Echinoids

@article{rowe1899an7,
    author = "Rowe, A. W",
    title = "An analysis of the genus Micraster as determined by rigid zonal collecting from the zone of Rhynchonella cuvieri to that of Micraster cor-anguinum",
    year = "1899",
    journal = "Geological Society of London Quarterly Journal, v. 55, p. 494-547",
    note = "talkorigins\_source = {true}; raw\_reference = {Rowe, A. W., 1899, An analysis of the genus Micraster as determined by rigid zonal collecting from the zone of Rhynchonella cuvieri to that of Micraster cor-anguinum: Geological Society of London Quarterly Journal, v. 55, p. 494-547.}"
}

@misc{jackson1912phylogeny2,
    author = "Jackson, R. T",
    title = "Phylogeny of the echini, with a revision of the Paleozoic species",
    year = "1912",
    howpublished = "Boston Society of Natural History, Memoirs, v. 7, p. 1-491",
    note = "talkorigins\_source = {true}; raw\_reference = {Jackson, R. T., 1912, Phylogeny of the echini, with a revision of the Paleozoic species: Boston Society of Natural History, Memoirs, v. 7, p. 1-491.}"
}

@article{kermack1954a3,
    author = "Kermack, K. A",
    title = "A biometrical study of Micraster coranguinum and M. (Isomicraster) senonensis",
    year = "1954",
    journal = "Royal Society of London, Philosophical Transactions, Series B, v. 237, p. 375-428",
    note = "talkorigins\_source = {true}; raw\_reference = {Kermack, K. A., 1954, A biometrical study of Micraster coranguinum and M. (Isomicraster) senonensis: Royal Society of London, Philosophical Transactions, Series B, v. 237, p. 375-428.}"
}

Intraspecific variation in the echinoid genus Dendraster is studied by means of a statistical analysis of variation in the living species: D. excentricus. The character is analyzed in samples from 34 collections of D. excentricus. This character is prominent in current classifications of the genus. It is found that observed eccentricity data are biased by an allometric relation between eccentricity and test length. This allometry is described by an empirically derived curve. The parabolic function defining this allometric curve is used to eliminate the length bias from the eccentricity data. No systematic geographic variation is recognized in D. excentricus as reflected in the character eccentricity. However, the species may be divided into two ecological races on the basis of eccentricity. The race inhabiting sheltered bays is significantly less eccentric than the race living along the open coast. The eccentricity data for D. excentricus are employed in a review of the classification of the fossil members of the genus. The heretofore unrecognized allometry and ecological variation in Dendraster may explain some of the difficulties encountered in the fossil classification. It is found that there are greater differences in eccentricity between populations of D. excentricus than there are between species in the fossil record.

@article{doi10130674d705dd2b2111d78648000102c1865d,
    author = "Raup, David M.",
    title = "Dendraster; a problem in echinoid taxonomy",
    year = "1956",
    journal = "Journal of Sedimentary Research",
    abstract = "Intraspecific variation in the echinoid genus Dendraster is studied by means of a statistical analysis of variation in the living species: D. excentricus. The character is analyzed in samples from 34 collections of D. excentricus. This character is prominent in current classifications of the genus. It is found that observed eccentricity data are biased by an allometric relation between eccentricity and test length. This allometry is described by an empirically derived curve. The parabolic function defining this allometric curve is used to eliminate the length bias from the eccentricity data. No systematic geographic variation is recognized in D. excentricus as reflected in the character eccentricity. However, the species may be divided into two ecological races on the basis of eccentricity. The race inhabiting sheltered bays is significantly less eccentric than the race living along the open coast. The eccentricity data for D. excentricus are employed in a review of the classification of the fossil members of the genus. The heretofore unrecognized allometry and ecological variation in Dendraster may explain some of the difficulties encountered in the fossil classification. It is found that there are greater differences in eccentricity between populations of D. excentricus than there are between species in the fossil record.",
    url = "https://doi.org/10.1306/74d705dd-2b21-11d7-8648000102c1865d",
    doi = "10.1306/74d705dd-2b21-11d7-8648000102c1865d",
    openalex = "W2162072816"
}

@incollection{cooke1957echinoids,
    author = "Cooke, C. Wythe",
    title = "Echinoids of the Post-Paleozoic",
    year = "1957",
    booktitle = "Geological Society of America Memoirs",
    url = "https://doi.org/10.1130/mem67v2-p981",
    doi = "10.1130/mem67v2-p981",
    openalex = "W2506068491",
    pages = "981-982"
}

@incollection{cooper1957echinoids,
    author = "Cooper, G. Arthur",
    title = "Echinoids of the Paleozoic",
    year = "1957",
    booktitle = "Geological Society of America Memoirs",
    url = "https://doi.org/10.1130/mem67v2-p979",
    doi = "10.1130/mem67v2-p979",
    openalex = "W2491990152",
    pages = "979-980"
}

Abstract The fossil genus Micraster from the Chalk gives an excellent example of continuous evolution of individual characters. The changes, however, appear to be independent of changes in those environmental conditions which have left their mark in the formation of the sediment (changes in depth at which it was deposited, particle size, temperature, etc (Nichols 1956)). Consequently, these changes in the urchins probably reflect either a change in niche or an improvement in the adaptation of the animal in an effectively unchanged niche. To discover the significance of the changes, the following seven living species of British irregular echinoids have been studied in detail, both morphologically and functionally. Order Spatangoida: Spatangus purpureas, S. raschi, Echinocardium cordatum, E. pennatifidum, E. flavescens, Brissopsis lyrifera. Order Clypeastroida: Echinocyamus pusillus. The ciliary currents on the tests of these urchins are in general similar, except at the fascioles. Features not previously reported are, first, the existence in all the urchins of an apical eddy of currents to ensure that the genital products are not wafted into the mouth, and secondly, forwardly directed currents into the mouth flowing over the lip. The normal burrowing of three of the urchins, S. purpureus, S. raschi and E. cordatum, was observed. S. purpureus can burrow with its dorsal surface some 5 cm below the surface of the substratum, with no visible connexion with the sea water; water currents for respiration are apparently obtained through the interstices of the gravel particles in which it lives. The prehensile tube-feet of its subanal region build a double sanitary tube, each element originating at one lobe of the bilobed subanal fasciole. E. cordatum, observed both in aquaria and in the field, burrows to a maximum depth of about 18 cm, and maintains contact with the sea water via a respiratory funnel built by the tube-feet of the dorsal part of the anterior ambulacrum. A single sanitary tube is built, originating at the shield-shaped subanal fasciole. From the configuration of their subanal regions it is inferred that E. pennatifidum and E. flavescens also build single sanitary tubes, whereas B. lyrifera builds a double one. The main factor governing the number of tubes for sanitation is suggested to be the coherence of the substratum, those living in shell gravel and mud requiring only the same number of tube-feet to build two tubes as those living in sand require to build one; in consequence the shell-gravel and mud forms can attain a larger size. Some experimental evidence is presented for this hypothesis. S. raschi ploughs through the substratum with about half of its corona exposed above the surface; it attains a larger size than any other urchin studied, yet apparently builds only one subanal tube. The reason for this seems to be that since the respiratory tube-feet are not confined in a burrow, there is no need for a large soak-away for the respiratory water, and the sanitary device can be correspondingly smaller in cross-section. The feeding of all six spatangids was observed; in general they grasp a particleor cluster of particles of the substratum with the oral prehensile tube-feet, convey the material with its covering of organic matter to the mouth, and scrape it off against the spines surrounding the peristome so that it passes into the gut. Selection of food particles by weight occurs in those urchins normally inhabiting shell gravel (S. purpureus, E. pennatifidum, E. flavescens). The functional significance of the following morphological features of all the urchins is discussed: (i) number and arrangement of the fascioles providing augmentation of the ciliary currents on the test where they are specially needed; (ii) shape and arrangement of spines, for use in scraping, locomotion and burrow-building; (iii) division of labour among the tube-feet for feeding, burrow-building, respiration and sensation; (iv) depth of the anterior groove providing a channel for the passage of food currents from the dorsal surface to the mouth; (v) arrangement of the respiratory organs in the most efficient way for the type of burrow. The morphology of the various tube-feet of E. cordatum, and the pores from which they arise, is described. The disks of the feeding tube-feet have a velvet-like pile of papillae for collecting the sediment, whereas those of the burrow-building tube-feet tend to allow space in the centre so that the fringe of papillae can fold in during retraction. The feeding tube-feet, extending at all angles to the test, have wide bases to their stems, whereas those whose extensions are mainly perpendicular to the test are much narrower. The main features of Micraster and the closely related subgenus Isomicraster are described, and the work of Rowe and Kermack on the evolution of the group is reviewed. The probable effect of other animals living in or feeding on the sea bottom at the time of these fossils is described. The number of pore-pairs in the petaloid parts of the paired ambulacra (those which gave rise to the respiratory tube-feet) have been examined in specimens from successive stages of the Micraster and Isomicraster series. There is a progressive increase in number in the main Micraster line with time, while the Isomicraster series have many more than the highest number of these. The increase in the main line is interpreted as enabling successive populations to burrow more and more deeply and is confirmed by changes in other features, particularly the increase in surface area by ornamentation to increase the concentration of cilia. The higher number in the isomicrasters is interpreted as enabling a reduction in size of the tube-feet as a countermeasure to predation, thus paralleling such living forms as S. raschi, and this is also supported by other features, particularly the reduction in ciliary currents in the subanal region. In the main Micraster phylum changes in the peristomial region, in the position of the mouth, degree of development of the labrum and the depth of the anterior groove suggest by comparison with the mode of life of living urchins a gradually increasing reliance on a ciliary mode of feeding at the expense of that of using tube-feet. When Micraster appears in the cuvieri zone as M. leskei it is a rare urchin. Its features suggest that it burrowed only shallowly. In the next two zones the shallow-burrowing features are retained by extremes on one side (corbvis), while features suggesting deeper burrowing gradually become more common and more pronounced on the other (cortestudinarium). At the top of the planus zone the shallow-burrowing forms die out, but the deeper burrowers persist up to the testudinarius zone, the features that suggest deeper burrowing becoming even more marked (coranguinum). At the same time, following the disappearance of the shallow burrowers, a partial burrower, senonensis, appears, probably by immigration. Considerable interbreeding occurs between this, the so-called Isomicraster line, and the main line and at the most it should only be considered subspecifically distinct from the micrasters. Similarly, in the mucronata zone of Norfolk intermediates occur between glyphus and its contemporary member of the isomicrasters, stolleyi, though from the small sample available and because of the lack of evidence from intermediate strata it is not possible to say whether the situation parallels the micrasters and isomicrasters of the south of England (i.e. that stolleyi is an immigrant), or whether both these forms have re-invaded the English area after becoming subspecifically distinct outside it.

@article{doi101098rstb19590007,
    author = "Nichols, David",
    title = "Changes in the chalk heart-urchin Micraster Interpreted in relation to living forms",
    year = "1959",
    journal = "Philosophical transactions of the Royal Society of London. Series B, Biological sciences",
    abstract = "Abstract The fossil genus Micraster from the Chalk gives an excellent example of continuous evolution of individual characters. The changes, however, appear to be independent of changes in those environmental conditions which have left their mark in the formation of the sediment (changes in depth at which it was deposited, particle size, temperature, etc (Nichols 1956)). Consequently, these changes in the urchins probably reflect either a change in niche or an improvement in the adaptation of the animal in an effectively unchanged niche. To discover the significance of the changes, the following seven living species of British irregular echinoids have been studied in detail, both morphologically and functionally. Order Spatangoida: Spatangus purpureas, S. raschi, Echinocardium cordatum, E. pennatifidum, E. flavescens, Brissopsis lyrifera. Order Clypeastroida: Echinocyamus pusillus. The ciliary currents on the tests of these urchins are in general similar, except at the fascioles. Features not previously reported are, first, the existence in all the urchins of an apical eddy of currents to ensure that the genital products are not wafted into the mouth, and secondly, forwardly directed currents into the mouth flowing over the lip. The normal burrowing of three of the urchins, S. purpureus, S. raschi and E. cordatum, was observed. S. purpureus can burrow with its dorsal surface some 5 cm below the surface of the substratum, with no visible connexion with the sea water; water currents for respiration are apparently obtained through the interstices of the gravel particles in which it lives. The prehensile tube-feet of its subanal region build a double sanitary tube, each element originating at one lobe of the bilobed subanal fasciole. E. cordatum, observed both in aquaria and in the field, burrows to a maximum depth of about 18 cm, and maintains contact with the sea water via a respiratory funnel built by the tube-feet of the dorsal part of the anterior ambulacrum. A single sanitary tube is built, originating at the shield-shaped subanal fasciole. From the configuration of their subanal regions it is inferred that E. pennatifidum and E. flavescens also build single sanitary tubes, whereas B. lyrifera builds a double one. The main factor governing the number of tubes for sanitation is suggested to be the coherence of the substratum, those living in shell gravel and mud requiring only the same number of tube-feet to build two tubes as those living in sand require to build one; in consequence the shell-gravel and mud forms can attain a larger size. Some experimental evidence is presented for this hypothesis. S. raschi ploughs through the substratum with about half of its corona exposed above the surface; it attains a larger size than any other urchin studied, yet apparently builds only one subanal tube. The reason for this seems to be that since the respiratory tube-feet are not confined in a burrow, there is no need for a large soak-away for the respiratory water, and the sanitary device can be correspondingly smaller in cross-section. The feeding of all six spatangids was observed; in general they grasp a particleor cluster of particles of the substratum with the oral prehensile tube-feet, convey the material with its covering of organic matter to the mouth, and scrape it off against the spines surrounding the peristome so that it passes into the gut. Selection of food particles by weight occurs in those urchins normally inhabiting shell gravel (S. purpureus, E. pennatifidum, E. flavescens). The functional significance of the following morphological features of all the urchins is discussed: (i) number and arrangement of the fascioles providing augmentation of the ciliary currents on the test where they are specially needed; (ii) shape and arrangement of spines, for use in scraping, locomotion and burrow-building; (iii) division of labour among the tube-feet for feeding, burrow-building, respiration and sensation; (iv) depth of the anterior groove providing a channel for the passage of food currents from the dorsal surface to the mouth; (v) arrangement of the respiratory organs in the most efficient way for the type of burrow. The morphology of the various tube-feet of E. cordatum, and the pores from which they arise, is described. The disks of the feeding tube-feet have a velvet-like pile of papillae for collecting the sediment, whereas those of the burrow-building tube-feet tend to allow space in the centre so that the fringe of papillae can fold in during retraction. The feeding tube-feet, extending at all angles to the test, have wide bases to their stems, whereas those whose extensions are mainly perpendicular to the test are much narrower. The main features of Micraster and the closely related subgenus Isomicraster are described, and the work of Rowe and Kermack on the evolution of the group is reviewed. The probable effect of other animals living in or feeding on the sea bottom at the time of these fossils is described. The number of pore-pairs in the petaloid parts of the paired ambulacra (those which gave rise to the respiratory tube-feet) have been examined in specimens from successive stages of the Micraster and Isomicraster series. There is a progressive increase in number in the main Micraster line with time, while the Isomicraster series have many more than the highest number of these. The increase in the main line is interpreted as enabling successive populations to burrow more and more deeply and is confirmed by changes in other features, particularly the increase in surface area by ornamentation to increase the concentration of cilia. The higher number in the isomicrasters is interpreted as enabling a reduction in size of the tube-feet as a countermeasure to predation, thus paralleling such living forms as S. raschi, and this is also supported by other features, particularly the reduction in ciliary currents in the subanal region. In the main Micraster phylum changes in the peristomial region, in the position of the mouth, degree of development of the labrum and the depth of the anterior groove suggest by comparison with the mode of life of living urchins a gradually increasing reliance on a ciliary mode of feeding at the expense of that of using tube-feet. When Micraster appears in the cuvieri zone as M. leskei it is a rare urchin. Its features suggest that it burrowed only shallowly. In the next two zones the shallow-burrowing features are retained by extremes on one side (corbvis), while features suggesting deeper burrowing gradually become more common and more pronounced on the other (cortestudinarium). At the top of the planus zone the shallow-burrowing forms die out, but the deeper burrowers persist up to the testudinarius zone, the features that suggest deeper burrowing becoming even more marked (coranguinum). At the same time, following the disappearance of the shallow burrowers, a partial burrower, senonensis, appears, probably by immigration. Considerable interbreeding occurs between this, the so-called Isomicraster line, and the main line and at the most it should only be considered subspecifically distinct from the micrasters. Similarly, in the mucronata zone of Norfolk intermediates occur between glyphus and its contemporary member of the isomicrasters, stolleyi, though from the small sample available and because of the lack of evidence from intermediate strata it is not possible to say whether the situation parallels the micrasters and isomicrasters of the south of England (i.e. that stolleyi is an immigrant), or whether both these forms have re-invaded the English area after becoming subspecifically distinct outside it.",
    url = "https://doi.org/10.1098/rstb.1959.0007",
    doi = "10.1098/rstb.1959.0007",
    openalex = "W2061714264"
}

All of these species are restricted to the Paleocene. The fauna.includes several genera reminiscent of the Cretaceous, notably Hemiaster, Holaster, and Echinocorys, but Echantlvus and Linthia suggest the Eocene. The new genus Rhopostoma was formerly included in the Cretaceous genus Tr-ematopygus. EOCENE FAUNAS Since the transfer of the Midway group to the Paleocene, the Eocene series has comprised only three divisions, the Wilcox group of early Eocene age, the Claiborne group of middle Eocene 'age, and the Jackson group of late Eocene age. Each of these has its distinctive echinoid fauna., Early Eocene species.-Only one species, Ewrhodia? elbana Cooke, is now referred to the early Eocene. It I

@article{doi103133pp321,
    author = "Cooke, C. Wythe",
    title = "Cenozoic echinoids of eastern United States",
    year = "1959",
    journal = "USGS professional paper",
    abstract = "All of these species are restricted to the Paleocene. The fauna.includes several genera reminiscent of the Cretaceous, notably Hemiaster, Holaster, and Echinocorys, but Echantlvus and Linthia suggest the Eocene. The new genus Rhopostoma was formerly included in the Cretaceous genus Tr-ematopygus. EOCENE FAUNAS Since the transfer of the Midway group to the Paleocene, the Eocene series has comprised only three divisions, the Wilcox group of early Eocene age, the Claiborne group of middle Eocene 'age, and the Jackson group of late Eocene age. Each of these has its distinctive echinoid fauna., Early Eocene species.-Only one species, Ewrhodia? elbana Cooke, is now referred to the early Eocene. It I",
    url = "https://doi.org/10.3133/pp321",
    doi = "10.3133/pp321",
    openalex = "W134030082",
    references = "cooke1957echinoids, doi101017s0016756800085575, doi101111j109636421889tb01431x, doi101130gsab35827, doi10130674d705dd2b2111d78648000102c1865d, doi103931erara74066, doi105281zenodo16478164, doi105962bhltitle54733, openalexw2266779600, openalexw2524329691, openalexw2613659048"
}

@article{nichols1959changes5,
    author = "Nichols, D",
    title = "Changes in the Chalk heart-urchin Micraster interpreted in relation to living forms",
    year = "1959",
    journal = "Royal Society of London, Philosophical Transactions, Series B, v. 242, p. 347-437",
    note = "talkorigins\_source = {true}; raw\_reference = {Nichols, D., 1959, Changes in the Chalk heart-urchin Micraster interpreted in relation to living forms: Royal Society of London, Philosophical Transactions, Series B, v. 242, p. 347-437.}"
}

@misc{nichols1959mode6,
    author = "Nichols, D",
    title = "Mode of life and taxonomy in irregular sea-urchins",
    year = "1959",
    howpublished = "Systemists Association, v. 3, p. 61-80",
    note = "talkorigins\_source = {true}; raw\_reference = {Nichols, D., 1959, Mode of life and taxonomy in irregular sea-urchins: Systemists Association, v. 3, p. 61-80.}"
}

@book{hall1962evolution1,
    author = "Hall, C. A. and Jr",
    title = "Evolution of the echinoid genus Astrodapsis",
    year = "1962",
    publisher = "University of California Publications in Geological Science, v. 40, p. 47- 180",
    note = "talkorigins\_source = {true}; raw\_reference = {Hall, C. A., Jr., 1962, Evolution of the echinoid genus Astrodapsis: University of California Publications in Geological Science, v. 40, p. 47- 180.}"
}

@article{kier1965evolutionary4,
    author = "Kier, P. M",
    title = "Evolutionary trends in Paleozoic echinoids",
    year = "1965",
    journal = "Journal of Paleontology, v. 39, p. 436-465",
    note = "talkorigins\_source = {true}; raw\_reference = {Kier, P. M., 1965, Evolutionary trends in Paleozoic echinoids: Journal of Paleontology, v. 39, p. 436-465.}"
}

Many evolutionary trends are described in the post-Paleozoic echinoids and their functional advantages are discussed. In the ambulacra, the compound plate first appeared in the Late Triassic, becoming more pronounced during the Mesozoic, and reaching its zenith in the Cenozoic. Compounding enabled the echinoid to have more numerous tubefeet, strengthened the test, and increased the size of the ambulacral tubercles and spines. These larger spines provided greater protection from predators and faster locomotion. Petals first appeared in the Middle Jurassic and were developed for more efficient respiration. The first depressed petals occurred in the Late Jurassic, and by Late Cretaceous many echinoids had depressed petals culminating in deep petals in the Cenozoic. These depressions channeled water over the respiratory tubefeet, increased the width of the ambulacra and their tubefeet, and enabled these tubefeet to be protected from predators by the arching of spines over them. An anterior groove is slightly developed by the Middle Jurassic, distinct in the Cretaceous, and deepest in the Cenozoic. This groove provided a passage for food, and shelter for the large penicillate tubefeet. Phyllodes first occur in the Lower Jurassic in both the regular and irregular echinoids. During the Mesozoic the number of pores in the phyllodes in the irregular echinoids was reduced, and in most species one pore was eliminated of a porepair. The phyllodes provided a large number of feeding tubefeet near the peristome. In the apical system of the irregular echinoids, the periproct broke out during the Lower Jurassic. Its movement posteriorly served to separate the echinoid's excrement from its feeding and respiratory areas. The number of genital plates was reduced to a single plate in the cassiduloids by the Late Cretaceous, but this reduction occurred later in the holasteroids and spatangoids; many species living today have more than one genital plate. The Triassic and Early Jurassic echinoids were small; but during the latter part of the Jurassic, larger species occur, particularly among the irregulars and echinothurioids. All the Triassic echinoids except one were circular in marginal outline, but during the Jurassic the test in many irregulars became elongate enabling the echinoid to develop unidirectional movement. The flattening of the test permitted the echinoid to cover its test more easily, making the animal less conspicuous, less affected by wave motion, and placing more of the food-gathering tubefeet in contact with the seafloor. The Triassic lantern had grooved teeth and a shallow foramen, but by the Lower Jurassic some lanterns had a deeper foramen magnum. By the Middle Jurassic keeled teeth are present, and by the Late Cretaceous some lanterns have joined epiphyses. These changes permitted the lantern to be more mobile and strengthened the teeth and epiphyses. The lantern supports in all Triassic echinoids are outgrowths of interambulacral plates, but in the Lower Jurassic many species have ambulacral supports. By the Middle Jurassic these supports are joined together in some species to form an arch. These changes also increased the mobility and power of movement of the lantern. Gill notches first appeared in the Lower Jurassic (Hettangian) and were well developed by the Toarcian. The tubercles and their spines were large in the Triassic and gradually decreased in size in some species through the Mesozoic. This reduction enabled these echinoids with smaller spines to cover their tests with sediment. The rate of introduction of new plates was low in the Triassic, increasing during the Jurassic. This increase was mainly in the ambulacra and served to increase the number of tubefeet. Among the holasteroids-spatangoids some of the ventral interambulacral plates increased in size relative to adjacent plates during the Mesozoic and Cenozoic forming the labrum and plastron. These changes permitted the development of the “heart-shaped” test, and an anterior shift of the peristome. Diversity of echinoids increased since the Triassic with the development of different kinds of echinoids able to inhabit many varied habitats. All Triassic echinoids lived on top of the substrate, but in the Jurassic irregular echinoids began to burrow in the sediment. They increased in number of species during the Mesozoic and now are more numerous in species than the regular echinoids. The difference between Jurassic and Triassic species is not as abrupt as formerly thought, and all Jurassic echinoids are considered to have had a cidaroid ancestor.

@article{kier1974evolutionary,
    author = "Kier, Porter M.",
    title = "Evolutionary Trends and Their Functional Significance in the Post-Paleozoic Echinoids",
    year = "1974",
    journal = "Journal of Paleontology",
    abstract = "Many evolutionary trends are described in the post-Paleozoic echinoids and their functional advantages are discussed. In the ambulacra, the compound plate first appeared in the Late Triassic, becoming more pronounced during the Mesozoic, and reaching its zenith in the Cenozoic. Compounding enabled the echinoid to have more numerous tubefeet, strengthened the test, and increased the size of the ambulacral tubercles and spines. These larger spines provided greater protection from predators and faster locomotion. Petals first appeared in the Middle Jurassic and were developed for more efficient respiration. The first depressed petals occurred in the Late Jurassic, and by Late Cretaceous many echinoids had depressed petals culminating in deep petals in the Cenozoic. These depressions channeled water over the respiratory tubefeet, increased the width of the ambulacra and their tubefeet, and enabled these tubefeet to be protected from predators by the arching of spines over them. An anterior groove is slightly developed by the Middle Jurassic, distinct in the Cretaceous, and deepest in the Cenozoic. This groove provided a passage for food, and shelter for the large penicillate tubefeet. Phyllodes first occur in the Lower Jurassic in both the regular and irregular echinoids. During the Mesozoic the number of pores in the phyllodes in the irregular echinoids was reduced, and in most species one pore was eliminated of a porepair. The phyllodes provided a large number of feeding tubefeet near the peristome. In the apical system of the irregular echinoids, the periproct broke out during the Lower Jurassic. Its movement posteriorly served to separate the echinoid's excrement from its feeding and respiratory areas. The number of genital plates was reduced to a single plate in the cassiduloids by the Late Cretaceous, but this reduction occurred later in the holasteroids and spatangoids; many species living today have more than one genital plate. The Triassic and Early Jurassic echinoids were small; but during the latter part of the Jurassic, larger species occur, particularly among the irregulars and echinothurioids. All the Triassic echinoids except one were circular in marginal outline, but during the Jurassic the test in many irregulars became elongate enabling the echinoid to develop unidirectional movement. The flattening of the test permitted the echinoid to cover its test more easily, making the animal less conspicuous, less affected by wave motion, and placing more of the food-gathering tubefeet in contact with the seafloor. The Triassic lantern had grooved teeth and a shallow foramen, but by the Lower Jurassic some lanterns had a deeper foramen magnum. By the Middle Jurassic keeled teeth are present, and by the Late Cretaceous some lanterns have joined epiphyses. These changes permitted the lantern to be more mobile and strengthened the teeth and epiphyses. The lantern supports in all Triassic echinoids are outgrowths of interambulacral plates, but in the Lower Jurassic many species have ambulacral supports. By the Middle Jurassic these supports are joined together in some species to form an arch. These changes also increased the mobility and power of movement of the lantern. Gill notches first appeared in the Lower Jurassic (Hettangian) and were well developed by the Toarcian. The tubercles and their spines were large in the Triassic and gradually decreased in size in some species through the Mesozoic. This reduction enabled these echinoids with smaller spines to cover their tests with sediment. The rate of introduction of new plates was low in the Triassic, increasing during the Jurassic. This increase was mainly in the ambulacra and served to increase the number of tubefeet. Among the holasteroids-spatangoids some of the ventral interambulacral plates increased in size relative to adjacent plates during the Mesozoic and Cenozoic forming the labrum and plastron. These changes permitted the development of the “heart-shaped” test, and an anterior shift of the peristome. Diversity of echinoids increased since the Triassic with the development of different kinds of echinoids able to inhabit many varied habitats. All Triassic echinoids lived on top of the substrate, but in the Jurassic irregular echinoids began to burrow in the sediment. They increased in number of species during the Mesozoic and now are more numerous in species than the regular echinoids. The difference between Jurassic and Triassic species is not as abrupt as formerly thought, and all Jurassic echinoids are considered to have had a cidaroid ancestor.",
    url = "https://doi.org/10.1017/s0022336000061321",
    doi = "10.1017/s0022336000061321",
    number = "S5",
    openalex = "W2947356994",
    pages = "1-95",
    volume = "48",
    references = "doi101017s0025315400017574, doi101098rstb19590007, doi101126science17740541065, doi105962bhltitle11376, doi105962bhltitle30642, doi105962bhltitle4630, doi105962bhltitle54256, openalexw137635259, openalexw1522518756, openalexw2603113571"
}

The fossil record of echinoids is poor because soon after death they break apart into isolated plates. In the present seas regular echinoid species outnumber irregular species; whereas, in the Tertiary only 20% of the known echinoid species are regular. This suggests that regular echinoids are less likely to be preserved than irregular echinoids. The tests of regular echinoids are exposed to scavengers and currents upon their death, but irregular echinoids generally live buried in the sediment and are protected from these destructive forces. Furthermore, the tests of the regular echinoids lack the calcareous supports found in some irregular echinoids. The gut is not filled with sediment and its apical system is generally larger and more fragile. Finally, many regular echinoids live in environments less likely to be preserved in the sedimentary record. Although the irregular echinoid is more likely to be fossilized, its record is poor during some periods in the past. Although 1,014 irregular echinoid species are known from the Eocene, only 83 species are known from the Paleocene and only 343 are known from the Oligocene. Is this reduction because fewer species lived then or because they have not been preserved?

@article{doi101017s0094837300005248,
    author = "Kier, Porter M.",
    title = "The poor fossil record of the regular echinoid",
    year = "1977",
    journal = "Paleobiology",
    abstract = "The fossil record of echinoids is poor because soon after death they break apart into isolated plates. In the present seas regular echinoid species outnumber irregular species; whereas, in the Tertiary only 20\% of the known echinoid species are regular. This suggests that regular echinoids are less likely to be preserved than irregular echinoids. The tests of regular echinoids are exposed to scavengers and currents upon their death, but irregular echinoids generally live buried in the sediment and are protected from these destructive forces. Furthermore, the tests of the regular echinoids lack the calcareous supports found in some irregular echinoids. The gut is not filled with sediment and its apical system is generally larger and more fragile. Finally, many regular echinoids live in environments less likely to be preserved in the sedimentary record. Although the irregular echinoid is more likely to be fossilized, its record is poor during some periods in the past. Although 1,014 irregular echinoid species are known from the Eocene, only 83 species are known from the Paleocene and only 343 are known from the Oligocene. Is this reduction because fewer species lived then or because they have not been preserved?",
    url = "https://doi.org/10.1017/s0094837300005248",
    doi = "10.1017/s0094837300005248",
    openalex = "W2212209098",
    references = "doi101017s0094837300002232, doi101111j150239311972tb00852x, doi10113000167606197586243eosbca20co2, doi10130683d923e816c711d78645000102c1865d, doi10130683d923ed16c711d78645000102c1865d, doi105479si00810282206, openalexw2603991543, openalexw2800093945, openalexw2995010560"
}

The mid-Paleozoic was punctuated by a rapid radiation of durophagous (shell-crushing) predators. These new predators were primarily placoderm and chondrichthyan fishes but probably also included phyllocarid and eumalacostracan arthropods. Coincident with the radiation of these durophages, beginning in the mid-Devonian, there was an increase in the frequency of predation-resistant morphologies in a variety of marine invertebrate taxa. Among bellerophontid molluscs, disjunct coiling disappeared and umbilici became less common while the frequency of genera with sculpture increased. The abundance of brachiopod genera with spines on one or both valves increased dramatically. Sculpture became more pronounced and common among genera of coiled nautiloids. Inadunate and camerate crinoids showed a marked increase in spinosity, and all three crinoid subclasses tended to develop thicker thecal plates. Trends toward increasing relative frequencies of predation-resistant features were formed in different ways. Bellerophontid genera lacking predation-resistant features tended to go extinct, leaving the sculptured, tighdy coiled forms as the predominant forms. Among Brachiopoda, the radiation of productids provided the tremendous increase in numbers of spinose genera. Among crinoids, predation-resistant features were acquired through evolution within established clades. These observations suggest that predation by shell-crushing predators has been an important control on the morphology and composition of the marine invertebrate fauna since at least the Middle Devonian. The mid-Paleozoic radiation of durophages and response of the marine fauna was in many respects similar to events of the Mesozoic Marine Revolution, in effect, the Paleozoic precursor to that event.

@article{doi101017s0094837300008174,
    author = "Signor, Philip W. and Brett, Carlton E.",
    title = "The mid-Paleozoic precursor to the Mesozoic marine revolution",
    year = "1984",
    journal = "Paleobiology",
    abstract = "The mid-Paleozoic was punctuated by a rapid radiation of durophagous (shell-crushing) predators. These new predators were primarily placoderm and chondrichthyan fishes but probably also included phyllocarid and eumalacostracan arthropods. Coincident with the radiation of these durophages, beginning in the mid-Devonian, there was an increase in the frequency of predation-resistant morphologies in a variety of marine invertebrate taxa. Among bellerophontid molluscs, disjunct coiling disappeared and umbilici became less common while the frequency of genera with sculpture increased. The abundance of brachiopod genera with spines on one or both valves increased dramatically. Sculpture became more pronounced and common among genera of coiled nautiloids. Inadunate and camerate crinoids showed a marked increase in spinosity, and all three crinoid subclasses tended to develop thicker thecal plates. Trends toward increasing relative frequencies of predation-resistant features were formed in different ways. Bellerophontid genera lacking predation-resistant features tended to go extinct, leaving the sculptured, tighdy coiled forms as the predominant forms. Among Brachiopoda, the radiation of productids provided the tremendous increase in numbers of spinose genera. Among crinoids, predation-resistant features were acquired through evolution within established clades. These observations suggest that predation by shell-crushing predators has been an important control on the morphology and composition of the marine invertebrate fauna since at least the Middle Devonian. The mid-Paleozoic radiation of durophages and response of the marine fauna was in many respects similar to events of the Mesozoic Marine Revolution, in effect, the Paleozoic precursor to that event.",
    url = "https://doi.org/10.1017/s0094837300008174",
    doi = "10.1017/s0094837300008174",
    openalex = "W2283588956",
    references = "doi1010079781468464658, doi101017s0094837300005352, doi101038scientificamerican0779122, doi101086282400, doi101086627905, doi101111j155856461979tb04722x, doi101126science2034379458, doi101126science21545391501, doi1023071441916, doi105281zenodo16490103, doi105860choice293880, doi105962bhltitle52081, doi105962bhltitle7199, openalexw1549886310, openalexw1869415094, thomson1969the"
}

A three-phase kinetic model with time-specific perturbations is used to describe large-scale patterns in the diversification of Phanerozoic marine families. The basic model assumes that the Cambrian, Paleozoic, and Modern evolutionary faunas each diversified logistically as a consequence of early exponential growth and of later slowing of growth as the ecosystems became filled; it also assumes interaction among the evolutionary faunas such that expansion of the combined diversities of all three faunas above any single fauna's equilibrium caused that fauna's diversity to begin to decline. This basic model adequately describes the diversification of the evolutionary faunas through the Paleozoic Era as well as the asymmetrical rise and fall of background extinction rates through the entire Phanerozoic. Declines in diversity and changes in faunal dominance associated with mass extinctions can be accommodated in the model with short-term accelerations in extinction rates or declines in equilibria. Such accelerations, or perturbations, cause diversity to decline exponentially and then to rebound sigmoidally following release. The amount of decline is dependent on the magnitude and duration of the perturbation, the timing of the perturbation with respect to the diversification of the system, and the system's initial per-taxon rates of diversification and turnover. When applied to the three-phase model, such perturbations describe the changes in diversity and faunal dominance during and after major mass extinctions, the long-term rise in total diversity following the Late Permian and Norian mass extinctions, and the peculiar diversification and then decline of the remnants of the Paleozoic fauna during the Mesozoic and Cenozoic Eras. The good fit of this model to data on Phanerozoic familial diversity suggests that many of the large-scale patterns of diversification seen in the marine fossil record of animal families are simple consequences of nonlinear interrelationships among a small number of parameters that are intrinsic to the evolutionary faunas and are largely (but not completely) invariant through time.

@article{doi101017s0094837300008186,
    author = "Sepkoski, J. John",
    title = "A kinetic model of Phanerozoic taxonomic diversity. III. Post-Paleozoic families and mass extinctions",
    year = "1984",
    journal = "Paleobiology",
    abstract = "A three-phase kinetic model with time-specific perturbations is used to describe large-scale patterns in the diversification of Phanerozoic marine families. The basic model assumes that the Cambrian, Paleozoic, and Modern evolutionary faunas each diversified logistically as a consequence of early exponential growth and of later slowing of growth as the ecosystems became filled; it also assumes interaction among the evolutionary faunas such that expansion of the combined diversities of all three faunas above any single fauna's equilibrium caused that fauna's diversity to begin to decline. This basic model adequately describes the diversification of the evolutionary faunas through the Paleozoic Era as well as the asymmetrical rise and fall of background extinction rates through the entire Phanerozoic. Declines in diversity and changes in faunal dominance associated with mass extinctions can be accommodated in the model with short-term accelerations in extinction rates or declines in equilibria. Such accelerations, or perturbations, cause diversity to decline exponentially and then to rebound sigmoidally following release. The amount of decline is dependent on the magnitude and duration of the perturbation, the timing of the perturbation with respect to the diversification of the system, and the system's initial per-taxon rates of diversification and turnover. When applied to the three-phase model, such perturbations describe the changes in diversity and faunal dominance during and after major mass extinctions, the long-term rise in total diversity following the Late Permian and Norian mass extinctions, and the peculiar diversification and then decline of the remnants of the Paleozoic fauna during the Mesozoic and Cenozoic Eras. The good fit of this model to data on Phanerozoic familial diversity suggests that many of the large-scale patterns of diversification seen in the marine fossil record of animal families are simple consequences of nonlinear interrelationships among a small number of parameters that are intrinsic to the evolutionary faunas and are largely (but not completely) invariant through time.",
    url = "https://doi.org/10.1017/s0094837300008186",
    doi = "10.1017/s0094837300008186",
    openalex = "W2221600847",
    references = "doi1010079781475707403, doi1010160012825272900724, doi1010160031018281900924, doi101017s0094837300003778, doi101017s0094837300004917, doi101017s0094837300004929, doi101017s009483730000508x, doi101017s0094837300005236, doi101017s0094837300005352, doi101017s0094837300005649, doi101017s0094837300005972, doi101017s0094837300006539, doi101017s0094837300008174, doi101038260204c0, doi101038293435a0, doi101038303614a0, doi101073pnas722646, doi101073pnas813801, doi101086627905, doi101111j1469185x1983tb00380x, doi101111j150239311977tb00628x, doi101126science2064415217, doi101126science21545391501, doi101126science2164542173, doi101126science22246281123, doi101130spe89p63, doi1015159780691206912, doi102110pec77250019, doi1023071441916, doi1023072412725, jablonski1983larval, openalexw2145250129, openalexw2989049194"
}

Phylogenetic analysis of a data matrix of 86 skeletal characteristics, and of the first 400 bases of the 5’ end of the large subunit ribosomal RNA gene produce congruent cladograms for 11 extant echinoids. Based on these cladistic analyses the great majority of morphologic and molecular apomorphies can be placed in one of 18 independent geological time intervals. When the cladogram is calibrated using the fossil record of post-Paleozoic echinoids, rates of molecular change in 28S rRNA can be calculated and compared with estimated rates of morphological evolution. Morphological and molecular apomorphies acquired in each time interval both correlate moderately strongly with time elapsed, but less strongly with one another. As expected, morphological rates vary considerably over time and between sister groups, but so too do molecular rates. When averaged over all echinoids studied, the number of morphological apomorphies accrued yields a slightly higher Spearman Rank correlation coefficient with time elapsed than does the number of molecular apomorphies accrued. This is because there is a three-fold difference in the rate of molecular change amongst the echinoid lineages studied.

@article{smith1992morphological,
    author = "Smith, Andrew B. and Christen, R.",
    title = "Morphological and molecular rates of evolution in post-Paleozoic echinoids",
    year = "1992",
    journal = "The Paleontological Society Special Publications",
    abstract = "Phylogenetic analysis of a data matrix of 86 skeletal characteristics, and of the first 400 bases of the 5’ end of the large subunit ribosomal RNA gene produce congruent cladograms for 11 extant echinoids. Based on these cladistic analyses the great majority of morphologic and molecular apomorphies can be placed in one of 18 independent geological time intervals. When the cladogram is calibrated using the fossil record of post-Paleozoic echinoids, rates of molecular change in 28S rRNA can be calculated and compared with estimated rates of morphological evolution. Morphological and molecular apomorphies acquired in each time interval both correlate moderately strongly with time elapsed, but less strongly with one another. As expected, morphological rates vary considerably over time and between sister groups, but so too do molecular rates. When averaged over all echinoids studied, the number of morphological apomorphies accrued yields a slightly higher Spearman Rank correlation coefficient with time elapsed than does the number of molecular apomorphies accrued. This is because there is a three-fold difference in the rate of molecular change amongst the echinoid lineages studied.",
    url = "https://doi.org/10.1017/s2475262200008339",
    doi = "10.1017/s2475262200008339",
    openalex = "W2783525099",
    pages = "273-273",
    volume = "6"
}

The ever-changing distribution of continents and ocean basins on Earth is fundamental to the environment of the planet. Recent ideas regarding pre-Pangea geography and tectonics offer fresh opportunities to examine possible causative relations between tectonics and environmental and biologic changes during the Neoproterozoic and Paleozoic eras. The starting point is an appreciation that Laurentia, the rift-bounded Precambrian core of North America, could have been juxtaposed with the cratonic cores of some present-day southern continents. This has led to reconstructions of Rodinia and Pannotia, supercontinents that may have existed in early and latest Neoproterozoic time, respectively, before and after the opening of the Pacific Ocean basin. Recognition that the Precordillera of northwest Argentina constitutes a terrane derived from Laurentia may provide critical longitudinal control on the relations of that craton to Gondwana during the Precambrian-Cambrian boundary transition, and in the early Paleozoic. The Precordillera was most likely derived from the general area of the Ouachita embayment, and may have been part of a hypothetical promontory of Laurentia, the “Texas plateau,” which was detached from the Cape of Good Hope embayment within Gondwana between the present-day Falkland-Malvinas Plateau and Transantarctic Mountains margins. Thus the American continents may represent geometric “twins” detached from the Pannotian and Pangean supercontinents in Early Cambrian and Early Cretaceous time, respectively—the new mid-ocean ridge crests of those times initiating the two environmental supercycles of Phanerozoic history 400 m.y. apart. In this scenario, the extremity of the Texas plateau was detached from Laurentia during the Caradocian Epoch, in a rift event ca. 455 Ma that followed Middle Ordovician collision with the proto-Andean margin of Gondwana as part of the complex Indonesian-style Taconic-Famatinian orogeny, which involved several island arc-continent collisions between the two major continental entities. Laurentia then continued its clockwise relative motion around the proto-Andean margin, colliding with other arc terranes, Avalonia, and Baltica en route to the Ouachita-Alleghanian-Hercynian-Uralian collision that completed the amalgamation of Pangea. The important change in single-celled organisms at the Mesoproterozoic-Neoproterozoic boundary (1000 Ma) accompanied assembly of Rodinia along Grenvillian sutures. Possible divergence of metazoan phyla, the appearance and disappearance of the Ediacaran fauna (ca. 650–545 Ma), and the Cambrian “explosion” of skeletalized metazoans (ca. 545–500 Ma) also appear to have taken place within the framework of tectonic change of truly global proportions. These are the opening of the Pacific Ocean basin; uplift and erosion of orogens within the newly assembled Gondwana portion of Pannotia, including a collisional mountain range extending ≈7500 km from Arabia to the Pacific margin of Antarctica; the development of a Pannotia-splitting oceanic spreading ridge system nearly 10 000 km long as Laurentia broke away from Gondwana, Baltica, and Siberia; and initiation of subduction zones along thousands of kilometres of the South American and Antarctic-Australian continental margins. The Middle Ordovician sea-level changes and biologic radiation broadly coincided with initiation of the Appalachian-Andean mountain system along >7000 km of the Taconic and Famatinian belts. These correlations, based on testable paleogeographic reconstructions, invite further speculation about possible causative relations between the internally driven long-term tectonic evolution of the planet, its surface environment, and life.

@article{doi1011300016760619971090016onpgat23co2,
    author = "Dalziel, Ian W. D.",
    title = "OVERVIEW: Neoproterozoic-Paleozoic geography and tectonics: Review, hypothesis, environmental speculation",
    year = "1997",
    journal = "Geological Society of America Bulletin",
    abstract = "The ever-changing distribution of continents and ocean basins on Earth is fundamental to the environment of the planet. Recent ideas regarding pre-Pangea geography and tectonics offer fresh opportunities to examine possible causative relations between tectonics and environmental and biologic changes during the Neoproterozoic and Paleozoic eras. The starting point is an appreciation that Laurentia, the rift-bounded Precambrian core of North America, could have been juxtaposed with the cratonic cores of some present-day southern continents. This has led to reconstructions of Rodinia and Pannotia, supercontinents that may have existed in early and latest Neoproterozoic time, respectively, before and after the opening of the Pacific Ocean basin. Recognition that the Precordillera of northwest Argentina constitutes a terrane derived from Laurentia may provide critical longitudinal control on the relations of that craton to Gondwana during the Precambrian-Cambrian boundary transition, and in the early Paleozoic. The Precordillera was most likely derived from the general area of the Ouachita embayment, and may have been part of a hypothetical promontory of Laurentia, the “Texas plateau,” which was detached from the Cape of Good Hope embayment within Gondwana between the present-day Falkland-Malvinas Plateau and Transantarctic Mountains margins. Thus the American continents may represent geometric “twins” detached from the Pannotian and Pangean supercontinents in Early Cambrian and Early Cretaceous time, respectively—the new mid-ocean ridge crests of those times initiating the two environmental supercycles of Phanerozoic history 400 m.y. apart. In this scenario, the extremity of the Texas plateau was detached from Laurentia during the Caradocian Epoch, in a rift event ca. 455 Ma that followed Middle Ordovician collision with the proto-Andean margin of Gondwana as part of the complex Indonesian-style Taconic-Famatinian orogeny, which involved several island arc-continent collisions between the two major continental entities. Laurentia then continued its clockwise relative motion around the proto-Andean margin, colliding with other arc terranes, Avalonia, and Baltica en route to the Ouachita-Alleghanian-Hercynian-Uralian collision that completed the amalgamation of Pangea. The important change in single-celled organisms at the Mesoproterozoic-Neoproterozoic boundary (1000 Ma) accompanied assembly of Rodinia along Grenvillian sutures. Possible divergence of metazoan phyla, the appearance and disappearance of the Ediacaran fauna (ca. 650–545 Ma), and the Cambrian “explosion” of skeletalized metazoans (ca. 545–500 Ma) also appear to have taken place within the framework of tectonic change of truly global proportions. These are the opening of the Pacific Ocean basin; uplift and erosion of orogens within the newly assembled Gondwana portion of Pannotia, including a collisional mountain range extending ≈7500 km from Arabia to the Pacific margin of Antarctica; the development of a Pannotia-splitting oceanic spreading ridge system nearly 10 000 km long as Laurentia broke away from Gondwana, Baltica, and Siberia; and initiation of subduction zones along thousands of kilometres of the South American and Antarctic-Australian continental margins. The Middle Ordovician sea-level changes and biologic radiation broadly coincided with initiation of the Appalachian-Andean mountain system along >7000 km of the Taconic and Famatinian belts. These correlations, based on testable paleogeographic reconstructions, invite further speculation about possible causative relations between the internally driven long-term tectonic evolution of the planet, its surface environment, and life.",
    url = "https://doi.org/10.1130/0016-7606(1997)109<0016:onpgat>2.3.co;2",
    doi = "10.1130/0016-7606(1997)109<0016:onpgat>2.3.co;2",
    openalex = "W2124559878",
    references = "doi1010160012821x84900177, doi1010160012825296000086, doi101038356673a0, doi101126science25250111409, doi101126science2705236598, doi101126science2735276752, doi10113000167606198394941teomaa20co2, doi1011300091761319880160649iolcmb23co2, doi1011300091761319910190598pmolae23co2, doi1011300091761319950230407scirpo23co2, doi101130dnaggnaf2, doi101146annurevea22050194001535, doi1023073515270, openalexw1549706842, openalexw319663532, openalexw623436458"
}

Paleocene spatangoids are unknown from the Antilles, apart from evidence from trace fossils. The peak of spatangoid diversity was the Eocene. Jamaican Oligo-Miocene spatangoids have a relatively low diversity compared with that of the Antillean region. Plio-Pleistocene spatangoids are poorly known from the Antilles (four genera), in contrast to the Oligo-Miocene (16 genera) and Holocene (17 genera). The depauperate Paleocene and Plio-Pleistocene spatangoid faunas are probably in part artifacts of incomplete sampling, facies-related absences, outcrop area effects and the relative brevity of these stratigraphic intervals.To the large echinoid fauna of the Swanswick Formation (Middle-Upper Eocene) of Jamaica is added the schizasterid Aguayoaster schickleri new species. This is the first record of this genus outside Cuba; it is distinctly more elongate than all other known specimens of this genus. The schizasterid Caribbaster loveni (Cotteau, 1875) is recorded from the Swanswick Formation for the first time, the youngest occurrence of this genus in Jamaica. The coeval Claremont Formation has not previously yielded spatangoid echinoids; the brissid Eupatagus cf. antillarum (Cotteau) from a new locality is the first spatangoid known from a lagoonal unit of the White Limestone Group.

@article{doi1016660022336020000740654sefteo20co2,
    author = "Donovan, Stephen K. and Rowe, Deborah-Ann C.",
    title = "SPATANGOID ECHINOIDS FROM THE EOCENE OF JAMAICA",
    year = "2000",
    journal = "Journal of Paleontology",
    abstract = "Paleocene spatangoids are unknown from the Antilles, apart from evidence from trace fossils. The peak of spatangoid diversity was the Eocene. Jamaican Oligo-Miocene spatangoids have a relatively low diversity compared with that of the Antillean region. Plio-Pleistocene spatangoids are poorly known from the Antilles (four genera), in contrast to the Oligo-Miocene (16 genera) and Holocene (17 genera). The depauperate Paleocene and Plio-Pleistocene spatangoid faunas are probably in part artifacts of incomplete sampling, facies-related absences, outcrop area effects and the relative brevity of these stratigraphic intervals.To the large echinoid fauna of the Swanswick Formation (Middle-Upper Eocene) of Jamaica is added the schizasterid Aguayoaster schickleri new species. This is the first record of this genus outside Cuba; it is distinctly more elongate than all other known specimens of this genus. The schizasterid Caribbaster loveni (Cotteau, 1875) is recorded from the Swanswick Formation for the first time, the youngest occurrence of this genus in Jamaica. The coeval Claremont Formation has not previously yielded spatangoid echinoids; the brissid Eupatagus cf. antillarum (Cotteau) from a new locality is the first spatangoid known from a lagoonal unit of the White Limestone Group.",
    url = "https://doi.org/10.1666/0022-3360(2000)074<0654:sefteo>2.0.co;2",
    doi = "10.1666/0022-3360(2000)074<0654:sefteo>2.0.co;2",
    openalex = "W1966411289",
    references = "doi103133pp321"
}

with Crurithyris planoconvexa brachiopods and fenestellid and encrusting bryozoan epibionts on their spines, occur in a Pennsylvanian (Missourian) echinoderm Lagerstätte in the Winchell Formation of north-central Texas. This occur-rence documents the earliest recorded case of epibionts on echinoids, including usually unpreserved epibionts repeat-edly attached to echinoid hosts. Additionally, this occur-rence provides further insight into deep-time biotic interac-tions between mobile hosts and their attaching organisms. All epibionts are preferentially distributed on the test-proximal ends of the spines. In a contemporaneous sample, no significant size differences are noted between echinoids with and those without epibionts. Epibiont distribution on the spines may occur from one or a combination of causes: antifouling behavior of the echinoid, accidental mechanical removal of epibionts via abrasion, or larval preference in settling. Crurithyris planoconvexa size ranges agree with previous studies of other attached brachiopod size distribu-tions. The echinoid-epibiont association commensal relation-ship appears to have benefited the epibionts by means of as-sociational defense, transportation benefits, increased wa-ter-current and food-gathering possibilities, open habitat for colonization, and decreased competition with other epi-bionts. Conversely, costs for the epibionts would have includ-ed potential mortality from echinoid predators and trans-port into unfavorable environments. For the echinoids in this association, costs, such as increased drag on spines and exposure to epibiont grazers, far outweighed the bene-fits (e.g., potential camouflage effects), although both likely were minimal.

@article{doi1016690883135120030180435hopeeo20co2,
    author = "Schneider, Chris L.",
    title = "Hitchhiking on Pennsylvanian Echinoids: Epibionts on Archaeocidaris",
    year = "2003",
    journal = "Palaios",
    abstract = "with Crurithyris planoconvexa brachiopods and fenestellid and encrusting bryozoan epibionts on their spines, occur in a Pennsylvanian (Missourian) echinoderm Lagerstätte in the Winchell Formation of north-central Texas. This occur-rence documents the earliest recorded case of epibionts on echinoids, including usually unpreserved epibionts repeat-edly attached to echinoid hosts. Additionally, this occur-rence provides further insight into deep-time biotic interac-tions between mobile hosts and their attaching organisms. All epibionts are preferentially distributed on the test-proximal ends of the spines. In a contemporaneous sample, no significant size differences are noted between echinoids with and those without epibionts. Epibiont distribution on the spines may occur from one or a combination of causes: antifouling behavior of the echinoid, accidental mechanical removal of epibionts via abrasion, or larval preference in settling. Crurithyris planoconvexa size ranges agree with previous studies of other attached brachiopod size distribu-tions. The echinoid-epibiont association commensal relation-ship appears to have benefited the epibionts by means of as-sociational defense, transportation benefits, increased wa-ter-current and food-gathering possibilities, open habitat for colonization, and decreased competition with other epi-bionts. Conversely, costs for the epibionts would have includ-ed potential mortality from echinoid predators and trans-port into unfavorable environments. For the echinoids in this association, costs, such as increased drag on spines and exposure to epibiont grazers, far outweighed the bene-fits (e.g., potential camouflage effects), although both likely were minimal.",
    url = "https://doi.org/10.1669/0883-1351(2003)018<0435:hopeeo>2.0.co;2",
    doi = "10.1669/0883-1351(2003)018<0435:hopeeo>2.0.co;2",
    openalex = "W2176084209",
    references = "doi101017s0022336000038932"
}

Fascioles are important early-forming structures that play a key role in allowing irregular echinoids to burrow. They have traditionally been grouped into a small number of types according to their general position on the test, but this masks some significant differences that exist. The precise course that fasciole bands follow over the test plating has been mapped in detail for 89 species of spatangoid echinoids, representing the great majority of fasciole-bearing genera both living and fossil. Within each fasciole type, discrete and conserved patterns can be distinguished, differing both in which plates they are initiated on, and on whether they cross plate growth centres or are late-stage bands positioned towards the edge of the plate. Fasciole position is most highly conserved in the anterior and lateral interambulacral plates and on the earliest forming bands. The existence of different subanal fasciole patterns in the Micrasteridae and Brissidae suggests that these may have evolved independently. Schizasterid and hemiasterine spatangoids can each be subdivided into two major clades, and brissid spatangoids into three clades based on detailed patterns of their fascioles. Plotting fasciole pathways over test architecture provides a rich new source of phylogenetically informative characters.

@article{doi101111j10963642200500161x,
    author = "Smith, Andrew B. and Stockley, Bruce",
    title = "Fasciole pathways in spatangoid echinoids: a new source of phylogenetically informative characters",
    year = "2005",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Fascioles are important early-forming structures that play a key role in allowing irregular echinoids to burrow. They have traditionally been grouped into a small number of types according to their general position on the test, but this masks some significant differences that exist. The precise course that fasciole bands follow over the test plating has been mapped in detail for 89 species of spatangoid echinoids, representing the great majority of fasciole-bearing genera both living and fossil. Within each fasciole type, discrete and conserved patterns can be distinguished, differing both in which plates they are initiated on, and on whether they cross plate growth centres or are late-stage bands positioned towards the edge of the plate. Fasciole position is most highly conserved in the anterior and lateral interambulacral plates and on the earliest forming bands. The existence of different subanal fasciole patterns in the Micrasteridae and Brissidae suggests that these may have evolved independently. Schizasterid and hemiasterine spatangoids can each be subdivided into two major clades, and brissid spatangoids into three clades based on detailed patterns of their fascioles. Plotting fasciole pathways over test architecture provides a rich new source of phylogenetically informative characters.",
    url = "https://doi.org/10.1111/j.1096-3642.2005.00161.x",
    doi = "10.1111/j.1096-3642.2005.00161.x",
    openalex = "W2092028425",
    references = "doi103133pp321"
}

Echinoids are among the most conspicuous and diverse constituents of the Upper Cretaceous and Paleocene marine invertebrate fauna of Argentina. Nine species were collected from localities exposing the Jagüel (Maastrichtian), Roca (Maastrichtian– Danian), Salamanca (Danian), Arroyo Barbudo (Danian), El Fuerte (Danian), and Arroyo Salado (Danian) Formations in northern Patagonia, Argentina. Only one of these taxa, Paraster joannisboehmi (Oppenheim in Böhm, 1903), has been described previously from Argentina. Four taxa, Gauthieria menuthiae (Lambert and Savin in Lambert and Thiéry, 1911), Nucleopygus pullatus (Stoliczka, 1873), Diplodetus nutrix (Lambert in Boule, 1899), and Hemiaster hawkinsi Lambert, 1933, have been described previously from Madagascar. One species, Micropsis desori (Cotteau in Leymerie and Cotteau, 1856), has been described previously from France. One taxon, Pygopistes parrasae is a new species. Argentinian cassiduloids include the only two known Danian species of Nucleopygus and Pygopistes. The spatangoids were not strongly affected by the K-T extinction event. Comparisons of the Patagonian echinoids with those of the Northern Hemisphere indicate that they were strongly influenced by dispersal from Tethyan sources.

@article{doi1016660022336020050791072ucefnp20co2,
    author = "Parma, Sara G. and Casadı́o, Silvio",
    title = "UPPER CRETACEOUS–PALEOCENE ECHINOIDS FROM NORTHERN PATAGONIA, ARGENTINA",
    year = "2005",
    journal = "Journal of Paleontology",
    abstract = "Echinoids are among the most conspicuous and diverse constituents of the Upper Cretaceous and Paleocene marine invertebrate fauna of Argentina. Nine species were collected from localities exposing the Jagüel (Maastrichtian), Roca (Maastrichtian– Danian), Salamanca (Danian), Arroyo Barbudo (Danian), El Fuerte (Danian), and Arroyo Salado (Danian) Formations in northern Patagonia, Argentina. Only one of these taxa, Paraster joannisboehmi (Oppenheim in Böhm, 1903), has been described previously from Argentina. Four taxa, Gauthieria menuthiae (Lambert and Savin in Lambert and Thiéry, 1911), Nucleopygus pullatus (Stoliczka, 1873), Diplodetus nutrix (Lambert in Boule, 1899), and Hemiaster hawkinsi Lambert, 1933, have been described previously from Madagascar. One species, Micropsis desori (Cotteau in Leymerie and Cotteau, 1856), has been described previously from France. One taxon, Pygopistes parrasae is a new species. Argentinian cassiduloids include the only two known Danian species of Nucleopygus and Pygopistes. The spatangoids were not strongly affected by the K-T extinction event. Comparisons of the Patagonian echinoids with those of the Northern Hemisphere indicate that they were strongly influenced by dispersal from Tethyan sources.",
    url = "https://doi.org/10.1666/0022-3360(2005)079[1072:ucefnp]2.0.co;2",
    doi = "10.1666/0022-3360(2005)079[1072:ucefnp]2.0.co;2",
    openalex = "W2174507918",
    references = "doi103133pp321"
}

We present a new three-dimensional theoretical ecospace for the ecological classification of marine animals based on vertical tiering, motility level, and feeding mechanism. In this context, analyses of a database of level-bottom fossil assemblages with abundance counts demonstrate fundamental changes in marine animal ecosystems between the mid-Paleozoic (461–359 Ma) and late Cenozoic (23–0.01 Ma). The average local relative abundance of infaunal burrowers, facultatively motile animals, and predators increased, whereas surface dwellers and completely non-motile animals decreased in abundance. Considering tiering, motility, and feeding together, more modes of life had high to moderate average relative abundance in the Cenozoic than in the Paleozoic. These results are robust to the biasing effects of aragonite dissolution in Paleozoic sediments and to heterogeneities in the latitudinal and environmental distributions of collections. Theoretical ecospace provides a unified system for future analyses of the utilization of ecologic opportunities by marine metazoa.

@article{doi101666060131,
    author = "Bush, Andrew M. and Bambach, Richard K. and Daley, Gwen M.",
    title = "Changes in theoretical ecospace utilization in marine fossil assemblages between the mid-Paleozoic and late Cenozoic",
    year = "2007",
    journal = "Paleobiology",
    abstract = "We present a new three-dimensional theoretical ecospace for the ecological classification of marine animals based on vertical tiering, motility level, and feeding mechanism. In this context, analyses of a database of level-bottom fossil assemblages with abundance counts demonstrate fundamental changes in marine animal ecosystems between the mid-Paleozoic (461–359 Ma) and late Cenozoic (23–0.01 Ma). The average local relative abundance of infaunal burrowers, facultatively motile animals, and predators increased, whereas surface dwellers and completely non-motile animals decreased in abundance. Considering tiering, motility, and feeding together, more modes of life had high to moderate average relative abundance in the Cenozoic than in the Paleozoic. These results are robust to the biasing effects of aragonite dissolution in Paleozoic sediments and to heterogeneities in the latitudinal and environmental distributions of collections. Theoretical ecospace provides a unified system for future analyses of the utilization of ecologic opportunities by marine metazoa.",
    url = "https://doi.org/10.1666/06013.1",
    doi = "10.1666/06013.1",
    openalex = "W2101765162",
    references = "doi1011300091761319980261091afrfoh23co2"
}

Sea levels have been determined for most of the Paleozoic Era (542 to 251 million years ago), but an integrated history of sea levels has remained unrealized. We reconstructed a history of sea-level fluctuations for the entire Paleozoic by using stratigraphic sections from pericratonic and cratonic basins. Evaluation of the timing and amplitude of individual sea-level events reveals that the magnitude of change is the most problematic to estimate accurately. The long-term sea level shows a gradual rise through the Cambrian, reaching a zenith in the Late Ordovician, then a short-lived but prominent withdrawal in response to Hirnantian glaciation. Subsequent but decreasingly substantial eustatic highs occurred in the mid-Silurian, near the Middle/Late Devonian boundary, and in the latest Carboniferous. Eustatic lows are recorded in the early Devonian, near the Mississippian/Pennsylvanian boundary, and in the Late Permian. One hundred and seventy-two eustatic events are documented for the Paleozoic, varying in magnitude from a few tens of meters to approximately 125 meters.

@article{doi101126science1161648,
    author = "Haq, Bilal U. and Schutter, Stephen R.",
    title = "A Chronology of Paleozoic Sea-Level Changes",
    year = "2008",
    journal = "Science",
    abstract = "Sea levels have been determined for most of the Paleozoic Era (542 to 251 million years ago), but an integrated history of sea levels has remained unrealized. We reconstructed a history of sea-level fluctuations for the entire Paleozoic by using stratigraphic sections from pericratonic and cratonic basins. Evaluation of the timing and amplitude of individual sea-level events reveals that the magnitude of change is the most problematic to estimate accurately. The long-term sea level shows a gradual rise through the Cambrian, reaching a zenith in the Late Ordovician, then a short-lived but prominent withdrawal in response to Hirnantian glaciation. Subsequent but decreasingly substantial eustatic highs occurred in the mid-Silurian, near the Middle/Late Devonian boundary, and in the latest Carboniferous. Eustatic lows are recorded in the early Devonian, near the Mississippian/Pennsylvanian boundary, and in the Late Permian. One hundred and seventy-two eustatic events are documented for the Paleozoic, varying in magnitude from a few tens of meters to approximately 125 meters.",
    url = "https://doi.org/10.1126/science.1161648",
    doi = "10.1126/science.1161648",
    openalex = "W1998138507",
    references = "crossref1974the, doi1010079783662011416, doi101016c20090644421, doi101111j13652117200800354x, doi101126science1116412, doi101126science1151540, doi101126science1154339, doi1011300016760619637493sitcio20co2, doi10113000167606198495155cotscf20co2, doi101130001676061985961020mogcag20co2, doi102110jsr2008058, doi102113geoarabia1002127"
}

It has been argued that increases in predation over geological time should result in increases in defensive adaptations in prey taxa. Recent in situ and laboratory observations indicate that cidaroid sea urchins feed on live stalked crinoids, leaving distinct bite marks on their skeletal elements. Similar bite marks on fossil crinoids from Poland strongly suggest that these animals have been subject to echinoid predation since the Triassic. Following their near-demise during the end-Permian extinction, crinoids underwent a major evolutionary radiation during the Middle-Late Triassic that produced distinct morphological and behavioral novelties, particularly motile taxa that contrasted strongly with the predominantly sessile Paleozoic crinoid faunas. We suggest that the appearance and subsequent evolutionary success of motile crinoids were related to benthic predation by post-Paleozoic echinoids with their stronger and more active feeding apparatus and that, in the case of crinoids, the predation-driven Mesozoic marine revolution started earlier than in other groups, perhaps soon after the end-Permian extinction.

@article{doi101073pnas0914199107,
    author = "Baumiller, Tomasz K. and Salamon, Mariusz A. and Gorzelak, Przemysław and Mooi, Rich and Messing, Charles G. and Gahn, Forest J.",
    title = "Post-Paleozoic crinoid radiation in response to benthic predation preceded the Mesozoic marine revolution",
    year = "2010",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "It has been argued that increases in predation over geological time should result in increases in defensive adaptations in prey taxa. Recent in situ and laboratory observations indicate that cidaroid sea urchins feed on live stalked crinoids, leaving distinct bite marks on their skeletal elements. Similar bite marks on fossil crinoids from Poland strongly suggest that these animals have been subject to echinoid predation since the Triassic. Following their near-demise during the end-Permian extinction, crinoids underwent a major evolutionary radiation during the Middle-Late Triassic that produced distinct morphological and behavioral novelties, particularly motile taxa that contrasted strongly with the predominantly sessile Paleozoic crinoid faunas. We suggest that the appearance and subsequent evolutionary success of motile crinoids were related to benthic predation by post-Paleozoic echinoids with their stronger and more active feeding apparatus and that, in the case of crinoids, the predation-driven Mesozoic marine revolution started earlier than in other groups, perhaps soon after the end-Permian extinction.",
    url = "https://doi.org/10.1073/pnas.0914199107",
    doi = "10.1073/pnas.0914199107",
    openalex = "W2064012062",
    references = "doi101017s0022336000061321, doi105281zenodo16046014, kier1974evolutionary"
}

The relationships of post-Palaeozoic echinoids at family level are established through phylogenetic analysis of 169 taxa and 306 skeletal characters (excluding pedicellariae). Previous phylogenetic analyses of echinoids have either examined specific subgroups in detail or have looked at a relatively small number of taxa selected from across the class, with sparse sampling potentially affecting the reliability of results adversely. Our new analyses represent a compromise between encompassing the diversity of form that exists, while keeping the number of taxa to a level that does not make rigorous analysis impossibly time-consuming. In constructing the taxon-character data matrix we have encountered a surprising lack of primary data on plating pattern, lantern, and girdle structure for many supposedly "well-known" taxa. A well-resolved phylogenetic hypothesis was obtained and is used as the basis for a formal classification. Characters generally have a high retention index (>0.7) but low consistency index (<0.25) suggesting that, although characters are largely retained after they first evolve, most also undergo occasional reversal or convergence. Although parts of the resulting trees are only weakly supported (e.g. the precise sister group of the Irregularia), other parts are unambiguously resolved. Not unexpectedly, deep nodes are often not supported by unique apomorphies and higher taxa acquire their characteristic set of features over time. Diagnoses based on crown group taxa thus often fail to encompass fossil stem-group members adequately. Establishing the relationships of taxa at the root of large groups is hampered by limited character resolution. The influence of fossil taxa on the topology was explored by comparing the tree topologies obtained with and without their inclusion. We show that removal of fossils from stem groups makes no difference where their crown group is morphologically conservative, but has a major influence where extant sister groups are separated by large morphological gaps. Completeness of the echinoid record and its match to the stratigraphical record of first occurrences is tested using various metrics and found to be highly congruent, with irregular echinoids showing a higher congruence than regular ones.

@article{doi10108014772011003603556,
    author = "Kroh, Andreas and Smith, Andrew B.",
    title = "The phylogeny and classification of post-Palaeozoic echinoids",
    year = "2010",
    journal = "Journal of Systematic Palaeontology",
    abstract = {The relationships of post-Palaeozoic echinoids at family level are established through phylogenetic analysis of 169 taxa and 306 skeletal characters (excluding pedicellariae). Previous phylogenetic analyses of echinoids have either examined specific subgroups in detail or have looked at a relatively small number of taxa selected from across the class, with sparse sampling potentially affecting the reliability of results adversely. Our new analyses represent a compromise between encompassing the diversity of form that exists, while keeping the number of taxa to a level that does not make rigorous analysis impossibly time-consuming. In constructing the taxon-character data matrix we have encountered a surprising lack of primary data on plating pattern, lantern, and girdle structure for many supposedly "well-known" taxa. A well-resolved phylogenetic hypothesis was obtained and is used as the basis for a formal classification. Characters generally have a high retention index (>0.7) but low consistency index (<0.25) suggesting that, although characters are largely retained after they first evolve, most also undergo occasional reversal or convergence. Although parts of the resulting trees are only weakly supported (e.g. the precise sister group of the Irregularia), other parts are unambiguously resolved. Not unexpectedly, deep nodes are often not supported by unique apomorphies and higher taxa acquire their characteristic set of features over time. Diagnoses based on crown group taxa thus often fail to encompass fossil stem-group members adequately. Establishing the relationships of taxa at the root of large groups is hampered by limited character resolution. The influence of fossil taxa on the topology was explored by comparing the tree topologies obtained with and without their inclusion. We show that removal of fossils from stem groups makes no difference where their crown group is morphologically conservative, but has a major influence where extant sister groups are separated by large morphological gaps. Completeness of the echinoid record and its match to the stratigraphical record of first occurrences is tested using various metrics and found to be highly congruent, with irregular echinoids showing a higher congruence than regular ones.},
    url = "https://doi.org/10.1080/14772011003603556",
    doi = "10.1080/14772011003603556",
    openalex = "W2072979411",
    references = "doi1010160031018268900989, doi101017s0022336000061321, doi101017s0094837300005248, doi101038019118a0, doi101038114085a0, doi10108010635150290102339, doi101093nqs5vi146318i, doi101111j00310239200400364x, doi101111j109600311999tb00277x, doi101111j10960031200800209x, doi101111j14636409200500201x, doi101111j146979981833tb06418x, doi101126science972526482b, doi103133pp321, doi105281zenodo16046014, doi105962bhltitle126954, doi105962bhltitle156765, doi105962bhltitle542, kier1974evolutionary, openalexw2894525608, openalexw635257420"
}

This study focuses on sclerobionts from a large collection of epibenthic echinoids ([2,000 specimens) of the genera Conulus and Camerogalerus. Samples were collected from five localities in southern Poland (Polish Jura and Miecho w Trough), where Turonian carbonates with terrigenous input are exposed. Low intensity (mean ca. 5 %, maximum ca. 10 %) and slight encrustation (''loosening effect'') exclusively by episkeletozoans probably resulted from low productivity of encrusters while the importance of other factors cannot be excluded unambiguously. Echinoids served as a main substratum and after death formed shellgrounds ('echinoid carpet') offering abundant benthic islands for encrusters in an otherwise soft-bottom environment. The moderate abundance but low-diversity assemblage is represented by bivalves, sedentary polychaetes, foraminifera, bryozoans, corals, and sponges. This assemblage is similar to a nearly contemporaneous assemblage from the Bohemian Basin. The presence of numerous spirorbins offers insights into their early evolution and may indicate that their first peak in abundance after origination was not prior to the earliest Turonian. This is regarded as one of the important ecological steps towards the rise of modern sclerobiont communities. Encruster diversities are independent of their abundance and, as shown in our novel planar projections, lateral parts of tests were preferentially encrusted. This pattern is explained by the combination of largest flat area and stable orientation. Encrusting bivalves and serpulids dominated hard substrate environments in the Turonian of Poland.

@article{doi101007s103470120319z,
    author = "Borszcz, Tomasz and Kukliński, Piotr and Zatoń, Michał",
    title = "Encrustation patterns on Late Cretaceous (Turonian) echinoids from southern Poland",
    year = "2012",
    journal = "Facies",
    abstract = "This study focuses on sclerobionts from a large collection of epibenthic echinoids ([2,000 specimens) of the genera Conulus and Camerogalerus. Samples were collected from five localities in southern Poland (Polish Jura and Miecho w Trough), where Turonian carbonates with terrigenous input are exposed. Low intensity (mean ca. 5 \%, maximum ca. 10 \%) and slight encrustation (''loosening effect'') exclusively by episkeletozoans probably resulted from low productivity of encrusters while the importance of other factors cannot be excluded unambiguously. Echinoids served as a main substratum and after death formed shellgrounds ('echinoid carpet') offering abundant benthic islands for encrusters in an otherwise soft-bottom environment. The moderate abundance but low-diversity assemblage is represented by bivalves, sedentary polychaetes, foraminifera, bryozoans, corals, and sponges. This assemblage is similar to a nearly contemporaneous assemblage from the Bohemian Basin. The presence of numerous spirorbins offers insights into their early evolution and may indicate that their first peak in abundance after origination was not prior to the earliest Turonian. This is regarded as one of the important ecological steps towards the rise of modern sclerobiont communities. Encruster diversities are independent of their abundance and, as shown in our novel planar projections, lateral parts of tests were preferentially encrusted. This pattern is explained by the combination of largest flat area and stable orientation. Encrusting bivalves and serpulids dominated hard substrate environments in the Turonian of Poland.",
    url = "https://doi.org/10.1007/s10347-012-0319-z",
    doi = "10.1007/s10347-012-0319-z",
    openalex = "W2092983022",
    references = "doi101016s0012825202001319, doi101073pnas0404300101, doi10108014772011003603556, doi1023071936969, doi1023071942223, doi1023071942484, doi1023073514686, doi103354meps058175, doi105860choice284524, openalexw2183707334"
}

Sea anemones of the genus Aiptasia Gosse, 1858 are conspicuous members of shallow-water environments worldwide and serve as a model system for studies of cnidarian-dinoflagellate symbiosis. However, to date there have been no comprehensive analyses investigating the systematics of the group. In addition, previously published phylogenetic studies of sea anemones have shown that the genus is not monophyletic. Herein we revise the genus Aiptasia and the family Aiptasiidae Carlgren, 1924 using newly-collected material. We find that the formerly-named A. pallida (Agassiz in Verrill, 1864) (now Exaiptasia pallida comb. nov.) encompasses a single, widespread species from the tropics and subtropics; we erect a new genus, Exaiptasia gen. nov., for this species primarily based on cnidae, mode of asexual reproduction and symbionts. We also find morphological evidence that supports splitting A. mutabilis into two species: A. couchii (Cocks, 1851) and A. mutabilis. In addition, we find Bellactis Dube, 1983 (formerly placed within Sagartiidae Gosse, 1858) and Laviactis gen. nov. (formerly known Ragactis Andres, 1883, whose familial placement was previously uncertain) belonging within Aiptasiidae. Aiptasiidae is a morphologically homogeneous family whose members (those species in genera Aiptasia, Aiptasiogeton Schmidt, 1972, Bartholomea Duchassaing de Fombressin & Michelotti, 1864, Bellactis, Exaiptasia gen. nov., and Laviactis gen. nov.) are characterized by ectodermal longitudinal muscles in the distal column, rows of cinclides in mid-column, microbasic b-mastigophores in the column, and acontia with basitrichs and microbasic p-amastigophores.

@article{doi1011646zootaxa382612,
    author = "Grajales, Alejandro and Rodríguez, Estefanía",
    title = "Morphological revision of the genus Aiptasia and the family Aiptasiidae (Cnidaria, Actiniaria, Metridioidea)",
    year = "2014",
    journal = "Zootaxa",
    abstract = "Sea anemones of the genus Aiptasia Gosse, 1858 are conspicuous members of shallow-water environments worldwide and serve as a model system for studies of cnidarian-dinoflagellate symbiosis. However, to date there have been no comprehensive analyses investigating the systematics of the group. In addition, previously published phylogenetic studies of sea anemones have shown that the genus is not monophyletic. Herein we revise the genus Aiptasia and the family Aiptasiidae Carlgren, 1924 using newly-collected material. We find that the formerly-named A. pallida (Agassiz in Verrill, 1864) (now Exaiptasia pallida comb. nov.) encompasses a single, widespread species from the tropics and subtropics; we erect a new genus, Exaiptasia gen. nov., for this species primarily based on cnidae, mode of asexual reproduction and symbionts. We also find morphological evidence that supports splitting A. mutabilis into two species: A. couchii (Cocks, 1851) and A. mutabilis. In addition, we find Bellactis Dube, 1983 (formerly placed within Sagartiidae Gosse, 1858) and Laviactis gen. nov. (formerly known Ragactis Andres, 1883, whose familial placement was previously uncertain) belonging within Aiptasiidae. Aiptasiidae is a morphologically homogeneous family whose members (those species in genera Aiptasia, Aiptasiogeton Schmidt, 1972, Bartholomea Duchassaing de Fombressin \& Michelotti, 1864, Bellactis, Exaiptasia gen. nov., and Laviactis gen. nov.) are characterized by ectodermal longitudinal muscles in the distal column, rows of cinclides in mid-column, microbasic b-mastigophores in the column, and acontia with basitrichs and microbasic p-amastigophores.",
    url = "https://doi.org/10.11646/zootaxa.3826.1.2",
    doi = "10.11646/zootaxa.3826.1.2",
    openalex = "W1996923774",
    references = "doi105962bhltitle40014"
}

How ecological and morphological diversity accrues over geological time has been much debated by paleobiologists. Evidence from the fossil record suggests that many clades reach maximal diversity early in their evolutionary history, followed by a decline in evolutionary rates as ecological space fills or due to internal constraints. Here, we apply recently developed methods for estimating rates of morphological evolution during the post-Paleozoic history of a major invertebrate clade, the Echinoidea. Contrary to expectation, rates of evolution were lowest during the initial phase of diversification following the Permo-Triassic mass extinction and increased over time. Furthermore, although several subclades show high initial rates and net decreases in rates of evolution, consistent with "early bursts" of morphological diversification, at more inclusive taxonomic levels, these bursts appear as episodic peaks. Peak rates coincided with major shifts in ecological morphology, primarily associated with innovations in feeding strategies. Despite having similar numbers of species in today's oceans, regular echinoids have accrued far less morphological diversity than irregular echinoids due to lower intrinsic rates of morphological evolution and less morphological innovation, the latter indicative of constrained or bounded evolution. These results indicate that rates of evolution are extremely heterogenous through time and their interpretation depends on the temporal and taxonomic scale of analysis.

@article{doi101073pnas1418153112,
    author = "Hopkins, Melanie J. and Smith, Andrew B.",
    title = "Dynamic evolutionary change in post-Paleozoic echinoids and the importance of scale when interpreting changes in rates of evolution",
    year = "2015",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {How ecological and morphological diversity accrues over geological time has been much debated by paleobiologists. Evidence from the fossil record suggests that many clades reach maximal diversity early in their evolutionary history, followed by a decline in evolutionary rates as ecological space fills or due to internal constraints. Here, we apply recently developed methods for estimating rates of morphological evolution during the post-Paleozoic history of a major invertebrate clade, the Echinoidea. Contrary to expectation, rates of evolution were lowest during the initial phase of diversification following the Permo-Triassic mass extinction and increased over time. Furthermore, although several subclades show high initial rates and net decreases in rates of evolution, consistent with "early bursts" of morphological diversification, at more inclusive taxonomic levels, these bursts appear as episodic peaks. Peak rates coincided with major shifts in ecological morphology, primarily associated with innovations in feeding strategies. Despite having similar numbers of species in today's oceans, regular echinoids have accrued far less morphological diversity than irregular echinoids due to lower intrinsic rates of morphological evolution and less morphological innovation, the latter indicative of constrained or bounded evolution. These results indicate that rates of evolution are extremely heterogenous through time and their interpretation depends on the temporal and taxonomic scale of analysis.},
    url = "https://doi.org/10.1073/pnas.1418153112",
    doi = "10.1073/pnas.1418153112",
    openalex = "W2068132819",
    references = "doi10108014772011003603556, doi1016660094837320000260056cefisg20co2"
}

Two species of spatangoid echinoid belonging to Heteraster Orbigny, 1853, are described from Lower Cretaceous deposits (Gadvan and Dariyan formations) at the Kuh-e Gadvan and Banesh sections situated in Zagros Mountains, south of Iran. Heteraster couloni (Agassiz, 1839) is confirmed in the Barremian and Heteraster delgadoi (Loriol, 1884) in the late Aptian-Albian of Iran. The occurrences of Heteraster and other spatangoid echinoids in Iran show a clear distinction between assemblages from the southern and northern margins of the Tethys during the Early Cretaceous.

@article{doi104267204261883,
    author = "Yavari, Mazaher and Yazdi, Mehdi and Gahalavand, Hormoz and Shadan, Hossein Kamyabi and Adabi, Mohammad Hossein and Villier, Loïc",
    title = "Early Cretaceous Toxasterid Echinoid Heteraster from the high Zagros basin, south of Iran",
    year = "2016",
    journal = "Carnets de géologie (Notebooks on geology)",
    abstract = "Two species of spatangoid echinoid belonging to Heteraster Orbigny, 1853, are described from Lower Cretaceous deposits (Gadvan and Dariyan formations) at the Kuh-e Gadvan and Banesh sections situated in Zagros Mountains, south of Iran. Heteraster couloni (Agassiz, 1839) is confirmed in the Barremian and Heteraster delgadoi (Loriol, 1884) in the late Aptian-Albian of Iran. The occurrences of Heteraster and other spatangoid echinoids in Iran show a clear distinction between assemblages from the southern and northern margins of the Tethys during the Early Cretaceous.",
    url = "https://doi.org/10.4267/2042/61883",
    doi = "10.4267/2042/61883",
    openalex = "W2576141137"
}

Vicariant events have been widely used to calibrate rates of molecular evolution, the completion of the Central American Isthmus more extensively than any other. Recent studies have claimed that rather than the generally accepted date of ~3 million years ago (Ma), the Isthmus was effectively complete by the middle Miocene, 13 Ma. We present a fossil calibrated phylogeny of the new world sand dollar genus Encope, based on one nuclear and four mitochondrial genes, calibrated with fossils at multiple nodes. Present day distributions of Encope are likely the result of multiple range contractions and extinction events. Most species are now endemic to a single region, but one widely distributed species in each ocean is composed of morphotypes previously described as separate species. The most recent separation between eastern Pacific and Caribbean extant clades occurred at 4.90 Ma, indicating that the Isthmus of Panama allowed genetic exchange until the Pliocene. The rate of evolution of mitochondrial genes in Encope has been ten times slower than in the closely related genera Mellita and Lanthonia. This large difference in rates suggests that splits between eastern Pacific and Caribbean biota, dated on the assumption of a "universal" mitochondrial DNA clock are not valid.

@article{doi101038s4159801711875w,
    author = "Coppard, Simon E. and Lessios, H. A.",
    title = "Phylogeography of the sand dollar genus Encope: implications regarding the Central American Isthmus and rates of molecular evolution",
    year = "2017",
    journal = "Scientific Reports",
    abstract = {Vicariant events have been widely used to calibrate rates of molecular evolution, the completion of the Central American Isthmus more extensively than any other. Recent studies have claimed that rather than the generally accepted date of \textasciitilde 3 million years ago (Ma), the Isthmus was effectively complete by the middle Miocene, 13 Ma. We present a fossil calibrated phylogeny of the new world sand dollar genus Encope, based on one nuclear and four mitochondrial genes, calibrated with fossils at multiple nodes. Present day distributions of Encope are likely the result of multiple range contractions and extinction events. Most species are now endemic to a single region, but one widely distributed species in each ocean is composed of morphotypes previously described as separate species. The most recent separation between eastern Pacific and Caribbean extant clades occurred at 4.90 Ma, indicating that the Isthmus of Panama allowed genetic exchange until the Pliocene. The rate of evolution of mitochondrial genes in Encope has been ten times slower than in the closely related genera Mellita and Lanthonia. This large difference in rates suggests that splits between eastern Pacific and Caribbean biota, dated on the assumption of a "universal" mitochondrial DNA clock are not valid.},
    url = "https://doi.org/10.1038/s41598-017-11875-w",
    doi = "10.1038/s41598-017-11875-w",
    openalex = "W2755176703",
    references = "doi103133pp321"
}

BACKGROUND: In Metazoa, mitochondrial markers are the most commonly used targets for inferring species-level molecular phylogenies due to their extremely low rate of recombination, maternal inheritance, ease of use and fast substitution rate in comparison to nuclear DNA. The mitochondrial control region (CR) is the main non-coding area of the mitochondrial genome and contains the mitochondrial origin of replication and transcription. While sequences of the cytochrome oxidase subunit 1 (COI) and 16S rRNA genes are the prime mitochondrial markers in phylogenetic studies, the highly variable CR is typically ignored and not targeted in such analyses. However, the higher substitution rate of the CR can be harnessed to infer the phylogeny of closely related species, and the use of a non-coding region alleviates biases resulting from both directional and purifying selection. Additionally, complete mitochondrial genome assemblies utilizing next generation sequencing (NGS) data often show exceptionally low coverage at specific regions, including the CR. This can only be resolved by targeted sequencing of this region. RESULTS: Here we provide novel sequence data for the echinoid mitochondrial control region in over 40 species across the echinoid phylogenetic tree. We demonstrate the advantages of directly targeting the CR and adjacent tRNAs to facilitate complementing low coverage NGS data from complete mitochondrial genome assemblies. Finally, we test the performance of this region as a phylogenetic marker both in the lab and in phylogenetic analyses, and demonstrate its superior performance over the other available mitochondrial markers in echinoids. CONCLUSIONS: Our target region of the mitochondrial CR (1) facilitates the first thorough investigation of this region across a wide range of echinoid taxa, (2) provides a tool for complementing missing data in NGS experiments, and (3) identifies the CR as a powerful, novel marker for phylogenetic inference in echinoids due to its high variability, lack of selection, and high compatibility across the entire class, outperforming conventional mitochondrial markers.

@article{doi101186s128620181198x,
    author = "Bronstein, Omri and Kroh, Andreas and Haring, Elisabeth",
    title = "Mind the gap! The mitochondrial control region and its power as a phylogenetic marker in echinoids",
    year = "2018",
    journal = "BMC Evolutionary Biology",
    abstract = "BACKGROUND: In Metazoa, mitochondrial markers are the most commonly used targets for inferring species-level molecular phylogenies due to their extremely low rate of recombination, maternal inheritance, ease of use and fast substitution rate in comparison to nuclear DNA. The mitochondrial control region (CR) is the main non-coding area of the mitochondrial genome and contains the mitochondrial origin of replication and transcription. While sequences of the cytochrome oxidase subunit 1 (COI) and 16S rRNA genes are the prime mitochondrial markers in phylogenetic studies, the highly variable CR is typically ignored and not targeted in such analyses. However, the higher substitution rate of the CR can be harnessed to infer the phylogeny of closely related species, and the use of a non-coding region alleviates biases resulting from both directional and purifying selection. Additionally, complete mitochondrial genome assemblies utilizing next generation sequencing (NGS) data often show exceptionally low coverage at specific regions, including the CR. This can only be resolved by targeted sequencing of this region. RESULTS: Here we provide novel sequence data for the echinoid mitochondrial control region in over 40 species across the echinoid phylogenetic tree. We demonstrate the advantages of directly targeting the CR and adjacent tRNAs to facilitate complementing low coverage NGS data from complete mitochondrial genome assemblies. Finally, we test the performance of this region as a phylogenetic marker both in the lab and in phylogenetic analyses, and demonstrate its superior performance over the other available mitochondrial markers in echinoids. CONCLUSIONS: Our target region of the mitochondrial CR (1) facilitates the first thorough investigation of this region across a wide range of echinoid taxa, (2) provides a tool for complementing missing data in NGS experiments, and (3) identifies the CR as a powerful, novel marker for phylogenetic inference in echinoids due to its high variability, lack of selection, and high compatibility across the entire class, outperforming conventional mitochondrial markers.",
    url = "https://doi.org/10.1186/s12862-018-1198-x",
    doi = "10.1186/s12862-018-1198-x",
    openalex = "W2805094274",
    references = "doi10108014772011003603556, doi105281zenodo16046014"
}

Abstract A rich echinoid fauna within the middle Miocene carbonate sedimentary succession cropping out along the coast between Santa Caterina di Pittinuri and S'Archittu (central-western Sardinia) allows the comparison of faunal gradients and preservation potentials from both hard and soft substrata. Three echinoid assemblages are recognized. Faunal composition, as well as taphonomic and sedimentological features and functional morphological interpretation of the echinoid test indicate an outer sublittoral setting. Assemblage 1 represents a highly structured environment within the photic zone, with mobile substrata occupied by infaunal irregular echinoids, mainly spatangoids, and localized hard substrata, provided by rhodolith beds, with epibenthic regular echinoids represented by the co-occurrence of the diadematid Diadema Gray, 1825 and the toxopneustids Tripneustes L. Agassiz, 1841 and Schizechinus Pomel, 1869. Assemblage 2 shows a higher diversity of irregular echinoids, dominated by the clypeasteroids Echinocyamus van Phelsum, 1774 and Clypeaster Lamarck, 1801 and different spatangoids, with the minute trigonocidarid Genocidaris A. Agassiz, 1869 among regular echinoids. This assemblage points to a soft-bottom environment with moderate water-energy conditions, periodically affected by storms. A low-diversity echinoid fauna in Assemblage 3, dominated by the spatangoids Brissopsis L. Agassiz, 1840 and Ova Gray, 1825, documents a deeper, soft-bottom environment, possibly below storm-wave base. These results indicate that the diversity of echinoid faunas originating in sublittoral environments is related to: (1) the presence of both soft and hard substrata, (2) differential preservation potentials of the various echinoid taxa, (3) intense bioturbation, and (4) sediment deposition by sporadic storm events.

@article{doi101017jpa20194,
    author = "Mancosu, Andrea and Nebelsick, James H.",
    title = "Paleoecology of sublittoral Miocene echinoids from Sardinia: A case study for substrate controls of faunal distributions",
    year = "2019",
    journal = "Journal of Paleontology",
    abstract = "Abstract A rich echinoid fauna within the middle Miocene carbonate sedimentary succession cropping out along the coast between Santa Caterina di Pittinuri and S'Archittu (central-western Sardinia) allows the comparison of faunal gradients and preservation potentials from both hard and soft substrata. Three echinoid assemblages are recognized. Faunal composition, as well as taphonomic and sedimentological features and functional morphological interpretation of the echinoid test indicate an outer sublittoral setting. Assemblage 1 represents a highly structured environment within the photic zone, with mobile substrata occupied by infaunal irregular echinoids, mainly spatangoids, and localized hard substrata, provided by rhodolith beds, with epibenthic regular echinoids represented by the co-occurrence of the diadematid Diadema Gray, 1825 and the toxopneustids Tripneustes L. Agassiz, 1841 and Schizechinus Pomel, 1869. Assemblage 2 shows a higher diversity of irregular echinoids, dominated by the clypeasteroids Echinocyamus van Phelsum, 1774 and Clypeaster Lamarck, 1801 and different spatangoids, with the minute trigonocidarid Genocidaris A. Agassiz, 1869 among regular echinoids. This assemblage points to a soft-bottom environment with moderate water-energy conditions, periodically affected by storms. A low-diversity echinoid fauna in Assemblage 3, dominated by the spatangoids Brissopsis L. Agassiz, 1840 and Ova Gray, 1825, documents a deeper, soft-bottom environment, possibly below storm-wave base. These results indicate that the diversity of echinoid faunas originating in sublittoral environments is related to: (1) the presence of both soft and hard substrata, (2) differential preservation potentials of the various echinoid taxa, (3) intense bioturbation, and (4) sediment deposition by sporadic storm events.",
    url = "https://doi.org/10.1017/jpa.2019.4",
    doi = "10.1017/jpa.2019.4",
    openalex = "W2936371423",
    references = "doi101016jpalaeo201603024"
}

Geographic range is an important macroevolutionary parameter frequently considered in paleontological studies as species' distributions and range sizes are determined by a variety of biotic and abiotic factors well known to affect the differential birth and death of species. Thus, considering how distributions and range sizes fluctuate over time can provide important insight into evolutionary dynamics. This study uses Geographic Information Systems (GIS) and analyses of evolutionary rates to examine how in some species within the Cephalopoda, an important pelagic clade, geographic range size and rates of speciation and extinction changed throughout the Pennsylvanian and early Permian in the North American Midcontinent Sea. This period is particularly interesting for biogeographic and evolutionary studies because it is characterized by repetitive interglacial-glacial cycles, a global transition from an icehouse to a greenhouse climate during the Late Paleozoic Ice Age, and decelerated macroevolutionary dynamics, i.e. low speciation and extinction rates. The analyses presented herein indicate that cephalopod species diversity was not completely static and actually fluctuated throughout the Pennsylvanian and early Permian, matching findings from other studies. However, contrary to some other studies, the mean geographic ranges of cephalopod species did not change significantly through time, despite numerous climate oscillations; further, geographic range size did not correlate with rates of speciation and extinction. These results suggest that pelagic organisms may have responded differently to late Paleozoic climate changes than benthic organisms, although additional consideration of this issue is needed. Finally, these results indicate that, at least in the case of cephalopods, macroevolution during the late Paleozoic was more dynamic than previously characterized, and patterns may have varied across different clades during this interval.

@article{doi107717peerj6910,
    author = "Kolis, Kayla and Lieberman, Bruce S.",
    title = "Using GIS to examine biogeographic and macroevolutionary patterns in some late Paleozoic cephalopods from the North American Midcontinent Sea",
    year = "2019",
    journal = "PeerJ",
    abstract = "Geographic range is an important macroevolutionary parameter frequently considered in paleontological studies as species' distributions and range sizes are determined by a variety of biotic and abiotic factors well known to affect the differential birth and death of species. Thus, considering how distributions and range sizes fluctuate over time can provide important insight into evolutionary dynamics. This study uses Geographic Information Systems (GIS) and analyses of evolutionary rates to examine how in some species within the Cephalopoda, an important pelagic clade, geographic range size and rates of speciation and extinction changed throughout the Pennsylvanian and early Permian in the North American Midcontinent Sea. This period is particularly interesting for biogeographic and evolutionary studies because it is characterized by repetitive interglacial-glacial cycles, a global transition from an icehouse to a greenhouse climate during the Late Paleozoic Ice Age, and decelerated macroevolutionary dynamics, i.e. low speciation and extinction rates. The analyses presented herein indicate that cephalopod species diversity was not completely static and actually fluctuated throughout the Pennsylvanian and early Permian, matching findings from other studies. However, contrary to some other studies, the mean geographic ranges of cephalopod species did not change significantly through time, despite numerous climate oscillations; further, geographic range size did not correlate with rates of speciation and extinction. These results suggest that pelagic organisms may have responded differently to late Paleozoic climate changes than benthic organisms, although additional consideration of this issue is needed. Finally, these results indicate that, at least in the case of cephalopods, macroevolution during the late Paleozoic was more dynamic than previously characterized, and patterns may have varied across different clades during this interval.",
    url = "https://doi.org/10.7717/peerj.6910",
    doi = "10.7717/peerj.6910",
    openalex = "W2944739164"
}

@inproceedings{andlapic2020an,
    author = "Lapic, Whitney and Petsios, Elizabeth and Tennakoon, Shamindri and Portell, Roger W. and Kowalewski, Michal and Tyler, Carrie L.",
    title = "AN ASYNCHRONOUS MESOZOIC MARINE REVOLUTION: DRILLING VERSUS DUROPHAGY IN POST-PALEOZOIC ECHINOIDS",
    year = "2020",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2020am-356327",
    doi = "10.1130/abs/2020am-356327",
    openalex = "W3096247109"
}

Abstract Members of the echinoid order Spatangoida, a highly diverse and abundant marine invertebrate clade, were important denizens of the Cretaceous Western Interior Seaway (WIS), an epicontinental seaway that divided North America in two during an interval of greenhouse conditions between roughly 100 and 65 million years ago. A phylogenetic analysis of spatangoids was conducted using a character matrix of 32 characters from 21 species. Species that occur in the WIS were considered comprehensively, and species from other regions such as South America, Europe, and North Africa were also incorporated into the analysis. Phylogenetic patterns retrieved are largely congruent with preexisting family-level classifications; however, species within several genera, especially Hemiaster and Heteraster, need to be reassigned so that classification better reflects phylogeny. The genera Washitaster and Heteraster are closely related, as are Mecaster, Palhemiaster, and Proraster; Pliotoxaster, Macraster, and Hemiaster; and Micraster and Diplodetus. Biogeographic patterns were also considered using the phylogeny, and several episodes of vicariance and range expansion were identified. These were possibly related to some of the various major episodes of sea-level rise and fall during the Cretaceous. In particular, Valangian–mid-Aptian regressions may have caused vicariance within Heteraster and Washitaster while other early spatangoid vicariance may be related to regressions during the late Aptian–early Cenomanian. Further, vicariance caused by regressions during the mid-Cenomanian–Maastrichtian may have driven diversification within Micraster and Diplodetus. Last, transgressions during the late Aptian–early Cenomanian seem to have spurred prominent range expansions in Mecaster and Hemiaster.

@article{doi101017jpa2020102,
    author = "Byrum, Steven and Lieberman, Bruce S.",
    title = "Phylogeny and biogeography of some Cretaceous spatangoid echinoids with special emphasis on taxa from the Western Interior Seaway",
    year = "2020",
    journal = "Journal of Paleontology",
    abstract = "Abstract Members of the echinoid order Spatangoida, a highly diverse and abundant marine invertebrate clade, were important denizens of the Cretaceous Western Interior Seaway (WIS), an epicontinental seaway that divided North America in two during an interval of greenhouse conditions between roughly 100 and 65 million years ago. A phylogenetic analysis of spatangoids was conducted using a character matrix of 32 characters from 21 species. Species that occur in the WIS were considered comprehensively, and species from other regions such as South America, Europe, and North Africa were also incorporated into the analysis. Phylogenetic patterns retrieved are largely congruent with preexisting family-level classifications; however, species within several genera, especially Hemiaster and Heteraster, need to be reassigned so that classification better reflects phylogeny. The genera Washitaster and Heteraster are closely related, as are Mecaster, Palhemiaster, and Proraster; Pliotoxaster, Macraster, and Hemiaster; and Micraster and Diplodetus. Biogeographic patterns were also considered using the phylogeny, and several episodes of vicariance and range expansion were identified. These were possibly related to some of the various major episodes of sea-level rise and fall during the Cretaceous. In particular, Valangian–mid-Aptian regressions may have caused vicariance within Heteraster and Washitaster while other early spatangoid vicariance may be related to regressions during the late Aptian–early Cenomanian. Further, vicariance caused by regressions during the mid-Cenomanian–Maastrichtian may have driven diversification within Micraster and Diplodetus. Last, transgressions during the late Aptian–early Cenomanian seem to have spurred prominent range expansions in Mecaster and Hemiaster.",
    url = "https://doi.org/10.1017/jpa.2020.102",
    doi = "10.1017/jpa.2020.102",
    openalex = "W3112581246",
    references = "arachchige2019taxonomy, doi101016002555648290027x, doi101016jgloplacha201312007, doi101017jpa201879, doi10108014772011003603556, doi101111j109600311994tb00179x, doi101144gslsp19880370119, doi101306m56578, doi1023073515270, doi105962bhltitle40014, openalexw3217097258, openalexw592572837"
}

The study of echinoid evolution, diversity, and ecology has always suffered from the fact that they are represented by taxa showing widely differing architectural designs of their multi-plated skeletons, inhabiting a large range of marine paleoenvironments, which result in highly varying taphonomic biases dictating their presence and recognition. This Element addresses the taphonomy of echinoids and includes: a general introduction to the morphological features of echinoids that play a role in their preservation; a review of processes which play an important role in the differential preservation of both regular and irregular echinoids including predation and transport; a summary of taphonomic pathways included in actualistic studies for recent sea urchins and then reconstructed for fossil taxa; and finally, a case study of the variation of echinoid taphonomy across a shelf gradient using the rich Miocene echinoid fauna of Sardinia.

@book{doi1010179781108893411,
    author = "Nebelsick, James H. and Mancosu, Andrea",
    title = "The Taphonomy of Echinoids",
    year = "2021",
    booktitle = "Cambridge University Press eBooks",
    abstract = "The study of echinoid evolution, diversity, and ecology has always suffered from the fact that they are represented by taxa showing widely differing architectural designs of their multi-plated skeletons, inhabiting a large range of marine paleoenvironments, which result in highly varying taphonomic biases dictating their presence and recognition. This Element addresses the taphonomy of echinoids and includes: a general introduction to the morphological features of echinoids that play a role in their preservation; a review of processes which play an important role in the differential preservation of both regular and irregular echinoids including predation and transport; a summary of taphonomic pathways included in actualistic studies for recent sea urchins and then reconstructed for fossil taxa; and finally, a case study of the variation of echinoid taphonomy across a shelf gradient using the rich Miocene echinoid fauna of Sardinia.",
    url = "https://doi.org/10.1017/9781108893411",
    doi = "10.1017/9781108893411",
    openalex = "W4200095737",
    references = "doi1010079783540775980, doi101007bf00379188, doi101007s103470120319z, doi101016jpalaeo200909010, doi101016jpalaeo201603024, doi1010179781009049016, doi1010179781108893411, doi101017jpa2016146, doi101017s0094837300005248, doi1012019781003077831, doi1016690883135120020170522antfmo20co2, doi1023071938786, doi103354meps140071, doi105860choice295709, openalexw1567448602, openalexw574363047"
}

Abstract Predation is of great importance in understanding the diversification of spatangoid echinoids as well as their preservation in the fossil record. Herein, the spatangoid-dominated Miocene carbonate succession of Punta Foghe (Montiferru area, central-western Sardinia, Italy) is studied with the aim of reconstructing paleoenvironmental conditions and investigating abiotic and biotic factors, including predation, that influence the paleoecology and preservation potential of spatangoid echinoids. The echinoid fauna is dominated by the spatangoid Agassizia and, to a lesser extent, the clypeasteroid Clypeaster. The fauna also includes both regular (undetermined diadematoids and camarodonts) and irregular (Plagiobrissus, Echinocyamus, and Koehleraster) forms. Echinoids and associated fossil content, along with taphonomic and sedimentological signatures, indicate an inner sublittoral environment with moderate energy conditions affected by high-energy events. Agassizia remains, which consist mainly of complete and well-preserved tests, commonly bear subcircular drill holes that are interpreted as the result of cassid gastropod predation and investigated with respect to size selectivity and stereotypy of attack sites. Potential biases related to drilling predation and biostratinomy on the preservation potential of spatangoid tests are discussed. Agassizia lacks any morphological adaptation to minimize high predation risk, including defensive spines and the ability to burrow deeply into the sediment. An antipredator behavior possibly relied on a gregarious life-history strategy, reducing the frequency of attacks on specific individuals by cassid predators.

@article{doi101017jpa202228,
    author = "Mancosu, Andrea and Nebelsick, James H. and Buosi, Carla",
    title = "Drilling predation on spatangoid echinoids from the Miocene of Sardinia: a taphonomic and paleoecological perspective",
    year = "2022",
    journal = "Journal of Paleontology",
    abstract = "Abstract Predation is of great importance in understanding the diversification of spatangoid echinoids as well as their preservation in the fossil record. Herein, the spatangoid-dominated Miocene carbonate succession of Punta Foghe (Montiferru area, central-western Sardinia, Italy) is studied with the aim of reconstructing paleoenvironmental conditions and investigating abiotic and biotic factors, including predation, that influence the paleoecology and preservation potential of spatangoid echinoids. The echinoid fauna is dominated by the spatangoid Agassizia and, to a lesser extent, the clypeasteroid Clypeaster. The fauna also includes both regular (undetermined diadematoids and camarodonts) and irregular (Plagiobrissus, Echinocyamus, and Koehleraster) forms. Echinoids and associated fossil content, along with taphonomic and sedimentological signatures, indicate an inner sublittoral environment with moderate energy conditions affected by high-energy events. Agassizia remains, which consist mainly of complete and well-preserved tests, commonly bear subcircular drill holes that are interpreted as the result of cassid gastropod predation and investigated with respect to size selectivity and stereotypy of attack sites. Potential biases related to drilling predation and biostratinomy on the preservation potential of spatangoid tests are discussed. Agassizia lacks any morphological adaptation to minimize high predation risk, including defensive spines and the ability to burrow deeply into the sediment. An antipredator behavior possibly relied on a gregarious life-history strategy, reducing the frequency of attacks on specific individuals by cassid predators.",
    url = "https://doi.org/10.1017/jpa.2022.28",
    doi = "10.1017/jpa.2022.28",
    openalex = "W4224320736",
    references = "arachchige2019taxonomy, doi1010079783642697876, doi101016026481729390089b, doi101016jpalaeo201603024, doi101016jtecto201201026, doi101017jpa201720, doi101017s0094837300005352, doi101038293466a0, doi10108014772011003603556, doi1023071485138, doi1023073514687, openalexw1586846612, openalexw2474101076"
}

Organisms interacting with echinoids are common and produce diverse traces that are often distinctive and can be preserved in the fossil record. Thus, echinoids provide a wealth of information regarding the role of biotic interactions as drivers of ecological and morphological adaptations over macroevolutionary timescales. Studies documenting interactions with echinoids and the resulting traces have become more numerous. This Element reviews the ecologies of skeletal trace-producing interactions on echinoids in Modern ecosystems and the recognition of those biogenic traces in the fossil record. The authors explore diversification and morphological trends in Meso-Cenozoic echinoid clades and associated predator and parasite groups in the context of selective pressures brought about by the evolution of these biotic interactions. Their intent is that this review promotes additional studies documenting the intensity of biotic interactions with echinoids in both Recent and fossil assemblages and highlights their potential to advance our understanding of ecosystem functioning and evolution. This title is also available as Open Access on Cambridge Core.

@book{doi1010179781108893510,
    author = "Petsios, Elizabeth and Farrar, Lyndsey and Tennakoon, Shamindri and Jamal, Fatemah and Portell, Roger W. and Kowalewski, Michał and Tyler, Carrie L.",
    title = "The Ecology of Biotic Interactions in Echinoids",
    year = "2023",
    booktitle = "Cambridge University Press eBooks",
    abstract = "Organisms interacting with echinoids are common and produce diverse traces that are often distinctive and can be preserved in the fossil record. Thus, echinoids provide a wealth of information regarding the role of biotic interactions as drivers of ecological and morphological adaptations over macroevolutionary timescales. Studies documenting interactions with echinoids and the resulting traces have become more numerous. This Element reviews the ecologies of skeletal trace-producing interactions on echinoids in Modern ecosystems and the recognition of those biogenic traces in the fossil record. The authors explore diversification and morphological trends in Meso-Cenozoic echinoid clades and associated predator and parasite groups in the context of selective pressures brought about by the evolution of these biotic interactions. Their intent is that this review promotes additional studies documenting the intensity of biotic interactions with echinoids in both Recent and fossil assemblages and highlights their potential to advance our understanding of ecosystem functioning and evolution. This title is also available as Open Access on Cambridge Core.",
    url = "https://doi.org/10.1017/9781108893510",
    doi = "10.1017/9781108893510",
    openalex = "W4388745146",
    references = "doi1010160022098183900795, doi101016jpt200911001, doi1010179781108893411, doi1010179781108893510, doi101017s0094837300005352, doi101017s0094837300008174, doi1011300091761319980261091afrfoh23co2, doi1012019781003077831, doi1015159780691224244, doi1023071352125, openalexw1586846612"
}

The paper provides an overview of symbiotic relationships of echinoderms with each other and with other organisms throughout the Paleozoic era. The following groups of organisms are analyzed: cyanobacteria, corals (colonial and solitary), bryozoans, brachiopods, annelids, mollusks (gastropods), graptolites, as well as traces of symbiosis with organisms whose systematic position has not yet been identified. The criteria for establishing the lifetime or postmortem settlements of epibionts and the criteria for determining the type of symbiotic relationships are discussed.

@article{doi101134s0031030124601634,
    author = "Миранцев, Г. В. and Anekeeva, G. A. and Krutykh, A. A. and Рожнов, С. В.",
    title = "Symbiotic Relationships of Paleozoic Echinoderms",
    year = "2024",
    journal = "Paleontological Journal",
    abstract = "The paper provides an overview of symbiotic relationships of echinoderms with each other and with other organisms throughout the Paleozoic era. The following groups of organisms are analyzed: cyanobacteria, corals (colonial and solitary), bryozoans, brachiopods, annelids, mollusks (gastropods), graptolites, as well as traces of symbiosis with organisms whose systematic position has not yet been identified. The criteria for establishing the lifetime or postmortem settlements of epibionts and the criteria for determining the type of symbiotic relationships are discussed.",
    url = "https://doi.org/10.1134/s0031030124601634",
    doi = "10.1134/s0031030124601634",
    openalex = "W4408507286",
    references = "doi10100797814757074039, doi101007s0022700911923, doi101016jpalaeo201201027, doi1010179781108893510, doi101111j150239311978tb01229x, doi101111j150239311998tb00491x, doi101130mem81p1, doi101144pygs5211, doi1016690883135120030180435hopeeo20co2, doi103140bullgeosci1125, doi103354dao002205"
}

Exceptional preservation of macrobenthic invertebrates with articulated remains is typically explained by episodic rapid burial events or by onset of anoxia, both aborting mixing and disintegration processes. However, these scenarios do not explain the preservation of articulated remains of infaunal organisms in the Lower Miocene diatom-rich mudstones (Schlier-type deposits) in the Central Paratethys epicontinental sea. We show that bathyal macrobenthic assemblages and dominated by the shallow-burrowing echinoid Lovenia are best preserved in background mudstones with burrow-disrupted diatomaceous lamination, conforming to intermediate ichnofabric typical of hypoxic environments. Lovenia occurs in three types of assemblages that differ in preservation, size structure, and species diversity: (1) dispersed or clustered, frequently complete echinoid tests with spines occur in homogeneous or partially-laminated silty claystones; (2) sandy pavements with densely-packed, almost monospecific echinoid concentrations exhibit intermediate frequency of intact tests with spines; and (3) well-sorted echinoid fragments co-occur with plant remains in species-rich sandy lags. Alternation of laminae formed by Thalassionema or Coscinodiscus-dominated diatom assemblages with terrigenous laminae indicates that: (1) postmortem burial of echinoids below the taphonomically-active zone was induced by rapid export of ungrazed diatoms to the seafloor and by seasonal fallout of terrigenous muds from hypopycnal plumes or low-density hyperpycnal flows (rather than by sudden burial by thicker event beds); and that, (2) sediment mixing and irrigation rates were slow and patchy because the diatomaceous mats were not eliminated by echinoid and crustacean burrows and the laminae-forming diatom frustules remained intact. Although winnowing and test exhumation to sediment-water interface contributed to the formation of pavements with echinoid concentrations, their dense packing and low evenness can rather reflect population outbreaks of echinoids exploiting seasonal diatom fluxes to the sediment surface. The echinoid fragments with spines, dislocated remains with cross-plate fractures, and molluscs with sharp-edged margins in silty claystones suggest that some mortality events were induced by predation rather than by anoxia. Seasonal hypoxia was a key factor that limited test disintegration and displacement and thus preserved not only unique ichnofabric but also intact or dislocated, weakly time-averaged remains of benthic fauna adapted to hypoxic conditions.

@article{doi1018261let5744,
    author = "Tomášových, Adam and Galović, Ines and Hudáčková, Natália and Hyžný, Matúš and Ruman, Andrej and Rybár, Samuel and Šimo, Vladimír and Schlögl, Ján",
    title = "Articulated and dislocated infaunal echinoids as unique markers of hypoxic environments from the Miocene of Central Paratethys",
    year = "2024",
    journal = "Lethaia",
    abstract = "Exceptional preservation of macrobenthic invertebrates with articulated remains is typically explained by episodic rapid burial events or by onset of anoxia, both aborting mixing and disintegration processes. However, these scenarios do not explain the preservation of articulated remains of infaunal organisms in the Lower Miocene diatom-rich mudstones (Schlier-type deposits) in the Central Paratethys epicontinental sea. We show that bathyal macrobenthic assemblages and dominated by the shallow-burrowing echinoid Lovenia are best preserved in background mudstones with burrow-disrupted diatomaceous lamination, conforming to intermediate ichnofabric typical of hypoxic environments. Lovenia occurs in three types of assemblages that differ in preservation, size structure, and species diversity: (1) dispersed or clustered, frequently complete echinoid tests with spines occur in homogeneous or partially-laminated silty claystones; (2) sandy pavements with densely-packed, almost monospecific echinoid concentrations exhibit intermediate frequency of intact tests with spines; and (3) well-sorted echinoid fragments co-occur with plant remains in species-rich sandy lags. Alternation of laminae formed by Thalassionema or Coscinodiscus-dominated diatom assemblages with terrigenous laminae indicates that: (1) postmortem burial of echinoids below the taphonomically-active zone was induced by rapid export of ungrazed diatoms to the seafloor and by seasonal fallout of terrigenous muds from hypopycnal plumes or low-density hyperpycnal flows (rather than by sudden burial by thicker event beds); and that, (2) sediment mixing and irrigation rates were slow and patchy because the diatomaceous mats were not eliminated by echinoid and crustacean burrows and the laminae-forming diatom frustules remained intact. Although winnowing and test exhumation to sediment-water interface contributed to the formation of pavements with echinoid concentrations, their dense packing and low evenness can rather reflect population outbreaks of echinoids exploiting seasonal diatom fluxes to the sediment surface. The echinoid fragments with spines, dislocated remains with cross-plate fractures, and molluscs with sharp-edged margins in silty claystones suggest that some mortality events were induced by predation rather than by anoxia. Seasonal hypoxia was a key factor that limited test disintegration and displacement and thus preserved not only unique ichnofabric but also intact or dislocated, weakly time-averaged remains of benthic fauna adapted to hypoxic conditions.",
    url = "https://doi.org/10.18261/let.57.4.4",
    doi = "10.18261/let.57.4.4",
    openalex = "W4405217150",
    references = "doi101016jpalaeo201603024, doi1010179781108893411"
}

We described fossil teeth assigned to the orectolobiform shark genus, Cederstroemia collected from the tuffaceous sandstone of the Kashima Formation (Santonian) in the Oyubari area, Hokkaido, Japan. This is the first report of fossil remains of Cederstroemia from Asia. Due to the small number of specimens and their poor preservation, we left the studied material in open nomenclature as Cederstroemia sp. At the same time, the studied material may belong to a new previously undescribed morphology of Cederstroemia. The occurrence of Cederstroemia fossils in Japan indicates that this genus dispersed to the northwestern part of the Pacific Ocean in the Late Cretaceous, which considerably extends the range and previously known habitat of this genus.

@article{doi10541032039494222195,
    author = "KANEKO, MASAHIKO and Solonin, Sergey V.",
    title = "THE FIRST RECORD OF THE ORECTOLOBIFORM SHARK GENUS CEDERSTROEMIA (ELASMOBRANCHII, ORECTOLOBIDAE) IN ASIA (KASHIMA FORMATION, UPPER CRETACEOUS; OYUBARI AREA, HOKKAIDO, JAPAN)",
    year = "2024",
    journal = "RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA",
    abstract = "We described fossil teeth assigned to the orectolobiform shark genus, Cederstroemia collected from the tuffaceous sandstone of the Kashima Formation (Santonian) in the Oyubari area, Hokkaido, Japan. This is the first report of fossil remains of Cederstroemia from Asia. Due to the small number of specimens and their poor preservation, we left the studied material in open nomenclature as Cederstroemia sp. At the same time, the studied material may belong to a new previously undescribed morphology of Cederstroemia. The occurrence of Cederstroemia fossils in Japan indicates that this genus dispersed to the northwestern part of the Pacific Ocean in the Late Cretaceous, which considerably extends the range and previously known habitat of this genus.",
    url = "https://doi.org/10.54103/2039-4942/22195",
    doi = "10.54103/2039-4942/22195",
    openalex = "W4399807448",
    references = "doi101016jcretres200402004, doi101016jcretres201302002, doi101016jcretres2020104603, doi101016jcretres2023105779, doi101017jpa2020102, doi101080147720192013767286, doi1010801477201920171341960, doi101111j144017381994tb00115x, doi1016690883135120040190249nspffd20co2, doi105575geosoc10119"
}

Three tests of the holasteroid echinoid Hemipneustes striatoradiatus from the Belgian-Dutch type area of the Maastrichtian Stage preserving evidence of vertebrate-invertebrate interactions are documented and analysed. One specimen exhibits adoral pentagonal puncture marks, presumably made by the premaxillary teeth of Mosasaurus hoffmannii, together with a large aboral scar interpreted as resulting from an impact of the lower jaw. A second test preserves evidence of two separate attacks, the first by a mosasaur, presumably Plioplatecarpus marshi, leaving both a pentagonal adoral scar and a large aboral one, and the second by a shark, leaving non-penetrating small, deep triangular pits with tapering tails. A similar pitting is seen on the third test, arranged in clusters and here interpreted as a shark bite from above followed by a second bite subsequent to a 90° rotation of the echinoid. These finds provide the first unambiguous evidence of mosasaur predation on Hemipneustes and add to the sparse record of shark-echinoid interactions, suggesting that predation on large holasteroids by vertebrates was more frequent than previously recognised. All three tests also exhibit syn vivo and post-mortem invertebrate interactions, including also an undescribed serpulid.

@article{doi1020341gb2025011,
    author = "GOOLAERTS, Stijn",
    title = "Predator-prey dynamics in a latest Cretaceous marine ecosystem: mosasaur and shark attacks on the echinoid Hemipneustes striatoradiatus from the Maastrichtian type area (the Netherlands, Belgium)",
    year = "2025",
    journal = "Geologica Belgica",
    abstract = "Three tests of the holasteroid echinoid Hemipneustes striatoradiatus from the Belgian-Dutch type area of the Maastrichtian Stage preserving evidence of vertebrate-invertebrate interactions are documented and analysed. One specimen exhibits adoral pentagonal puncture marks, presumably made by the premaxillary teeth of Mosasaurus hoffmannii, together with a large aboral scar interpreted as resulting from an impact of the lower jaw. A second test preserves evidence of two separate attacks, the first by a mosasaur, presumably Plioplatecarpus marshi, leaving both a pentagonal adoral scar and a large aboral one, and the second by a shark, leaving non-penetrating small, deep triangular pits with tapering tails. A similar pitting is seen on the third test, arranged in clusters and here interpreted as a shark bite from above followed by a second bite subsequent to a 90° rotation of the echinoid. These finds provide the first unambiguous evidence of mosasaur predation on Hemipneustes and add to the sparse record of shark-echinoid interactions, suggesting that predation on large holasteroids by vertebrates was more frequent than previously recognised. All three tests also exhibit syn vivo and post-mortem invertebrate interactions, including also an undescribed serpulid.",
    url = "https://doi.org/10.20341/gb.2025.011",
    doi = "10.20341/gb.2025.011",
    openalex = "W7116126144",
    references = "doi101016jgr202505021, doi1010179781108893510, doi101186s13358024003416"
}

Echinoids are an integral part of present-day and ancient marine trophic webs, and they host a variety of mutualistic, commensalistic, and parasitic epibionts on their spines and test. Cidaroid echinoid (slate pencil urchins) spines in particular are commonly colonized by epizoans. Eucidaris in the western Atlantic and eastern Pacific today are notable for the frequency and intensity of calcifying, non-calcifying, and galling colonization on their spines. While moderate levels of spine colonization may provide camouflage and other benefits to the host, a high density of encrusters may instead reduce host fitness, and galling is invariably parasitic. Significant environmental changes in the equatorial and sub-equatorial western Atlantic and eastern Pacific necessitate a paleobiological approach to constrain the timing of changes in epibiosis intensity on Eucidaris. Here, we compare rates of spine colonization in present-day Eucidaris populations with ancestral Pliocene Eucidaris assemblages. We find that Pliocene spines show no evidence of parasitic galling, and significantly less evidence of epibiosis than their present-day descendants in both the Atlantic and Pacific. This holds true even after accounting for taphonomic processes that would preferentially erase evidence of non-calcifying colonization. We propose that the high intensity of colonization on present-day Eucidaris spines is a relatively recent development and may reflect human-induced habitat degradation in the region, underscoring the need for further investigation into this biotic interaction.

@article{doi103389fmars20251513138,
    author = "Petsios, Elizabeth and Fuchs, Corinne and Kowalewski, Michał and Larson, Paul and Portell, Roger W. and Tyler, Carrie L.",
    title = "Quaternary intensification of spine epibiosis in the cidaroid echinoid Eucidaris: implications for anthropogenic impacts",
    year = "2025",
    journal = "Frontiers in Marine Science",
    abstract = "Echinoids are an integral part of present-day and ancient marine trophic webs, and they host a variety of mutualistic, commensalistic, and parasitic epibionts on their spines and test. Cidaroid echinoid (slate pencil urchins) spines in particular are commonly colonized by epizoans. Eucidaris in the western Atlantic and eastern Pacific today are notable for the frequency and intensity of calcifying, non-calcifying, and galling colonization on their spines. While moderate levels of spine colonization may provide camouflage and other benefits to the host, a high density of encrusters may instead reduce host fitness, and galling is invariably parasitic. Significant environmental changes in the equatorial and sub-equatorial western Atlantic and eastern Pacific necessitate a paleobiological approach to constrain the timing of changes in epibiosis intensity on Eucidaris. Here, we compare rates of spine colonization in present-day Eucidaris populations with ancestral Pliocene Eucidaris assemblages. We find that Pliocene spines show no evidence of parasitic galling, and significantly less evidence of epibiosis than their present-day descendants in both the Atlantic and Pacific. This holds true even after accounting for taphonomic processes that would preferentially erase evidence of non-calcifying colonization. We propose that the high intensity of colonization on present-day Eucidaris spines is a relatively recent development and may reflect human-induced habitat degradation in the region, underscoring the need for further investigation into this biotic interaction.",
    url = "https://doi.org/10.3389/fmars.2025.1513138",
    doi = "10.3389/fmars.2025.1513138",
    openalex = "W4409205255",
    references = "doi101016003101829090178a, doi101016jtree201009010, doi1010179781108893510, doi101038078267a0, doi101126sciadv1600883, doi101126science1059199, doi101126scienceaah4787, doi101130b305281, openalexw45809738, openalexw615408771, openalexw642360549"
}