the history of life on Earth. Both periods are marked by a series of biotic crises including the most catastrophic of such events, the end-Permian mass extinction, which eventually led to a major turnover from typical Palaeozoic faunas and floras to those that are emblematic for the Mesozoic and Cenozoic. Here we review patterns in Permian-Triassic bony fishes, a group whose evolutionary dynamics are understudied. Based on data from primary literature, we analyse changes in their taxonomic diversity and body size (as a proxy for trophic position) and explore their response to Permian-Triassic events. Diversity and body size are investigated separately for different groups of Osteichthyes (Dipnoi, Actinistia, 'Palaeopterygii', 'Subholostei', Holostei, Teleosteomorpha), within the marine and freshwater realms and on a global scale (total diversity) as well as across palaeolatitudinal belts. Diversity is also measured for different palaeogeographical provinces. Our results suggest a general trend from low osteichthyan diversity in the Permian to higher levels in the Triassic. Diversity dynamics in the Permian are marked by a decline in freshwater taxa during the Cisuralian. An extinction event during the end-Guadalupian crisis is not evident from our data, but 'palaeopterygians' experienced a significant body size increase across the Guadalupian-Lopingian boundary and these fishes upheld their position as large, top predators from the Late Permian to the Late Triassic. Elevated turnover rates are documented at the Permian-Triassic boundary, and two distinct diversification events are noted in the wake of this biotic crisis, a first one during the Early Triassic (dipnoans, actinistians, 'palaeopterygians', 'subholosteans') and a second one during the Middle Triassic ('subholosteans', neopterygians). The origination of new, small taxa predominantly among these groups during the Middle Triassic event caused a significant reduction in osteichthyan body size. Neopterygii, the clade that encompasses the vast majority of extant fishes, underwent another diversification phase in the Late Triassic. The Triassic radiation of Osteichthyes, predominantly of Actinopterygii, which only occurred after severe extinctions among Chondrichthyes during the Middle-Late Permian, resulted in a profound change within global fish communities, from chondrichthyan-rich faunas of the Permo-Carboniferous to typical Mesozoic and Cenozoic associations dominated by actinopterygians. This turnover was not sudden but followed a stepwise pattern, with leaps during extinction events.

@article{doi101111brv12161,
    author = "Romano, Carlo and Koot, Martha B. and Kogan, Ilja and Brayard, Arnaud and Minikh, Alla V. and Brinkmann, Winand and Bucher, Hugo and Kriwet, Jürgen",
    title = "Permian– T riassic O steichthyes (bony fishes): diversity dynamics and body size evolution",
    year = "2014",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "The Permian and Triassic were key time intervals in the history of life on Earth. Both periods are marked by a series of biotic crises including the most catastrophic of such events, the end-Permian mass extinction, which eventually led to a major turnover from typical Palaeozoic faunas and floras to those that are emblematic for the Mesozoic and Cenozoic. Here we review patterns in Permian-Triassic bony fishes, a group whose evolutionary dynamics are understudied. Based on data from primary literature, we analyse changes in their taxonomic diversity and body size (as a proxy for trophic position) and explore their response to Permian-Triassic events. Diversity and body size are investigated separately for different groups of Osteichthyes (Dipnoi, Actinistia, 'Palaeopterygii', 'Subholostei', Holostei, Teleosteomorpha), within the marine and freshwater realms and on a global scale (total diversity) as well as across palaeolatitudinal belts. Diversity is also measured for different palaeogeographical provinces. Our results suggest a general trend from low osteichthyan diversity in the Permian to higher levels in the Triassic. Diversity dynamics in the Permian are marked by a decline in freshwater taxa during the Cisuralian. An extinction event during the end-Guadalupian crisis is not evident from our data, but 'palaeopterygians' experienced a significant body size increase across the Guadalupian-Lopingian boundary and these fishes upheld their position as large, top predators from the Late Permian to the Late Triassic. Elevated turnover rates are documented at the Permian-Triassic boundary, and two distinct diversification events are noted in the wake of this biotic crisis, a first one during the Early Triassic (dipnoans, actinistians, 'palaeopterygians', 'subholosteans') and a second one during the Middle Triassic ('subholosteans', neopterygians). The origination of new, small taxa predominantly among these groups during the Middle Triassic event caused a significant reduction in osteichthyan body size. Neopterygii, the clade that encompasses the vast majority of extant fishes, underwent another diversification phase in the Late Triassic. The Triassic radiation of Osteichthyes, predominantly of Actinopterygii, which only occurred after severe extinctions among Chondrichthyes during the Middle-Late Permian, resulted in a profound change within global fish communities, from chondrichthyan-rich faunas of the Permo-Carboniferous to typical Mesozoic and Cenozoic associations dominated by actinopterygians. This turnover was not sudden but followed a stepwise pattern, with leaps during extinction events.",
    url = "https://doi.org/10.1111/brv.12161",
    doi = "10.1111/brv.12161",
    openalex = "W1940825182",
    references = "doi101002bies201200145, doi101002jmor20272, doi101016jearscirev201305014, doi101016jgr201212010, doi101046j14672979200000015x, doi101073pnas1206625109, doi101093jpertr044, doi101093oso97801985404720010001, doi101126science1097023, doi101126science1157719, doi101126science1213454, doi101126science1224126, doi101371currentstol53ba26640df0ccaee75bb165c8c26288, doi101371journalpone0088987, doi1018901119521, doi102475ajs28211, doi105252g2010n4a1, doi105962bhltitle159141, doi105962p313860, doi107146moggeosciv32i140904, openalexw2183707334, openalexw2898156694, openalexw628087051, schultze1986wirbeltierreste"
}

Axonal connections between the left and right sides of the brain are crucial for bilateral integration of lateralized sensory, motor, and associative functions. Throughout vertebrate species, forebrain commissures share a conserved developmental plan, a similar position relative to each other within the brain and similar patterns of connectivity. However, major events in the evolution of the vertebrate brain, such as the expansion of the telencephalon in tetrapods and the origin of the six-layered isocortex in mammals, resulted in the emergence and diversification of new commissural routes. These new interhemispheric connections include the pallial commissure, which appeared in the ancestors of tetrapods and connects the left and right sides of the medial pallium (hippocampus in mammals), and the corpus callosum, which is exclusive to eutherian (placental) mammals and connects both isocortical hemispheres. A comparative analysis of commissural systems in vertebrates reveals that the emergence of new commissural routes may have involved co-option of developmental mechanisms and anatomical substrates of preexistent commissural pathways. One of the embryonic regions of interest for studying these processes is the commissural plate, a portion of the early telencephalic midline that provides molecular specification and a cellular scaffold for the development of commissural axons. Further investigations into these embryonic processes in carefully selected species will provide insights not only into the mechanisms driving commissural evolution, but also regarding more general biological problems such as the role of developmental plasticity in evolutionary change.

@article{doi103389fnhum201400497,
    author = "Suárez, Rodrigo and Gobius, Ilan and Richards, Linda J.",
    title = "Evolution and development of interhemispheric connections in the vertebrate forebrain",
    year = "2014",
    journal = "Frontiers in Human Neuroscience",
    abstract = "Axonal connections between the left and right sides of the brain are crucial for bilateral integration of lateralized sensory, motor, and associative functions. Throughout vertebrate species, forebrain commissures share a conserved developmental plan, a similar position relative to each other within the brain and similar patterns of connectivity. However, major events in the evolution of the vertebrate brain, such as the expansion of the telencephalon in tetrapods and the origin of the six-layered isocortex in mammals, resulted in the emergence and diversification of new commissural routes. These new interhemispheric connections include the pallial commissure, which appeared in the ancestors of tetrapods and connects the left and right sides of the medial pallium (hippocampus in mammals), and the corpus callosum, which is exclusive to eutherian (placental) mammals and connects both isocortical hemispheres. A comparative analysis of commissural systems in vertebrates reveals that the emergence of new commissural routes may have involved co-option of developmental mechanisms and anatomical substrates of preexistent commissural pathways. One of the embryonic regions of interest for studying these processes is the commissural plate, a portion of the early telencephalic midline that provides molecular specification and a cellular scaffold for the development of commissural axons. Further investigations into these embryonic processes in carefully selected species will provide insights not only into the mechanisms driving commissural evolution, but also regarding more general biological problems such as the role of developmental plasticity in evolutionary change.",
    url = "https://doi.org/10.3389/fnhum.2014.00497",
    doi = "10.3389/fnhum.2014.00497",
    openalex = "W2003046304",
    references = "doi101007978364218262412"
}

The evolutionary origin of the vertebrate jaw persists as a deeply puzzling mystery. More than 99% of living vertebrates have jaws, but the evolutionary sequence that ultimately gave rise to this highly successful innovation remains controversial. A synthesis of recent fossil and embryological findings offers a novel solution to this enduring puzzle. The Mandibular Confinement Hypothesis proposes that the jaw evolved via spatial confinement of the mandibular arch (the most anterior pharyngeal arch within which the jaw arose). Fossil and anatomical evidence reveals: (i) the mandibular region was initially extensive and distinct among the pharyngeal arches; and (ii) with spatial confinement, the mandibular arch acquired a common pharyngeal pattern only at the origin of the jaw. The confinement occurred via a shift of a domain boundary that restricted the space the mesenchymal cells of the mandibular arch could occupy. As the surrounding domains replaced mandibular structures at the periphery, this shift allowed neural crest cells and mesodermal mesenchyme of the mandibular arch to acquire patterning programs that operate in the more posterior arches. The mesenchymal population within the mandibular arch was therefore no longer required to differentiate into specialized feeding and ventilation structures, and was remodelled into a jaw. Embryological evidence corroborates that the mandibular arch must be spatially confined for a jaw to develop. This new interpretation suggests neural crest as a key facilitator in correlating elements of the classically recognized vertebrate head 'segmentation'.

@article{doi101111brv12187,
    author = "Miyashita, Tetsuto",
    title = "Fishing for jaws in early vertebrate evolution: a new hypothesis of mandibular confinement",
    year = "2015",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "The evolutionary origin of the vertebrate jaw persists as a deeply puzzling mystery. More than 99\% of living vertebrates have jaws, but the evolutionary sequence that ultimately gave rise to this highly successful innovation remains controversial. A synthesis of recent fossil and embryological findings offers a novel solution to this enduring puzzle. The Mandibular Confinement Hypothesis proposes that the jaw evolved via spatial confinement of the mandibular arch (the most anterior pharyngeal arch within which the jaw arose). Fossil and anatomical evidence reveals: (i) the mandibular region was initially extensive and distinct among the pharyngeal arches; and (ii) with spatial confinement, the mandibular arch acquired a common pharyngeal pattern only at the origin of the jaw. The confinement occurred via a shift of a domain boundary that restricted the space the mesenchymal cells of the mandibular arch could occupy. As the surrounding domains replaced mandibular structures at the periphery, this shift allowed neural crest cells and mesodermal mesenchyme of the mandibular arch to acquire patterning programs that operate in the more posterior arches. The mesenchymal population within the mandibular arch was therefore no longer required to differentiate into specialized feeding and ventilation structures, and was remodelled into a jaw. Embryological evidence corroborates that the mandibular arch must be spatially confined for a jaw to develop. This new interpretation suggests neural crest as a key facilitator in correlating elements of the classically recognized vertebrate head 'segmentation'.",
    url = "https://doi.org/10.1111/brv.12187",
    doi = "10.1111/brv.12187",
    openalex = "W1548546189",
    references = "doi101016jydbio201108003, doi101016jydbio201302022, doi101093icb12177, doi101111j146364091974tb00816x, doi101111j146364091978tb00792x, doi101111zoj12111, doi101111zoj12186"
}

We demonstrate that Nodal signaling is necessary for establishing the LR embryonic axis and for developing profound asymmetry in amphioxus. Our data suggest that initial symmetry breaking in amphioxus and propagation of the pathway on the left side correspond with the situation in vertebrates. However, the organs that become targets of the pathway differ between amphioxus and vertebrates, which may explain the pronounced asymmetry of its oropharyngeal and axial structures and the left-sided position of the mouth.

@article{doi1011862041913965,
    author = "Soukup, Vladimír and Yong, Luok Wen and Lu, Tsai-Ming and Huang, Song-Wei and Kozmík, Zbyněk and Yu, Jr‐Kai",
    title = "The Nodal signaling pathway controls left-right asymmetric development in amphioxus",
    year = "2015",
    journal = "EvoDevo",
    abstract = "We demonstrate that Nodal signaling is necessary for establishing the LR embryonic axis and for developing profound asymmetry in amphioxus. Our data suggest that initial symmetry breaking in amphioxus and propagation of the pathway on the left side correspond with the situation in vertebrates. However, the organs that become targets of the pathway differ between amphioxus and vertebrates, which may explain the pronounced asymmetry of its oropharyngeal and axial structures and the left-sided position of the mouth.",
    url = "https://doi.org/10.1186/2041-9139-6-5",
    doi = "10.1186/2041-9139-6-5",
    openalex = "W2147537972",
    references = "doi101002dvdy20401, doi101006dbio20009630, doi101007s004270050309, doi101016jydbio201005016, doi101016jydbio201102014, doi101016jydbio201108003, doi101242dev073833, doi105962bhltitle55924"
}

Two major skeletal systems-the endoskeleton and exoskeleton-are recognized in vertebrate evolution. Here, we propose that these two systems are distinguished primarily by their relative positions, not by differences in embryonic histogenesis or cell lineage of origin. Comparative embryologic analyses have shown that both types of skeleton have changed their mode of histogenesis during evolution. Although exoskeletons were thought to arise exclusively from the neural crest, recent experiments in teleosts have shown that exoskeletons in the trunk are mesodermal in origin. The enameloid and dentine-coated postcranial exoskeleton seen in many vertebrates does not appear to represent an ancestral condition, as previously hypothesized, but rather a derived condition, in which the enameloid and dentine tissues became accreted to bones. Recent data from placoderm fossils are compatible with this scenario. In contrast, the skull contains neural crest-derived bones in its rostral part. Recent developmental studies suggest that the boundary between neural crest- and mesoderm-derived bones may not be consistent throughout evolution. Rather, the relative positions of bony elements may be conserved, and homologies of bony elements have been retained, with opportunistic changes in the mechanisms and cell lineages of development.

@article{doi101186s4085101400077,
    author = "Hirasawa, Tatsuya and Kuratani, Shigeru",
    title = "Evolution of the vertebrate skeleton: morphology, embryology, and development",
    year = "2015",
    journal = "Zoological Letters",
    abstract = "Two major skeletal systems-the endoskeleton and exoskeleton-are recognized in vertebrate evolution. Here, we propose that these two systems are distinguished primarily by their relative positions, not by differences in embryonic histogenesis or cell lineage of origin. Comparative embryologic analyses have shown that both types of skeleton have changed their mode of histogenesis during evolution. Although exoskeletons were thought to arise exclusively from the neural crest, recent experiments in teleosts have shown that exoskeletons in the trunk are mesodermal in origin. The enameloid and dentine-coated postcranial exoskeleton seen in many vertebrates does not appear to represent an ancestral condition, as previously hypothesized, but rather a derived condition, in which the enameloid and dentine tissues became accreted to bones. Recent data from placoderm fossils are compatible with this scenario. In contrast, the skull contains neural crest-derived bones in its rostral part. Recent developmental studies suggest that the boundary between neural crest- and mesoderm-derived bones may not be consistent throughout evolution. Rather, the relative positions of bony elements may be conserved, and homologies of bony elements have been retained, with opportunistic changes in the mechanisms and cell lineages of development.",
    url = "https://doi.org/10.1186/s40851-014-0007-7",
    doi = "10.1186/s40851-014-0007-7",
    openalex = "W2102956717",
    references = "doi10100703064746897, doi101016jdevcel201007010, doi101017cbo9780511897948, doi101038142004a0, doi101093aesa383396, doi101098rspb19790086, doi101242dev1172409, doi101242dev12781671, doi101671a11168, doi105962bhltitle82144, openalexw1964182146"
}

The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over ~450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary, developmental, and regenerative biological questions that are impossible to explore in classical models.

@article{doi101016jydbio201601038,
    author = "Rasch, Liam J. and Martin, Kyle J. and Cooper, Rory L. and Metscher, Brian and Underwood, Charlie J. and Fraser, Gareth J.",
    title = "An ancient dental gene set governs development and continuous regeneration of teeth in sharks",
    year = "2016",
    journal = "Developmental Biology",
    abstract = "The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over \textasciitilde 450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary, developmental, and regenerative biological questions that are impossible to explore in classical models.",
    url = "https://doi.org/10.1016/j.ydbio.2016.01.038",
    doi = "10.1016/j.ydbio.2016.01.038",
    openalex = "W2268493813",
    references = "doi101002bies200900151, doi101002jmor1051660303, doi101038nature14065, doi101038nature14438"
}

Climate change and decadal variability are impacting marine fish and invertebrate species worldwide and these impacts will continue for the foreseeable future. Quantitative approaches have been developed to examine climate impacts on productivity, abundance, and distribution of various marine fish and invertebrate species. However, it is difficult to apply these approaches to large numbers of species owing to the lack of mechanistic understanding sufficient for quantitative analyses, as well as the lack of scientific infrastructure to support these more detailed studies. Vulnerability assessments provide a framework for evaluating climate impacts over a broad range of species with existing information. These methods combine the exposure of a species to a stressor (climate change and decadal variability) and the sensitivity of species to the stressor. These two components are then combined to estimate an overall vulnerability. Quantitative data are used when available, but qualitative information and expert opinion are used when quantitative data is lacking. Here we conduct a climate vulnerability assessment on 82 fish and invertebrate species in the Northeast U.S. Shelf including exploited, forage, and protected species. We define climate vulnerability as the extent to which abundance or productivity of a species in the region could be impacted by climate change and decadal variability. We find that the overall climate vulnerability is high to very high for approximately half the species assessed; diadromous and benthic invertebrate species exhibit the greatest vulnerability. In addition, the majority of species included in the assessment have a high potential for a change in distribution in response to projected changes in climate. Negative effects of climate change are expected for approximately half of the species assessed, but some species are expected to be positively affected (e.g., increase in productivity or move into the region). These results will inform research and management activities related to understanding and adapting marine fisheries management and conservation to climate change and decadal variability.

@article{doi101371journalpone0146756,
    author = "Hare, Jonathan A. and Morrison, Wendy E. and Nelson, Mark and Stachura, Megan M. and Teeters, Eric J. and Griffis, Roger B. and Alexander, Michael A. and Scott, James D. and Alade, Larry and Bell, Richard J. and Chute, Antonie S. and Curti, Kiersten L. and Curtis, Tobey H. and Kircheis, Daniel and Kocik, John F. and Lucey, Seán and McCandless, Camilla T. and Milke, Lisa M. and Richardson, David E. and Robillard, Eric and Walsh, Harvey J. and McManus, M. Conor and Marancik, Katrin E. and Griswold, Carolyn A.",
    title = "A Vulnerability Assessment of Fish and Invertebrates to Climate Change on the Northeast U.S. Continental Shelf",
    year = "2016",
    journal = "PLoS ONE",
    abstract = "Climate change and decadal variability are impacting marine fish and invertebrate species worldwide and these impacts will continue for the foreseeable future. Quantitative approaches have been developed to examine climate impacts on productivity, abundance, and distribution of various marine fish and invertebrate species. However, it is difficult to apply these approaches to large numbers of species owing to the lack of mechanistic understanding sufficient for quantitative analyses, as well as the lack of scientific infrastructure to support these more detailed studies. Vulnerability assessments provide a framework for evaluating climate impacts over a broad range of species with existing information. These methods combine the exposure of a species to a stressor (climate change and decadal variability) and the sensitivity of species to the stressor. These two components are then combined to estimate an overall vulnerability. Quantitative data are used when available, but qualitative information and expert opinion are used when quantitative data is lacking. Here we conduct a climate vulnerability assessment on 82 fish and invertebrate species in the Northeast U.S. Shelf including exploited, forage, and protected species. We define climate vulnerability as the extent to which abundance or productivity of a species in the region could be impacted by climate change and decadal variability. We find that the overall climate vulnerability is high to very high for approximately half the species assessed; diadromous and benthic invertebrate species exhibit the greatest vulnerability. In addition, the majority of species included in the assessment have a high potential for a change in distribution in response to projected changes in climate. Negative effects of climate change are expected for approximately half of the species assessed, but some species are expected to be positively affected (e.g., increase in productivity or move into the region). These results will inform research and management activities related to understanding and adapting marine fisheries management and conservation to climate change and decadal variability.",
    url = "https://doi.org/10.1371/journal.pone.0146756",
    doi = "10.1371/journal.pone.0146756",
    openalex = "W2256116549",
    references = "doi101111j13652486200902128x"
}

The sensation of touch is mediated by mechanosensory neurons that are embedded in skin and relay signals from the periphery to the central nervous system. During embryogenesis, axons elongate from these neurons to make contact with the developing skin. Concurrently, the epithelium of skin transforms from a homogeneous tissue into a heterogeneous organ that is made up of distinct layers and microdomains. Throughout this process, each neuronal terminal must form connections with an appropriate skin region to serve its function. This Review presents current knowledge of the development of the sensory microdomains in mammalian skin and the mechanosensory neurons that innervate them.

@article{doi101242dev120402,
    author = "Jenkins, Blair A. and Lumpkin, Ellen A.",
    title = "Developing a sense of touch",
    year = "2017",
    journal = "Development",
    abstract = "The sensation of touch is mediated by mechanosensory neurons that are embedded in skin and relay signals from the periphery to the central nervous system. During embryogenesis, axons elongate from these neurons to make contact with the developing skin. Concurrently, the epithelium of skin transforms from a homogeneous tissue into a heterogeneous organ that is made up of distinct layers and microdomains. Throughout this process, each neuronal terminal must form connections with an appropriate skin region to serve its function. This Review presents current knowledge of the development of the sensory microdomains in mammalian skin and the mechanosensory neurons that innervate them.",
    url = "https://doi.org/10.1242/dev.120402",
    doi = "10.1242/dev.120402",
    openalex = "W2769136057",
    references = "doi101016jydbio201402016"
}

INTRODUCTION: The eleventh cranial nerve, the accessory nerve, has a complex and unique anatomy and has been the subject of much debate. Herein, we review the morphology, embryology, surgical anatomy, and clinical manifestations of the accessory nerve. Included in this review, we mention variant anatomy, molecular development, histology, and imaging of the accessory nerve. CONCLUSIONS: The accessory nerve continues to be a topic of much discussion regarding its exact function and in particular to its cranial roots. Recently, various surgical procedures have been devised that repurpose the accessory nerve (e.g., lengthening procedures, contralateral neurotization procedures). Currently, we continue to learn and have much to learn about this lower cranial nerve. Anat Rec, 302:620-629, 2019. © 2018 Wiley Periodicals, Inc.

@article{doi101002ar23823,
    author = "Johal, Jaspreet and Iwanaga, Joe and Tubbs, Kevin and Loukas, Marios and Oskouian, Rod J. and Tubbs, R. Shane",
    title = "The Accessory Nerve: A Comprehensive Review of its Anatomy, Development, Variations, Landmarks and Clinical Considerations",
    year = "2018",
    journal = "The Anatomical Record",
    abstract = "INTRODUCTION: The eleventh cranial nerve, the accessory nerve, has a complex and unique anatomy and has been the subject of much debate. Herein, we review the morphology, embryology, surgical anatomy, and clinical manifestations of the accessory nerve. Included in this review, we mention variant anatomy, molecular development, histology, and imaging of the accessory nerve. CONCLUSIONS: The accessory nerve continues to be a topic of much discussion regarding its exact function and in particular to its cranial roots. Recently, various surgical procedures have been devised that repurpose the accessory nerve (e.g., lengthening procedures, contralateral neurotization procedures). Currently, we continue to learn and have much to learn about this lower cranial nerve. Anat Rec, 302:620-629, 2019. © 2018 Wiley Periodicals, Inc.",
    url = "https://doi.org/10.1002/ar.23823",
    doi = "10.1002/ar.23823",
    openalex = "W2801886639",
    references = "doi101002aja1000040106"
}

Modern cartilaginous fishes are divided into elasmobranchs (sharks, rays and skates) and chimaeras, and the lack of established whole-genome sequences for the former has prevented our understanding of early vertebrate evolution and the unique phenotypes of elasmobranchs. Here we present de novo whole-genome assemblies of brownbanded bamboo shark and cloudy catshark and an improved assembly of the whale shark genome. These relatively large genomes (3.8-6.7 Gbp) contain sparse distributions of coding genes and regulatory elements and exhibit reduced molecular evolutionary rates. Our thorough genome annotation revealed Hox C genes previously hypothesized to have been lost, as well as distinct gene repertories of opsins and olfactory receptors that would be associated with adaptation to unique underwater niches. We also show the early establishment of the genetic machinery governing mammalian homoeostasis and reproduction at the jawed vertebrate ancestor. This study, supported by genomic, transcriptomic and epigenomic resources, provides a foundation for the comprehensive, molecular exploration of phenotypes unique to sharks and insights into the evolutionary origins of vertebrates.

@article{doi101038s4155901806735,
    author = "Hara, Yuichiro and Yamaguchi, Kazuaki and Onimaru, Koh and Kadota, Mitsutaka and Koyanagi, Mitsumasa and Keeley, Sean D. and Tatsumi, Kaori and Tanaka, Kaori and Motone, Fumio and Kageyama, Yuka and Nozu, Ryo and Adachi, Noritaka and Nishimura, Osamu and Nakagawa, Reiko and Tanegashima, Chiharu and Kiyatake, Itsuki and Matsumoto, Rui and Murakumo, Kiyomi and Nishida, Kiyonori and Terakita, Akihisa and Kuratani, Shigeru and Sato, Keiichi and Hyodo, Susumu and Kuraku, Shigehiro",
    title = "Shark genomes provide insights into elasmobranch evolution and the origin of vertebrates",
    year = "2018",
    journal = "Nature Ecology \& Evolution",
    abstract = "Modern cartilaginous fishes are divided into elasmobranchs (sharks, rays and skates) and chimaeras, and the lack of established whole-genome sequences for the former has prevented our understanding of early vertebrate evolution and the unique phenotypes of elasmobranchs. Here we present de novo whole-genome assemblies of brownbanded bamboo shark and cloudy catshark and an improved assembly of the whale shark genome. These relatively large genomes (3.8-6.7 Gbp) contain sparse distributions of coding genes and regulatory elements and exhibit reduced molecular evolutionary rates. Our thorough genome annotation revealed Hox C genes previously hypothesized to have been lost, as well as distinct gene repertories of opsins and olfactory receptors that would be associated with adaptation to unique underwater niches. We also show the early establishment of the genetic machinery governing mammalian homoeostasis and reproduction at the jawed vertebrate ancestor. This study, supported by genomic, transcriptomic and epigenomic resources, provides a foundation for the comprehensive, molecular exploration of phenotypes unique to sharks and insights into the evolutionary origins of vertebrates.",
    url = "https://doi.org/10.1038/s41559-018-0673-5",
    doi = "10.1038/s41559-018-0673-5",
    openalex = "W2894335751",
    references = "doi101002jez1402670309, doi101038s4155901704484"
}

Fishes are able to detect and perceive the hydrodynamic and physical environment they inhabit and process this sensory information to guide the resultant behaviour through their mechanosensory lateral-line system. This sensory system consists of up to several thousand neuromasts distributed across the entire body of the animal. Using the lateral-line system, fishes perceive water movements of both biotic and abiotic origin. The anatomy of the lateral-line system varies greatly between and within species. It is still a matter of debate as to how different lateral-line anatomies reflect adaptations to the hydrodynamic conditions to which fishes are exposed. While there are many accounts of lateral-line system adaptations for the detection of hydrodynamic signals in distinct behavioural contexts and environments for specific fish species, there is only limited knowledge on how the environment influences intra and interspecific variations in lateral-line morphology. Fishes live in a wide range of habitats with highly diverse hydrodynamic conditions, from pools and lakes and slowly moving deep-sea currents to turbulent and fast running rivers and rough coastal surf regions. Perhaps surprisingly, detailed characterisations of the hydrodynamic properties of natural water bodies are rare. In particular, little is known about the spatio-temporal patterns of the small-scale water motions that are most relevant for many fish behaviours, making it difficult to relate environmental stimuli to sensory system morphology and function. Humans use bodies of water extensively for recreational, industrial and domestic purposes and in doing so often alter the aquatic environment, such as through the release of toxicants, the blocking of rivers by dams and acoustic noise emerging from boats and construction sites. Although the effects of anthropogenic interferences are often not well understood or quantified, it seems obvious that they change not only water quality and appearance but also, they alter hydrodynamic conditions and thus the types of hydrodynamic stimuli acting on fishes. To date, little is known about how anthropogenic influences on the aquatic environment affect the morphology and function of sensory systems in general and the lateral-line system in particular. This review starts out by briefly describing naturally occurring hydrodynamic stimuli and the morphology and neurobiology of the fish lateral-line system. In the main part, adaptations of the fish lateral-line system for the detection and analysis of water movements during various behaviours are presented. Finally, anthropogenic influences on the aquatic environment and potential effects on the fish lateral-line system are discussed.

@article{doi101111jfb13966,
    author = "Mogdans, Joachim",
    title = "Sensory ecology of the fish lateral‐line system: Morphological and physiological adaptations for the perception of hydrodynamic stimuli",
    year = "2019",
    journal = "Journal of Fish Biology",
    abstract = "Fishes are able to detect and perceive the hydrodynamic and physical environment they inhabit and process this sensory information to guide the resultant behaviour through their mechanosensory lateral-line system. This sensory system consists of up to several thousand neuromasts distributed across the entire body of the animal. Using the lateral-line system, fishes perceive water movements of both biotic and abiotic origin. The anatomy of the lateral-line system varies greatly between and within species. It is still a matter of debate as to how different lateral-line anatomies reflect adaptations to the hydrodynamic conditions to which fishes are exposed. While there are many accounts of lateral-line system adaptations for the detection of hydrodynamic signals in distinct behavioural contexts and environments for specific fish species, there is only limited knowledge on how the environment influences intra and interspecific variations in lateral-line morphology. Fishes live in a wide range of habitats with highly diverse hydrodynamic conditions, from pools and lakes and slowly moving deep-sea currents to turbulent and fast running rivers and rough coastal surf regions. Perhaps surprisingly, detailed characterisations of the hydrodynamic properties of natural water bodies are rare. In particular, little is known about the spatio-temporal patterns of the small-scale water motions that are most relevant for many fish behaviours, making it difficult to relate environmental stimuli to sensory system morphology and function. Humans use bodies of water extensively for recreational, industrial and domestic purposes and in doing so often alter the aquatic environment, such as through the release of toxicants, the blocking of rivers by dams and acoustic noise emerging from boats and construction sites. Although the effects of anthropogenic interferences are often not well understood or quantified, it seems obvious that they change not only water quality and appearance but also, they alter hydrodynamic conditions and thus the types of hydrodynamic stimuli acting on fishes. To date, little is known about how anthropogenic influences on the aquatic environment affect the morphology and function of sensory systems in general and the lateral-line system in particular. This review starts out by briefly describing naturally occurring hydrodynamic stimuli and the morphology and neurobiology of the fish lateral-line system. In the main part, adaptations of the fish lateral-line system for the detection and analysis of water movements during various behaviours are presented. Finally, anthropogenic influences on the aquatic environment and potential effects on the fish lateral-line system are discussed.",
    url = "https://doi.org/10.1111/jfb.13966",
    doi = "10.1111/jfb.13966",
    openalex = "W2922278223",
    references = "doi10100797814612356063, doi101098rspb20160839"
}

-expressing dermal cells. Epidermal Noggin overexpression at E14.5 disrupted touch-dome formation but not hair-follicle specification, demonstrating a temporally distinct requirement for BMP signaling in placode-derived structures. Surprisingly, two neuronal populations preferentially targeted touch domes during development but only one persisted in mature touch domes. Finally, Keratin-17-expressing keratinocytes but not Merkel cells were necessary to establish innervation patterns during development. These findings identify key cell types and signaling pathways required for targeting Merkel-cell afferents to discrete mechanosensory compartments.

@article{doi107554elife42633,
    author = "Jenkins, Blair A. and Fontecilla, Natalia M. and Lu, Ping and Fuchs, Elaine and Lumpkin, Ellen A.",
    title = "The cellular basis of mechanosensory Merkel-cell innervation during development",
    year = "2019",
    journal = "eLife",
    abstract = "-expressing dermal cells. Epidermal Noggin overexpression at E14.5 disrupted touch-dome formation but not hair-follicle specification, demonstrating a temporally distinct requirement for BMP signaling in placode-derived structures. Surprisingly, two neuronal populations preferentially targeted touch domes during development but only one persisted in mature touch domes. Finally, Keratin-17-expressing keratinocytes but not Merkel cells were necessary to establish innervation patterns during development. These findings identify key cell types and signaling pathways required for targeting Merkel-cell afferents to discrete mechanosensory compartments.",
    url = "https://doi.org/10.7554/elife.42633",
    doi = "10.7554/elife.42633",
    openalex = "W2917631679",
    references = "doi101016jydbio201402016"
}

@article{wheeler2020anthropogenic,
    author = "Wheeler, Carolyn R. and Gervais, Connor R. and Johnson, Martijn S. and Vance, Shelby and Rosa, Rui and Mandelman, John W. and Rummer, Jodie L.",
    title = "Anthropogenic stressors influence reproduction and development in elasmobranch fishes",
    year = "2020",
    journal = "Reviews in Fish Biology and Fisheries",
    url = "https://doi.org/10.1007/s11160-020-09604-0",
    doi = "10.1007/s11160-020-09604-0",
    number = "2",
    openalex = "W3026967763",
    pages = "373-386",
    volume = "30",
    references = "doi101006jmsc20000724, doi101038srep46864, doi1010719780643109148, doi101086284913, doi101111gcb13903, doi101126scienceaac4722, doi101126scienceaan8048, doi101371journalpone0146756, doi107554elife00590, openalexw2530597942"
}

Abstract We develop a potentially widely applicable framework for analysing the vulnerability, resilience risk and exposure of chondrichthyan species to all types of anthropogenic stressors in the marine environment. The approach combines the three components of widely applied vulnerability analysis (exposure, sensitivity and adaptability) (ESA) with three components (exposure, susceptibility and productivity) (ESP) of our adaptation of productivity–susceptibility analysis (PSA). We apply our 12‐step ESA‒ESP analysis to evaluate the vulnerability (risk of a marked reduction of the population) of each of 132 chondrichthyan species in the Exclusive Economic Zone of southern Australia. The vulnerability relates to a species’ resilience to a spatial (or suitability) reduction of its habitats from exposure to up to eight climate change stressors. Vulnerability also relates to anthropogenic mortality added to natural mortality from exposure to the stressors of five types of fishing and seven other types of anthropogenic hazards. We use biological attributes as risk factors to evaluate risk related to resilience at the species or higher taxonomic level. We evaluate each species’ exposure to anthropogenic stressors by assigning it to one of six ecological groups based on its lifestyle (demersal versus pelagic) and habitat, defined by bathymetric range and substrates. We evaluate vulnerability for 11 scenarios: 2000–2006 when fishing effort peaked; 2018 following a decade of fisheries management reforms; low, medium and high standard future carbon dioxide equivalent emissions scenarios; and their six possible climate–fishing combinations. Our results demonstrate the value of refugia from fishing and how climate change exacerbates the risks from fishing.

@article{doi101111faf12571,
    author = "Walker, Terence I. and Day, Robert W. and Awruch, Cynthia A. and Bell, Justin D. and Braccini, Juan Matias and Dapp, Derek R. and Finotto, Licia and Frick, Lorenz H. and Garcés‐García, Karla C. and Guida, Leonardo and Huveneers, Charlie and Martins, Camila Leite and Rochowski, Bastien and Tovar‐Ávila, Javier and Trinnie, Fabian I. and Reina, Richard D.",
    title = "Ecological vulnerability of the chondrichthyan fauna of southern Australia to the stressors of climate change, fishing and other anthropogenic hazards",
    year = "2021",
    journal = "Fish and Fisheries",
    abstract = "Abstract We develop a potentially widely applicable framework for analysing the vulnerability, resilience risk and exposure of chondrichthyan species to all types of anthropogenic stressors in the marine environment. The approach combines the three components of widely applied vulnerability analysis (exposure, sensitivity and adaptability) (ESA) with three components (exposure, susceptibility and productivity) (ESP) of our adaptation of productivity–susceptibility analysis (PSA). We apply our 12‐step ESA‒ESP analysis to evaluate the vulnerability (risk of a marked reduction of the population) of each of 132 chondrichthyan species in the Exclusive Economic Zone of southern Australia. The vulnerability relates to a species’ resilience to a spatial (or suitability) reduction of its habitats from exposure to up to eight climate change stressors. Vulnerability also relates to anthropogenic mortality added to natural mortality from exposure to the stressors of five types of fishing and seven other types of anthropogenic hazards. We use biological attributes as risk factors to evaluate risk related to resilience at the species or higher taxonomic level. We evaluate each species’ exposure to anthropogenic stressors by assigning it to one of six ecological groups based on its lifestyle (demersal versus pelagic) and habitat, defined by bathymetric range and substrates. We evaluate vulnerability for 11 scenarios: 2000–2006 when fishing effort peaked; 2018 following a decade of fisheries management reforms; low, medium and high standard future carbon dioxide equivalent emissions scenarios; and their six possible climate–fishing combinations. Our results demonstrate the value of refugia from fishing and how climate change exacerbates the risks from fishing.",
    url = "https://doi.org/10.1111/faf.12571",
    doi = "10.1111/faf.12571",
    openalex = "W3170191348",
    references = "doi101007s11160020096040, wheeler2020anthropogenic"
}

Despite the long evolutionary history of this group, the challenges brought by the Anthropocene have been inflicting an extensive pressure over sharks and their relatives. Overexploitation has been driving a worldwide decline in elasmobranch populations, and rapid environmental change, triggered by anthropogenic activities, may further test this group's resilience. In this context, we searched the literature for peer-reviewed studies featuring a sustained (>24 h) and controlled exposure of elasmobranch species to warming, acidification, and/or deoxygenation: three of the most pressing symptoms of change in the ocean. In a standardized comparative framework, we conducted an array of mixed-model meta-analyses (based on 368 control-treatment contrasts from 53 studies) to evaluate the effects of these factors and their combination as experimental treatments. We further compared these effects across different attributes (lineages, climates, lifestyles, reproductive modes, and life stages) and assessed the direction of impact over a comprehensive set of biological responses (survival, development, growth, aerobic metabolism, anaerobic metabolism, oxygen transport, feeding, behavior, acid-base status, thermal tolerance, hypoxia tolerance, and cell stress). Based on the present findings, warming appears as the most influential factor, with clear directional effects, namely decreasing development time and increasing aerobic metabolism, feeding, and thermal tolerance. While warming influence was pervasive across attributes, acidification effects appear to be more context-specific, with no perceivable directional trends across biological responses apart from the necessary to achieve acid-base balance. Meanwhile, despite its potential for steep impacts, deoxygenation has been the most neglected factor, with data paucity ultimately precluding sound conclusions. Likewise, the implementation of multi-factor treatments has been mostly restricted to the combination of warming and acidification, with effects approximately matching those of warming. Despite considerable progress over recent years, research regarding the impact of these drivers on elasmobranchs lags behind other taxa, with more research required to disentangle many of the observed effects. Given the current levels of extinction risk and the quick pace of global change, it is further crucial that we integrate the knowledge accumulated through different scientific approaches into a holistic perspective to better understand how this group may fare in a changing ocean.

@article{doi103389fmars2021735377,
    author = "Santos, Catarina Pereira and Sampaio, Eduardo and Pereira, Beatriz P. and Pegado, Maria Rita and Borges, Francisco O. and Wheeler, Carolyn R. and Bouyoucos, Ian A. and Rummer, Jodie L. and Santos, Catarina and Rosa, Rui",
    title = "Elasmobranch Responses to Experimental Warming, Acidification, and Oxygen Loss—A Meta-Analysis",
    year = "2021",
    journal = "Frontiers in Marine Science",
    abstract = "Despite the long evolutionary history of this group, the challenges brought by the Anthropocene have been inflicting an extensive pressure over sharks and their relatives. Overexploitation has been driving a worldwide decline in elasmobranch populations, and rapid environmental change, triggered by anthropogenic activities, may further test this group's resilience. In this context, we searched the literature for peer-reviewed studies featuring a sustained (\>24 h) and controlled exposure of elasmobranch species to warming, acidification, and/or deoxygenation: three of the most pressing symptoms of change in the ocean. In a standardized comparative framework, we conducted an array of mixed-model meta-analyses (based on 368 control-treatment contrasts from 53 studies) to evaluate the effects of these factors and their combination as experimental treatments. We further compared these effects across different attributes (lineages, climates, lifestyles, reproductive modes, and life stages) and assessed the direction of impact over a comprehensive set of biological responses (survival, development, growth, aerobic metabolism, anaerobic metabolism, oxygen transport, feeding, behavior, acid-base status, thermal tolerance, hypoxia tolerance, and cell stress). Based on the present findings, warming appears as the most influential factor, with clear directional effects, namely decreasing development time and increasing aerobic metabolism, feeding, and thermal tolerance. While warming influence was pervasive across attributes, acidification effects appear to be more context-specific, with no perceivable directional trends across biological responses apart from the necessary to achieve acid-base balance. Meanwhile, despite its potential for steep impacts, deoxygenation has been the most neglected factor, with data paucity ultimately precluding sound conclusions. Likewise, the implementation of multi-factor treatments has been mostly restricted to the combination of warming and acidification, with effects approximately matching those of warming. Despite considerable progress over recent years, research regarding the impact of these drivers on elasmobranchs lags behind other taxa, with more research required to disentangle many of the observed effects. Given the current levels of extinction risk and the quick pace of global change, it is further crucial that we integrate the knowledge accumulated through different scientific approaches into a holistic perspective to better understand how this group may fare in a changing ocean.",
    url = "https://doi.org/10.3389/fmars.2021.735377",
    doi = "10.3389/fmars.2021.735377",
    openalex = "W3202172281",
    references = "doi101007s11160020096040, doi101016jzool2020125799, wheeler2020anthropogenic"
}

Some marine fishes are algae-feeding, and the microorganisms in their digestive tracts produce carbohydrate hydrolyzing enzymes such as agarose and fucosidase, which are potentially interesting resource for new functional enzymes. The purpose of this study was to establish a method for identifying and utilizing characteristic bacteria from the intestines of two algae-eating fish species: Andamia tetradactylus, which exclusively eats algae on the rock surface, and stellar rockskipper Entomacrodus stellifer, which feeds on both algae and invertebrates. We tested the species composition of the intestinal bacterial flora and found that Proteobacteria were commonly found both in species as in the common gut communities of marine fish, whereas Spirochaetes and Tenericutes occupied the flora of A. tetradactylus. We then performed anaerobic and aerobic cultures and isolated 34 and 44 strains including 48 strains belonged to Vibrio species from A. tetradactylus and E. stellifer. We observed that some Vibrio strains formed a clear boundary to avoid contacting other strains of bacteria. Whole-genome sequencing of such two Vibrio alginolyticus strains revealed two cyclic chromosomes commonly found in the genome of Vibrio species, and some unique genes encoding alginate lyase, chitinases, and type I-F CRISPR-associated endoribonuclease for the first time in Vibrio alginolyticus.

@article{doi101038s41598022085117,
    author = "Yoshida, Masaaki and Tanabe, Takuma and Akiyoshi, Hideo and Kawamukai, Makoto",
    title = "Gut microbiota analysis of Blenniidae fishes including an algae-eating fish and clear boundary formation among isolated Vibrio strains",
    year = "2022",
    journal = "Scientific Reports",
    abstract = "Some marine fishes are algae-feeding, and the microorganisms in their digestive tracts produce carbohydrate hydrolyzing enzymes such as agarose and fucosidase, which are potentially interesting resource for new functional enzymes. The purpose of this study was to establish a method for identifying and utilizing characteristic bacteria from the intestines of two algae-eating fish species: Andamia tetradactylus, which exclusively eats algae on the rock surface, and stellar rockskipper Entomacrodus stellifer, which feeds on both algae and invertebrates. We tested the species composition of the intestinal bacterial flora and found that Proteobacteria were commonly found both in species as in the common gut communities of marine fish, whereas Spirochaetes and Tenericutes occupied the flora of A. tetradactylus. We then performed anaerobic and aerobic cultures and isolated 34 and 44 strains including 48 strains belonged to Vibrio species from A. tetradactylus and E. stellifer. We observed that some Vibrio strains formed a clear boundary to avoid contacting other strains of bacteria. Whole-genome sequencing of such two Vibrio alginolyticus strains revealed two cyclic chromosomes commonly found in the genome of Vibrio species, and some unique genes encoding alginate lyase, chitinases, and type I-F CRISPR-associated endoribonuclease for the first time in Vibrio alginolyticus.",
    url = "https://doi.org/10.1038/s41598-022-08511-7",
    doi = "10.1038/s41598-022-08511-7",
    openalex = "W4221011340",
    references = "doi105962bhltitle992"
}

The evolution and development of the head have long captivated researchers due to the crucial role of the head as the gateway for sensory stimuli and the intricate structural complexity of the head. Although significant progress has been made in understanding head development in various vertebrate species, our knowledge of early human head ontogeny remains limited. Here, we used advanced whole-mount immunostaining and 3D imaging techniques to generate a comprehensive 3D cellular atlas of human head embryogenesis. We present detailed developmental series of diverse head tissues and cell types, including muscles, vasculature, cartilage, peripheral nerves, and exocrine glands. These datasets, accessible through a dedicated web interface, provide insights into human embryogenesis. We offer perspectives on the branching morphogenesis of human exocrine glands and unknown features of the development of neurovascular and skeletomuscular structures. These insights into human embryology have important implications for understanding craniofacial defects and neurological disorders and advancing diagnostic and therapeutic strategies.

@article{doi101016jcell202311013,
    author = "Blain, Raphaël and Couly, G and Shotar, Eimad and Blévinal, Joséphine and Toupin, Maryne and Favre, A. and Abjaghou, Ali and Inoue, M. and Hernández-Garzón, Edwin and Clarençon, Frédéric and Chalmel, Frédéric and Mazaud‐Guittot, Séverine and Giacobini, Paolo and Gitton, Yorick and Chédotal, Alain",
    title = "A tridimensional atlas of the developing human head",
    year = "2023",
    journal = "Cell",
    abstract = "The evolution and development of the head have long captivated researchers due to the crucial role of the head as the gateway for sensory stimuli and the intricate structural complexity of the head. Although significant progress has been made in understanding head development in various vertebrate species, our knowledge of early human head ontogeny remains limited. Here, we used advanced whole-mount immunostaining and 3D imaging techniques to generate a comprehensive 3D cellular atlas of human head embryogenesis. We present detailed developmental series of diverse head tissues and cell types, including muscles, vasculature, cartilage, peripheral nerves, and exocrine glands. These datasets, accessible through a dedicated web interface, provide insights into human embryogenesis. We offer perspectives on the branching morphogenesis of human exocrine glands and unknown features of the development of neurovascular and skeletomuscular structures. These insights into human embryology have important implications for understanding craniofacial defects and neurological disorders and advancing diagnostic and therapeutic strategies.",
    url = "https://doi.org/10.1016/j.cell.2023.11.013",
    doi = "10.1016/j.cell.2023.11.013",
    openalex = "W4389489563",
    references = "doi101002aja1000040106"
}