Conodonts

The Devonian and Carboniferous formations of Missouri and Kansas contain an abundant conodont fauna. From the Fort Scott limestone the writer describes 3 new genera and several new species. Reconnaissance collecting and study of conodonts from Missouri, Kansas, and Oklahoma has shown that they are abundant in the Snyder Creek shale of the Devonian, the Grassy Creek shale, Louisiana limestone, Glen Park formation, Hannibal sandstone, Sylamore sandstone, Bushberg sandstone, and Fern Glen formation of the Mississippian. In the Pennsylvanian, conodonts occur abundantly in the Cherokee, Henrietta, Kansas City, Lansing, Shawnee and Wabaunsee formations, and channel sandstone of uncertain Pennsylvanian age. These minute teeth and scales are also found in the Permian of Kansas. The types of sediments which the writer has found to contain conodonts are in order of abundance shale, sandstone, conglomerate, and limestone. A three pound sample from a shale member of one Pennsylvanian formation contained twelve genera. Although the great'variety of forms from this sample is probably not a true indication of conodont distribution in Carboniferous formations, it does not exaggerate their abundance in some members. Undoubtedly conodonts have large geographic and stratigraphic distribution. It is probably because of their microscopic size and most abundant occurrence in sediments devoid of other fossils that paleontologists have neglected them. Pennsylvanian conodonts consist of minute plates, teeth, and scales most of which are brown in color and show a pearly luster. This assemblage together with the presence of forms which resemble small sharks' teeth is evidence that conodonts are fishes. The evolution of different species in the Mississippian and Pennsylvanian periods was more or less gradational, yet specific differences are numerous.

@article{openalexw2614833179,
    author = "Gunnell, F",
    title = "Conodonts from the Fort Scott limestone of Missouri",
    year = "1931",
    journal = "Journal of Paleontology",
    abstract = "The Devonian and Carboniferous formations of Missouri and Kansas contain an abundant conodont fauna. From the Fort Scott limestone the writer describes 3 new genera and several new species. Reconnaissance collecting and study of conodonts from Missouri, Kansas, and Oklahoma has shown that they are abundant in the Snyder Creek shale of the Devonian, the Grassy Creek shale, Louisiana limestone, Glen Park formation, Hannibal sandstone, Sylamore sandstone, Bushberg sandstone, and Fern Glen formation of the Mississippian. In the Pennsylvanian, conodonts occur abundantly in the Cherokee, Henrietta, Kansas City, Lansing, Shawnee and Wabaunsee formations, and channel sandstone of uncertain Pennsylvanian age. These minute teeth and scales are also found in the Permian of Kansas. The types of sediments which the writer has found to contain conodonts are in order of abundance shale, sandstone, conglomerate, and limestone. A three pound sample from a shale member of one Pennsylvanian formation contained twelve genera. Although the great'variety of forms from this sample is probably not a true indication of conodont distribution in Carboniferous formations, it does not exaggerate their abundance in some members. Undoubtedly conodonts have large geographic and stratigraphic distribution. It is probably because of their microscopic size and most abundant occurrence in sediments devoid of other fossils that paleontologists have neglected them. Pennsylvanian conodonts consist of minute plates, teeth, and scales most of which are brown in color and show a pearly luster. This assemblage together with the presence of forms which resemble small sharks' teeth is evidence that conodonts are fishes. The evolution of different species in the Mississippian and Pennsylvanian periods was more or less gradational, yet specific differences are numerous.",
    openalex = "W2614833179"
}

@article{doi102475ajss525147193,
    author = "Harris, R. W. and Hollingsworth, Richard",
    title = "New Pennsylvanian conodonts from Oklahoma",
    year = "1933",
    journal = "American Journal of Science",
    url = "https://doi.org/10.2475/ajs.s5-25.147.193",
    doi = "10.2475/ajs.s5-25.147.193",
    openalex = "W2333731446"
}

@article{openalexw2613102951,
    author = "Ellison, Samuel P.",
    title = "The composition of conodonts",
    year = "1944",
    journal = "Journal of Paleontology",
    openalex = "W2613102951"
}

@article{openalexw2728042400,
    author = "Youngquist, Walter Lewellyn and Downs, Harold Robert",
    title = "Additional conodonts from the Pennsylvanian of Iowa",
    year = "1949",
    journal = "Journal of Paleontology",
    openalex = "W2728042400"
}

@article{openalexw2600301146,
    author = "Rhodes, Frank H. T.",
    title = "A classification of Pennsylvanian conodont assemblages",
    year = "1952",
    journal = "Journal of Paleontology",
    openalex = "W2600301146"
}

(1954). Conodonts from the lowermost Ordovician strata of South-Central Sweden. Geologiska Foreningen i Stockholm Forhandlingar: Vol. 76, No. 4, pp. 517-604.

@article{doi10108011035895409453581,
    author = "Lindström, Maurits",
    title = "Conodonts from the lowermost Ordovician strata of South-Central Sweden",
    year = "1954",
    journal = "Geologiska Föreningen i Stockholm Förhandlingar",
    abstract = "(1954). Conodonts from the lowermost Ordovician strata of South-Central Sweden. Geologiska Foreningen i Stockholm Forhandlingar: Vol. 76, No. 4, pp. 517-604.",
    url = "https://doi.org/10.1080/11035895409453581",
    doi = "10.1080/11035895409453581",
    openalex = "W1986840221",
    references = "doi1023072421322"
}

SUMMARY Conodonts are minute, tooth‐like fossils, which exhibit considerable variation in form. Two main types of structure are recognizable, laminated and fibrous. Lamellar conodonts occur in sedimentary rocks from Ordovician to Triassic, while fibrous conodonts appear to be confined to the Ordovician. Conodonts have been classified as isolated specimens, upon which a binomial system of classification has been erected. This classification does not, however, represent a true zoological classification, since recent work has shown that a number of ‘form‐genera’ appear to have been present in an individual conodont‐bearing animal. This has formed the basis for a zoological classification, which now exists alongside the earlier ‘form‐classification’. The fibrous conodonts are frequently attached to basal ‘bone‐like’ material. They are apparently confined to the Ordovician, and this suggests that they may represent a distinct group from the lamellar conodonts. The main variations in form in the lamellar conodonts are described. The basal cavity of the lamellar conodonts is variable in form. Keels are developed on the aboral surfaces of a number of types, and a few lamellar conodonts are attached to bone‐like material. Their microstructure indicates that conodonts were formed by accretion around a basal cavity. The presence of radial canals, extending from the basal cavity to the surface of the units, has been detected. Conodonts are composed of calcium phosphate which has the structure of the apatite series. Analysis shows their composition to be essentially similar to that of the ‘bone‐like’ material to which they are sometimes attached, ridged, bone‐like, fragmentary plates, found associated with the conodonts and a typical Devonian fish‐plate fragment. There appears to be no difference in composition between the fibrous and the lamellar conodonts. Specimens are recorded in which broken parts of conodonts appear to have been regenerated. The significance of this is discussed. Palaeontological studies indicate that the conodont‐bearing animals were adapted to a wide variety of shallow‐water, marine environments. Natural conodont assemblages appear to indicate that conodonts are paired, generally in an antero‐posteriorly elongated arrangement. A single assemblage may contain 14–22 component conodonts, representing 3–5 different ‘form‐genera’. Conodonts are extinct, having existed from Ordovician to Triassic times. Their geological history is discussed and compared with the histories of other animal groups. The denticulated jaw Archeognathus may not necessarily represent a group of fibrous conodonts. It is, however, similar to these, and its form tends to support the theory that fibrous conodonts represent a distinct group of animals from those which bore the lamellar conodonts. The structures on a specimen of Coelacanthus lepturus described by Demanet do not appear to represent conodonts. The arrangement, form, number, chemical composition and faunal associations of conodonts do not appear to favour the theories of their crustacean or molluscan origin. The suggestion of the skeletal function of conodonts does not appear to be favoured by their general form, their assemblage occurrences or the form of their basal cavity. The evidence for the suggestion of the annelid affinities of the conodonts is discussed. The significance of the chemical composition of the conodonts is considered. The chemical composition, size and general form of conodonts, and the arrangement of conodont assemblages, appear to contradict the theory that they functioned as copulatory structures in worms. The reasons for regarding the conodonts as being parts of fish are discussed. The two most important are the chemical composition and the basal attachment of conodonts, but neither of these appears to offer conclusive evidence of the origin of conodonts from fishes. It is suggested that, if the vertebrate origin of conodonts is accepted, they may represent some group of vertebrates, other than fishes, now extinct, and apart from the conodonts, entirely unknown. It is suggested that the general lack of wear, form, size and assemblage arrangement of conodonts tend to support a theory of their annelid affinities. The main problem appears to be whether the internal secretion of calcium phosphate must be regarded as an indication of vertebrate, rather than invertebrate, origin. The answer to this problem largely determines whether the conodonts are considered as representing vertebrates or worm‐like creatures. It is suggested that the present state of knowledge does not justify a final conclusion as to the affinities of the conodonts, although they appear to represent an extinct group of either worm‐like creatures or primitive vertebrates. It is a pleasure to acknowledge the assistance given by Mr Adrian P. Rhodes in preparing Figs. 1 and 3, Mr Roy Philips for his section on the composition of conodonts, Prof. Harold Scott, of the University of Illinois, for a number of helpful discussions on this subject, Prof. James Cullison, of Florida State University, for supplying information on Archeognathus, Prof. J. B. Cragg and Dr John Phillipson for reading the manuscript, Dr George Kohnstam for translating a paper, Mr G. O'Neill and Mrs J. Harker for assistance in the preparation of the illustrations, and the secretarial staff of the Geology Department of the Durham Colleges for their assistance in the preparation of the typescript.

@article{doi101111j1469185x1954tb01518x,
    author = "Rhodes, Frank H. T. and Phillips, R.",
    title = "THE ZOOLOGICAL AFFINITIES OF THE CONODONTS",
    year = "1954",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "SUMMARY Conodonts are minute, tooth‐like fossils, which exhibit considerable variation in form. Two main types of structure are recognizable, laminated and fibrous. Lamellar conodonts occur in sedimentary rocks from Ordovician to Triassic, while fibrous conodonts appear to be confined to the Ordovician. Conodonts have been classified as isolated specimens, upon which a binomial system of classification has been erected. This classification does not, however, represent a true zoological classification, since recent work has shown that a number of ‘form‐genera’ appear to have been present in an individual conodont‐bearing animal. This has formed the basis for a zoological classification, which now exists alongside the earlier ‘form‐classification’. The fibrous conodonts are frequently attached to basal ‘bone‐like’ material. They are apparently confined to the Ordovician, and this suggests that they may represent a distinct group from the lamellar conodonts. The main variations in form in the lamellar conodonts are described. The basal cavity of the lamellar conodonts is variable in form. Keels are developed on the aboral surfaces of a number of types, and a few lamellar conodonts are attached to bone‐like material. Their microstructure indicates that conodonts were formed by accretion around a basal cavity. The presence of radial canals, extending from the basal cavity to the surface of the units, has been detected. Conodonts are composed of calcium phosphate which has the structure of the apatite series. Analysis shows their composition to be essentially similar to that of the ‘bone‐like’ material to which they are sometimes attached, ridged, bone‐like, fragmentary plates, found associated with the conodonts and a typical Devonian fish‐plate fragment. There appears to be no difference in composition between the fibrous and the lamellar conodonts. Specimens are recorded in which broken parts of conodonts appear to have been regenerated. The significance of this is discussed. Palaeontological studies indicate that the conodont‐bearing animals were adapted to a wide variety of shallow‐water, marine environments. Natural conodont assemblages appear to indicate that conodonts are paired, generally in an antero‐posteriorly elongated arrangement. A single assemblage may contain 14–22 component conodonts, representing 3–5 different ‘form‐genera’. Conodonts are extinct, having existed from Ordovician to Triassic times. Their geological history is discussed and compared with the histories of other animal groups. The denticulated jaw Archeognathus may not necessarily represent a group of fibrous conodonts. It is, however, similar to these, and its form tends to support the theory that fibrous conodonts represent a distinct group of animals from those which bore the lamellar conodonts. The structures on a specimen of Coelacanthus lepturus described by Demanet do not appear to represent conodonts. The arrangement, form, number, chemical composition and faunal associations of conodonts do not appear to favour the theories of their crustacean or molluscan origin. The suggestion of the skeletal function of conodonts does not appear to be favoured by their general form, their assemblage occurrences or the form of their basal cavity. The evidence for the suggestion of the annelid affinities of the conodonts is discussed. The significance of the chemical composition of the conodonts is considered. The chemical composition, size and general form of conodonts, and the arrangement of conodont assemblages, appear to contradict the theory that they functioned as copulatory structures in worms. The reasons for regarding the conodonts as being parts of fish are discussed. The two most important are the chemical composition and the basal attachment of conodonts, but neither of these appears to offer conclusive evidence of the origin of conodonts from fishes. It is suggested that, if the vertebrate origin of conodonts is accepted, they may represent some group of vertebrates, other than fishes, now extinct, and apart from the conodonts, entirely unknown. It is suggested that the general lack of wear, form, size and assemblage arrangement of conodonts tend to support a theory of their annelid affinities. The main problem appears to be whether the internal secretion of calcium phosphate must be regarded as an indication of vertebrate, rather than invertebrate, origin. The answer to this problem largely determines whether the conodonts are considered as representing vertebrates or worm‐like creatures. It is suggested that the present state of knowledge does not justify a final conclusion as to the affinities of the conodonts, although they appear to represent an extinct group of either worm‐like creatures or primitive vertebrates. It is a pleasure to acknowledge the assistance given by Mr Adrian P. Rhodes in preparing Figs. 1 and 3, Mr Roy Philips for his section on the composition of conodonts, Prof. Harold Scott, of the University of Illinois, for a number of helpful discussions on this subject, Prof. James Cullison, of Florida State University, for supplying information on Archeognathus, Prof. J. B. Cragg and Dr John Phillipson for reading the manuscript, Dr George Kohnstam for translating a paper, Mr G. O'Neill and Mrs J. Harker for assistance in the preparation of the illustrations, and the secretarial staff of the Geology Department of the Durham Colleges for their assistance in the preparation of the typescript.",
    url = "https://doi.org/10.1111/j.1469-185x.1954.tb01518.x",
    doi = "10.1111/j.1469-185x.1954.tb01518.x",
    openalex = "W1894623900"
}

@article{rexroad1958the3,
    author = "Rexroad, C. B",
    title = "The conodont homeomorphs Taphrognathus and Streptognathodus",
    year = "1958",
    journal = "Journal of Paleontology, v. 32, p. 1158-1159",
    note = "talkorigins\_source = {true}; raw\_reference = {Rexroad, C. B., 1958, The conodont homeomorphs Taphrognathus and Streptognathodus: Journal of Paleontology, v. 32, p. 1158-1159.}"
}

@article{scott1959intraspecific4,
    author = "Scott, A. J. and Collinson, C",
    title = "Intraspecific variability in conodonts - Palmatolepis glabra Ulrich \& Bassler",
    year = "1959",
    journal = "Journal of Paleontology, v. 33, p. 550-565",
    note = "talkorigins\_source = {true}; raw\_reference = {Scott, A. J., and Collinson, C., 1959, Intraspecific variability in conodonts - Palmatolepis glabra Ulrich \& Bassler: Journal of Paleontology, v. 33, p. 550-565.}"
}

The Scottish Carboniferous conodonts described by Hinde and figured by Smith in 1900 are refigured and redescribed. Additional specimens from the John Smith collection and from the writer's own collection are described. Sixteen genera of conodonts are shown to be present in the Scottish Carboniferous and thirty species, of which seventeen are new, are described. Correlation of the Scottish Carboniferous Limestone Series with the Upper Mississippian is indicated by the conodont fauna.

@article{doi101144transed1811,
    author = "Clarke, William",
    title = "Scottish Carboniferous conodonts",
    year = "1960",
    journal = "Transactions of the Edinburgh Geological Society",
    abstract = "The Scottish Carboniferous conodonts described by Hinde and figured by Smith in 1900 are refigured and redescribed. Additional specimens from the John Smith collection and from the writer's own collection are described. Sixteen genera of conodonts are shown to be present in the Scottish Carboniferous and thirty species, of which seventeen are new, are described. Correlation of the Scottish Carboniferous Limestone Series with the Upper Mississippian is indicated by the conodont fauna.",
    url = "https://doi.org/10.1144/transed.18.1.1",
    doi = "10.1144/transed.18.1.1",
    openalex = "W2038745462"
}

The conodont faunas of the St. Louis Formation were studied from the longest and best exposures in the Mississippian outcrop belt around the Illinois Basin, including type sections of both the St. Louis and Ste.Genevieve Formations.Faunas were found to be common in the upper part of the St. Louis but sparse in the lower.Altogether they consist of 2 1 species, representing the genera Apatognathus?, Cavusgnathus, Hibbardella, Ligonodina, Lonchodina, Magnilaterella, n.gen., Neoprioniodus, Ozarkodina, Spathognathodus, Taphrognathus and one un- named new genus.Three new taxa, Magnilaterella, n.gen., Magnilaterella robusta, n.sp., and Ozarkodina laevipostica, n.sp., are proposed herein.Two genera from the St. Louis are especially useful for biostratigraphic zonation: Taphrognathus was found to occur only as high as the middle of the formation and Cavusgnathus no lower than the middle.In addition, three species, Apatognathus?gemma, A? porcata, and Spathognathodus scitulus, are common and.confined to the upper part of the formation.In general, the conodont faunas of the St. Louis are transitional with those of the underlying Warsaw and Salem Forma- tions and are abruptly different from faunas of the overlying Ste.Genevieve Formation.Within the St. Louis there are distinctive but transitional faunal differences between upper and lower parts of the formation.

@article{openalexw1167734374,
    author = "Rexroad, Carl B. and Collinson, Charles William",
    title = "Conodonts from the St. Louis formation (Valmeyeran series) of Illinois, Indiana, and Missouri",
    year = "1963",
    journal = "IDEALS (University of Illinois Urbana-Champaign)",
    abstract = "The conodont faunas of the St. Louis Formation were studied from the longest and best exposures in the Mississippian outcrop belt around the Illinois Basin, including type sections of both the St. Louis and Ste.Genevieve Formations.Faunas were found to be common in the upper part of the St. Louis but sparse in the lower.Altogether they consist of 2 1 species, representing the genera Apatognathus?, Cavusgnathus, Hibbardella, Ligonodina, Lonchodina, Magnilaterella, n.gen., Neoprioniodus, Ozarkodina, Spathognathodus, Taphrognathus and one un- named new genus.Three new taxa, Magnilaterella, n.gen., Magnilaterella robusta, n.sp., and Ozarkodina laevipostica, n.sp., are proposed herein.Two genera from the St. Louis are especially useful for biostratigraphic zonation: Taphrognathus was found to occur only as high as the middle of the formation and Cavusgnathus no lower than the middle.In addition, three species, Apatognathus?gemma, A? porcata, and Spathognathodus scitulus, are common and.confined to the upper part of the formation.In general, the conodont faunas of the St. Louis are transitional with those of the underlying Warsaw and Salem Forma- tions and are abruptly different from faunas of the overlying Ste.Genevieve Formation.Within the St. Louis there are distinctive but transitional faunal differences between upper and lower parts of the formation.",
    openalex = "W1167734374"
}

@article{doi1014825prpsj1951196453179,
    author = "Igô, Hisayoshi and Koike, Toshio",
    title = "466. CARBONIFEROUS CONODONTS FROM THE OMI LIMESTONE, NIIGATA PREFECTURE. CENTRAL JAPAN (STUDIES OF ASIAN CONODONTS, PART I)",
    year = "1964",
    journal = "Transactions and proceedings of the Paleontological Society of Japan. New series",
    url = "https://doi.org/10.14825/prpsj1951.1964.53\_179",
    doi = "10.14825/prpsj1951.1964.53\_179",
    openalex = "W2515438718"
}

A Late Mississippian conodont fauna is recorded from the lower part of the Bird Spring Formation near Lee Canyon, Clark County, Nev. The fauna comprises eight species referred to the genera Cavusgnathus Harris and Hollingsworth, Gnathodus Pander, Streptognathodus Stauffer and Plummer, Spathognathodus Branson and Mehl, Ozarkodina Branson and Mehl, and several unidentified species of Hindeodus Rexroad and Furnish. Cavusgnathus muricata n. sp. and Gnathodus girtyi simplex n. subsp. are described and illustrated. This Nevada conodont assemblage suggests that the enclosing strata are the approximate time equivalent of the Grove Church Formation of the standard Chesterian (Late Mississippian) section.

@article{openalexw2336167968,
    author = "Dunn, David L.",
    title = "Late Mississippian conodonts from the Bird Spring Formation in Nevada",
    year = "1965",
    journal = "Journal of Paleontology",
    abstract = "A Late Mississippian conodont fauna is recorded from the lower part of the Bird Spring Formation near Lee Canyon, Clark County, Nev. The fauna comprises eight species referred to the genera Cavusgnathus Harris and Hollingsworth, Gnathodus Pander, Streptognathodus Stauffer and Plummer, Spathognathodus Branson and Mehl, Ozarkodina Branson and Mehl, and several unidentified species of Hindeodus Rexroad and Furnish. Cavusgnathus muricata n. sp. and Gnathodus girtyi simplex n. subsp. are described and illustrated. This Nevada conodont assemblage suggests that the enclosing strata are the approximate time equivalent of the Grove Church Formation of the standard Chesterian (Late Mississippian) section.",
    openalex = "W2336167968"
}

All late Devonian conodonts available from sedimentary facies of the Lennard Shelf, Canning basin, Western Australia, are described. The maximum abundance of conodonts is found in direct association with ammonoids in the inter-reef facies represented by the Gogo formation, and in the fore-reef and inter-reef facies of the Virgin Hills formation. Associations of certain conodont and ammonoid taxa are identical with those in the classic antipodal Rhenish Schiefergebirge of Germany. Distribution patterns show that the conodont and ammonoid zones are geologically homochronous on a mondial basis. Playfordia n.gen. (conodont) and Ancyrodella rotundiloba alata n.subsp. are described.

@article{openalexw2615668145,
    author = "Glenister, Brian F. and Klapper, Gilbert",
    title = "Upper Devonian conodonts from the Canning Basin, Western Australia",
    year = "1966",
    journal = "Journal of Paleontology",
    abstract = "All late Devonian conodonts available from sedimentary facies of the Lennard Shelf, Canning basin, Western Australia, are described. The maximum abundance of conodonts is found in direct association with ammonoids in the inter-reef facies represented by the Gogo formation, and in the fore-reef and inter-reef facies of the Virgin Hills formation. Associations of certain conodont and ammonoid taxa are identical with those in the classic antipodal Rhenish Schiefergebirge of Germany. Distribution patterns show that the conodont and ammonoid zones are geologically homochronous on a mondial basis. Playfordia n.gen. (conodont) and Ancyrodella rotundiloba alata n.subsp. are described.",
    openalex = "W2615668145"
}

@misc{klapper1967evolutionary2,
    author = "Klapper, G. and Ziegler, W",
    title = "Evolutionary development of the Icriodus latericresens group (Conodonta) in the Devonian of Europe and North America",
    year = "1967",
    howpublished = "Palaeontographica, Series A, v. 127, p. 68-83",
    note = "talkorigins\_source = {true}; raw\_reference = {Klapper, G., and Ziegler, W., 1967, Evolutionary development of the Icriodus latericresens group (Conodonta) in the Devonian of Europe and North America: Palaeontographica, Series A, v. 127, p. 68-83.}"
}

@article{openalexw2753772898,
    author = "Lane, H. Richard",
    title = "Uppermost Mississippian and Lower Pennsylvanian conodonts from the type Morrowan region, Arkansas",
    year = "1967",
    journal = "Journal of Paleontology",
    openalex = "W2753772898",
    references = "doi101144transed1811, doi1014825prpsj1951196453179, doi102475ajss525147193, doi105962bhltitle61669, openalexw2336167968, openalexw2593019349, openalexw2597080739, openalexw2614833179, openalexw2728042400, openalexw2735133573"
}

Of the four symmetry classes of conodont element-pairs recognized herein, two involve asymmetry. Asymmetry in the conodont-bearing organism need not preclude the concept of a nektonic mode of life, but it is clear that each conodont element was not part of a mirror-imaged pair. Interestingly, three of the four possible symmetry classes of conodont element-pairs are currently known to exist among scolecodont element-pairs of the polychaete jaw apparatus. Although not of suprageneric importance, the symmetry classification of conodont element-pairs is helpful in conodont taxonomy and can be useful in deciphering conodont lineages.

@article{openalexw2598746693,
    author = "Lane, H. Richard",
    title = "Symmetry in conodont element-pairs",
    year = "1968",
    journal = "Journal of Paleontology",
    abstract = "Of the four symmetry classes of conodont element-pairs recognized herein, two involve asymmetry. Asymmetry in the conodont-bearing organism need not preclude the concept of a nektonic mode of life, but it is clear that each conodont element was not part of a mirror-imaged pair. Interestingly, three of the four possible symmetry classes of conodont element-pairs are currently known to exist among scolecodont element-pairs of the polychaete jaw apparatus. Although not of suprageneric importance, the symmetry classification of conodont element-pairs is helpful in conodont taxonomy and can be useful in deciphering conodont lineages.",
    openalex = "W2598746693",
    references = "openalexw1167734374, openalexw1909333764, openalexw2600301146, openalexw2615668145"
}

@article{doi105962p310413,
    author = "Rhodes, Frank H. T. and Austin, Ronald L. and Druce, Deric Charles",
    title = "British Avonian (Carboniferous) Conodont faunas, and their value in the local and intercontinental correlation",
    year = "1969",
    journal = "Bulletin of the British Museum (Natural History) Geology Supplement",
    url = "https://doi.org/10.5962/p.310413",
    doi = "10.5962/p.310413",
    openalex = "W639074227"
}

@article{openalexw2207565996,
    author = "Miller, James F.",
    title = "Conodont fauna of the Notch Peak limestone (Cambro-Ordovician), House range, Utah",
    year = "1969",
    journal = "Journal of Paleontology",
    openalex = "W2207565996",
    references = "doi10108011035895409453581"
}

The conodonts are divided into the Westergaardodinida and Conodontophorida orders. The latter (conodonts proper) are divided into 8 superfamilies. The Distacodontacea (Proconodontidae, Clavohamulidae, and Distacodontidae families) are on the whole a simple, ‘primitive’ group. The Chirognathacea include Oistodus (s.str.), Chirognathus, and Rhipidognathus. The Panderodontacea are mainly simple cones. The Prioniodinacea have compound, non‐blade elements. The Prioniodontacea include the Periodontidae, Prioniodontidae, Balognathidae, and Icriodontidae families. Bryantodontace, Gondolellacea, and Polygnathacea are based on platform‐stock genera. The Polygnathacea (spathognathodon‐tids, polygnathids, and indiognathodontids) may comprise two major stocks independent since the Ordovician.

@article{doi101111j150239311970tb00834x,
    author = "Lindström, Maurits",
    title = "A SUPRAGENERIC TAXONOMY OF THE CONODONTS",
    year = "1970",
    journal = "Lethaia",
    abstract = "The conodonts are divided into the Westergaardodinida and Conodontophorida orders. The latter (conodonts proper) are divided into 8 superfamilies. The Distacodontacea (Proconodontidae, Clavohamulidae, and Distacodontidae families) are on the whole a simple, ‘primitive’ group. The Chirognathacea include Oistodus (s.str.), Chirognathus, and Rhipidognathus. The Panderodontacea are mainly simple cones. The Prioniodinacea have compound, non‐blade elements. The Prioniodontacea include the Periodontidae, Prioniodontidae, Balognathidae, and Icriodontidae families. Bryantodontace, Gondolellacea, and Polygnathacea are based on platform‐stock genera. The Polygnathacea (spathognathodon‐tids, polygnathids, and indiognathodontids) may comprise two major stocks independent since the Ordovician.",
    url = "https://doi.org/10.1111/j.1502-3931.1970.tb00834.x",
    doi = "10.1111/j.1502-3931.1970.tb00834.x",
    openalex = "W2021716809",
    references = "doi101007bf03044446, doi101127zdgg1111959434, doi101130mem127p21, openalexw2207565996, openalexw2753772898"
}

@book{doi101130mem127,
    title = "Symposium on Conodont Biostratigraphy",
    year = "1970",
    booktitle = "Geological Society of America eBooks",
    url = "https://doi.org/10.1130/mem127",
    doi = "10.1130/mem127",
    openalex = "W4253476977"
}

In Europe, a Lower Ordovician conodont zonation can be established for the calcareous, partially condensed succession of the Baltic Shield. Sporadic conodont occurrences in the graptolitic shale facies can be correlated with this zonation. The Tremadocian to Llanvirnian Series are dealt with, and eleven conodont zones are established in these series. From below, these are the zones of Cordylodus angulatus, Paltodus deltifer (both Tremadocian), Paroistodus proteus, Prioniodus elegans, P. evae (corresponding to the Arenigian extensus Zone), Baltoniodus triangularis, B. navis, Paroistodus originalis, Microzarkodina parva (corresponding to the main part of the Arenigian hirundo Zone), and Amorphognathus variabilis (top of hirundo Zone, Llanvirnian bifidus Zone). For handling the material, some new taxa have had to be described. The taxonomy is based on multielement species, where such can be established. The multielement species are defined on morphologic and statistical criteria, as well as on the pattern of evolution. The taxonomic approach allows a more "natural" classification on the suprageneric level than the form-taxonomy previously used for this material. An evolutionary pattern is discernible for the drepnodids (each species containing drepanodiform and oistodiform elements) and the prioniodids (species containing prioniodiform elements, branched compound elements with symmetry transition, and oistodiform elements). On a suggestion from Professor O. H. Walliser, elements belonging to multielement species are distinguished by adding the ending "-form" to the name of the genus they would have been brought to in a purely formal taxonomy. The word formed in this way is an adjective. The following new taxa are named: Drepanoistodus gen. nov., Paroistodus, gen. nov., Protopanderodus, gen. nov., Stolodus, gen. nov., Baltoniodus, gen. nov., Microzarkodina, gen. nov., Microzarkodina parva n. sp., M. ozarkodella n. sp. The following genera are redefined: Oistodus, Scandodus, Scolopodus, Drepanodus, Paltodus, Prioniodus, Gothodus.

@incollection{doi101130mem127p21,
    author = "Lindström, Maurits",
    title = "Lower Ordovician Conodonts of Europe",
    year = "1970",
    booktitle = "Memoir - Geological Society of America",
    abstract = {In Europe, a Lower Ordovician conodont zonation can be established for the calcareous, partially condensed succession of the Baltic Shield. Sporadic conodont occurrences in the graptolitic shale facies can be correlated with this zonation. The Tremadocian to Llanvirnian Series are dealt with, and eleven conodont zones are established in these series. From below, these are the zones of Cordylodus angulatus, Paltodus deltifer (both Tremadocian), Paroistodus proteus, Prioniodus elegans, P. evae (corresponding to the Arenigian extensus Zone), Baltoniodus triangularis, B. navis, Paroistodus originalis, Microzarkodina parva (corresponding to the main part of the Arenigian hirundo Zone), and Amorphognathus variabilis (top of hirundo Zone, Llanvirnian bifidus Zone). For handling the material, some new taxa have had to be described. The taxonomy is based on multielement species, where such can be established. The multielement species are defined on morphologic and statistical criteria, as well as on the pattern of evolution. The taxonomic approach allows a more "natural" classification on the suprageneric level than the form-taxonomy previously used for this material. An evolutionary pattern is discernible for the drepnodids (each species containing drepanodiform and oistodiform elements) and the prioniodids (species containing prioniodiform elements, branched compound elements with symmetry transition, and oistodiform elements). On a suggestion from Professor O. H. Walliser, elements belonging to multielement species are distinguished by adding the ending "-form" to the name of the genus they would have been brought to in a purely formal taxonomy. The word formed in this way is an adjective. The following new taxa are named: Drepanoistodus gen. nov., Paroistodus, gen. nov., Protopanderodus, gen. nov., Stolodus, gen. nov., Baltoniodus, gen. nov., Microzarkodina, gen. nov., Microzarkodina parva n. sp., M. ozarkodella n. sp. The following genera are redefined: Oistodus, Scandodus, Scolopodus, Drepanodus, Paltodus, Prioniodus, Gothodus.},
    url = "https://doi.org/10.1130/mem127-p21",
    doi = "10.1130/mem127-p21",
    openalex = "W2506836352"
}

Detailed investigations of the stratigraphically remarkably complete Middle and Upper Ordovician succession in Sweden have permitted recognition of a sequence of five main conodont zones and ten subzones, principally based on evolutionary changes in rapidly evolving stocks of multielement species. Zonal fossils include species of Amorphognathus, Eoplacognathus, Prioniodus, and Pygodus. The Pygodus serrus, the Pygodus anserinus, the Amorphognathus tvaerensis, and the lower part of the Amorphognathus superbus Zones are Middle Ordovician, the upper part of the Amorphognathus superbus and the Amorphognathus ordovicicus Zones are Upper Ordovician in age. The Pygodus serrus Zone is subdivided into five, the Pygodus anserinus Zone...

@incollection{doi101130mem127p83,
    author = "Bergström, Stig M.",
    title = "Conodont Biostratigraphy of the Middle and Upper Ordovician of Europe and Eastern North America",
    year = "1970",
    booktitle = "Memoir - Geological Society of America",
    abstract = "Detailed investigations of the stratigraphically remarkably complete Middle and Upper Ordovician succession in Sweden have permitted recognition of a sequence of five main conodont zones and ten subzones, principally based on evolutionary changes in rapidly evolving stocks of multielement species. Zonal fossils include species of Amorphognathus, Eoplacognathus, Prioniodus, and Pygodus. The Pygodus serrus, the Pygodus anserinus, the Amorphognathus tvaerensis, and the lower part of the Amorphognathus superbus Zones are Middle Ordovician, the upper part of the Amorphognathus superbus and the Amorphognathus ordovicicus Zones are Upper Ordovician in age. The Pygodus serrus Zone is subdivided into five, the Pygodus anserinus Zone...",
    url = "https://doi.org/10.1130/mem127-p83",
    doi = "10.1130/mem127-p83",
    openalex = "W2409195358"
}

The internal structure of three representative Ordovican conodont form-species (Drepanodus homocurvatus Lind- strom, Polycaulodus bidentatus Branson and Mehl, and Ptiloconus gracilis (Branson and Mehl)) is investigated using transmission and scanning electron-microscopes. Speci- mens of these species show significant differences, with some similarities, in the character and arrangement of the crystallites that build individual lamellae. In Polycaulodus bidenta- tus, minute spheres are noted that may be analogous to the holes previously described from the white matter of certain lamellar conodonts. The results indicate that the internal structure may eventually prove to be a valuable criterion in taxonomic and phylogenetic conodont studies. sections the specimens were ground down to the level of the growth axis. Traverses across the sections were made using both transmission and scanning methods.

@book{doi105962bhltitle52082,
    author = "Barnes, Christopher R. and Monroe, E. A. and Sass, Daniel B.",
    title = "Preliminary studies of the ultrastructure of selected Ordovician conodonts /",
    year = "1970",
    booktitle = "Royal Ontario Museum eBooks",
    abstract = "The internal structure of three representative Ordovican conodont form-species (Drepanodus homocurvatus Lind- strom, Polycaulodus bidentatus Branson and Mehl, and Ptiloconus gracilis (Branson and Mehl)) is investigated using transmission and scanning electron-microscopes. Speci- mens of these species show significant differences, with some similarities, in the character and arrangement of the crystallites that build individual lamellae. In Polycaulodus bidenta- tus, minute spheres are noted that may be analogous to the holes previously described from the white matter of certain lamellar conodonts. The results indicate that the internal structure may eventually prove to be a valuable criterion in taxonomic and phylogenetic conodont studies. sections the specimens were ground down to the level of the growth axis. Traverses across the sections were made using both transmission and scanning methods.",
    url = "https://doi.org/10.5962/bhl.title.52082",
    doi = "10.5962/bhl.title.52082",
    openalex = "W1515694294"
}

Recognition of four types of skeletal apparatuses of Devonian compound and platform conodonts, which conform in their basic plan to those already established in the Ordovician, Silurian, and Carboniferous, emphasizes the persistence of but a few structural types in the Paleozoic. The vicarious nature primarily of compound but also of platform elements in different multielement associations demonstrates mosaic evolution in Devonian apparatuses and has far-reaching taxonomic implications. Homologies of skeletal elements, for which a system of symbols is introduced, are evident in different apparatus types and show that the relationships of elements have been obscured by the older form taxonomy. Multielement analysis revises the taxonomic scope of the common Devonian genera, Icriodus, Polygnathus, and Ozarkodina. As a consequence of apparatus reconstruction, four new genera are proposed: Parapolygnathus, Cryptotaxis, Delotaxis, and Pedavis.

@article{doi101111j150239311971tb01865x,
    author = "Klapper, Gilbert and Philip, Graeme M.",
    title = "DEVONIAN CONODONT APPARATUSES AND THEIR VICARIOUS SKELETAL ELEMENTS",
    year = "1971",
    journal = "Lethaia",
    abstract = "Recognition of four types of skeletal apparatuses of Devonian compound and platform conodonts, which conform in their basic plan to those already established in the Ordovician, Silurian, and Carboniferous, emphasizes the persistence of but a few structural types in the Paleozoic. The vicarious nature primarily of compound but also of platform elements in different multielement associations demonstrates mosaic evolution in Devonian apparatuses and has far-reaching taxonomic implications. Homologies of skeletal elements, for which a system of symbols is introduced, are evident in different apparatus types and show that the relationships of elements have been obscured by the older form taxonomy. Multielement analysis revises the taxonomic scope of the common Devonian genera, Icriodus, Polygnathus, and Ozarkodina. As a consequence of apparatus reconstruction, four new genera are proposed: Parapolygnathus, Cryptotaxis, Delotaxis, and Pedavis.",
    url = "https://doi.org/10.1111/j.1502-3931.1971.tb01865.x",
    doi = "10.1111/j.1502-3931.1971.tb01865.x",
    openalex = "W2015604245"
}

The ultrastructure of 24 form-species of Ordovician conodonts has been examined with the scanning electron microscope. The conodonts represent two provincial and three subprovincial faunas and include hyaline forms, neurodonts (a subgroup of the hyalines), and cancellate forms (conodonts with white matter). The robust neurodont elements are constructed of cone-in-cone lamellae separated by distinct interlamellar spaces. There is limited fusion between adjacent lamellae and between the long, needle-like crystallites within each lamella. Crystallites become granular in form near the base in some neurodonts. A sheet-like septum bisects the elements longitudinally, but does not pass through the central growth canal. The latter is surrounded by fused lamellae producing a strengthened wall. Minute spheres occur along crystallites in some neurodonts. In the non-neurodont hyaline conodonts, greater fusion occurs between lamellae and between crystallites, and white matter may develop along the central growth canal; no septum or spheres have been noted within this group. Increased fusion is considered to have produced stronger elements capable of acquiring lateral compression, costae, and keels. Cancellate conodonts develop white matter primarily in their cusps and denticles. White matter is finely crystalline with no lamellar structure, but with abundant circular and linear voids. There is no pattern to the occurrence of the holes, but most linear voids are oriented transversely. White matter is formed by secondary transformation from lamellar material; this change is reflected in a transitional zone of incipient white matter, where a reorientation of the hard tissue is evident. Minute spheres occur in white matter; the central growth canal is destroyed and does not penetrate beyond the transition zone. White matter is believed to provide extra strength to the element allowing marked lateral compression and sharp margins. Although separated on structural criteria, these three conodont groups appear to occupy distinct and evolving ecosystems during the Ordovician. Three theories are proposed which, individually or in combination, may indicate the functional advantages conveyed by the development of white matter: (1) that the factors of element weight and phosphate availability were important, (2) that greater strength to cope with variable stresses was achieved, and (3) that white matter was induced by a disruption in vascular supply, possibly resulting from a partial eruption through the secreting tissues.

@incollection{doi101130spe141p1,
    author = "Barnes, Christopher R. and Sass, Daniel B. and Monroe, E. A.",
    title = "Ultrastructure of Some Ordovician Conodonts",
    year = "1972",
    booktitle = "Geological Society of America eBooks",
    abstract = "The ultrastructure of 24 form-species of Ordovician conodonts has been examined with the scanning electron microscope. The conodonts represent two provincial and three subprovincial faunas and include hyaline forms, neurodonts (a subgroup of the hyalines), and cancellate forms (conodonts with white matter). The robust neurodont elements are constructed of cone-in-cone lamellae separated by distinct interlamellar spaces. There is limited fusion between adjacent lamellae and between the long, needle-like crystallites within each lamella. Crystallites become granular in form near the base in some neurodonts. A sheet-like septum bisects the elements longitudinally, but does not pass through the central growth canal. The latter is surrounded by fused lamellae producing a strengthened wall. Minute spheres occur along crystallites in some neurodonts. In the non-neurodont hyaline conodonts, greater fusion occurs between lamellae and between crystallites, and white matter may develop along the central growth canal; no septum or spheres have been noted within this group. Increased fusion is considered to have produced stronger elements capable of acquiring lateral compression, costae, and keels. Cancellate conodonts develop white matter primarily in their cusps and denticles. White matter is finely crystalline with no lamellar structure, but with abundant circular and linear voids. There is no pattern to the occurrence of the holes, but most linear voids are oriented transversely. White matter is formed by secondary transformation from lamellar material; this change is reflected in a transitional zone of incipient white matter, where a reorientation of the hard tissue is evident. Minute spheres occur in white matter; the central growth canal is destroyed and does not penetrate beyond the transition zone. White matter is believed to provide extra strength to the element allowing marked lateral compression and sharp margins. Although separated on structural criteria, these three conodont groups appear to occupy distinct and evolving ecosystems during the Ordovician. Three theories are proposed which, individually or in combination, may indicate the functional advantages conveyed by the development of white matter: (1) that the factors of element weight and phosphate availability were important, (2) that greater strength to cope with variable stresses was achieved, and (3) that white matter was induced by a disruption in vascular supply, possibly resulting from a partial eruption through the secreting tissues.",
    url = "https://doi.org/10.1130/spe141-p1",
    doi = "10.1130/spe141-p1",
    openalex = "W2497400745"
}

The ultrastructure of representative specimens of 11 form species of the conodont genera Panderodus and Belodina, comprising the family Panderodontidae, was investigated using oriented, etched sections examined primarily with the scanning electron microscope.Selected species are of wide stratigraphic and geographic occurrence.Details of the form and pattern of crystallites and lamellae permitted interpretation of the mode of growth of both genera.Critically important is the discovery of radial as well as concentric lamellae.The former, flanking the longitudinal furrow on the inner lateral face and having surface expression as coarse striations, represent a radically different form of element construction not documented, although suspected in other, simple-cone genera.Lamellae constructing the basal rim commonly are restricted to the basal region.Development of white matter is considered to be functionally advantageous by limiting the amount of potential element damage to the cusp and denticle tips.Holes within the lamellar basal filling are considered to be primary.The similarity in ultrastructure between Panderodus and Belodina supports the recent establishment of the family Panderodontidae as a natural, taxonomic unit.

@book{doi105962bhltitle52051,
    author = "Barnes, Christopher R. and Poplawski, Maria Luisa Silvana and Sass, Daniel B.",
    title = "Conodont ultrastructure: the family Panderodontidae /",
    year = "1973",
    booktitle = "Royal Ontario Museum eBooks",
    abstract = "The ultrastructure of representative specimens of 11 form species of the conodont genera Panderodus and Belodina, comprising the family Panderodontidae, was investigated using oriented, etched sections examined primarily with the scanning electron microscope.Selected species are of wide stratigraphic and geographic occurrence.Details of the form and pattern of crystallites and lamellae permitted interpretation of the mode of growth of both genera.Critically important is the discovery of radial as well as concentric lamellae.The former, flanking the longitudinal furrow on the inner lateral face and having surface expression as coarse striations, represent a radically different form of element construction not documented, although suspected in other, simple-cone genera.Lamellae constructing the basal rim commonly are restricted to the basal region.Development of white matter is considered to be functionally advantageous by limiting the amount of potential element damage to the cusp and denticle tips.Holes within the lamellar basal filling are considered to be primary.The similarity in ultrastructure between Panderodus and Belodina supports the recent establishment of the family Panderodontidae as a natural, taxonomic unit.",
    url = "https://doi.org/10.5962/bhl.title.52051",
    doi = "10.5962/bhl.title.52051",
    openalex = "W2506780203"
}

Thirty-four boulders, 30 species, 13 multielement genera (six new species, 19 form-species of 10 form-genera), lower Arenigian fauna (Paracordylodus gracilis) and lower Llanvirnian (Periodon aculeatus), correlation

@article{openalexw2404152402,
    author = "Barnes, Christopher R. and Poplawski, Maria Luisa Silvana",
    title = "Lower and middle Ordovician conodonts from the Mystic Formation, Quebec, Canada",
    year = "1973",
    journal = "Journal of Paleontology",
    abstract = "Thirty-four boulders, 30 species, 13 multielement genera (six new species, 19 form-species of 10 form-genera), lower Arenigian fauna (Paracordylodus gracilis) and lower Llanvirnian (Periodon aculeatus), correlation",
    openalex = "W2404152402"
}

@article{bengtson1976the,
    author = "Bengtson, Stefan",
    title = "The structure of some Middle Cambrian conodonts, and the early evolution of conodont structure and function",
    year = "1976",
    journal = "Lethaia",
    url = "https://doi.org/10.1111/j.1502-3931.1976.tb00966.x",
    doi = "10.1111/j.1502-3931.1976.tb00966.x",
    number = "2",
    openalex = "W2029934195",
    pages = "185-206",
    volume = "9",
    references = "doi101007bf02988965, doi10108011035895409453581, doi101111j1469185x1954tb01518x, doi101111j150239311970tb00834x, doi101127zdgg1111959434, doi101130spe141p1, doi101144gsjgs13130289, doi105962bhltitle52051, doi105962bhltitle52082, openalexw2207565996"
}

Introduction Principles of taxonomy of conodonts The course of the phylogeny Organization of the of branching conodonts Affinities of Conodontophorida The outline of evolution of Conodontophorida Regularities in eyolution of Diagnoses of ne\v taxa List of synonymes References Frequency of conodonts in samples 395:\95 396 398 413 416 417 420 421 42:) 447 454 Abstract. The phylogeny of Ordovician Conodontophorida from the Baltic region is reconstructed and homologization of elements of the natural assemblages is presented. A reconstruction of the apparatus of Spathognathodontidae indicates that it was a bilateral medial organ composed of 14 conodonts with dentides turned inwards. Attempts are made to homologize the tissue of conodonts Panderodontidac with enamel of dermal dentides of lower Ve,tebrata and the basal filling tissue with dentine. A common phenomenon in conodont evolution is the occurrence of morphological gradient within the apparatus. The evolutionary changes are introduced polarly, and successively spread from the most rapidly evolving element on the adjoining ones. Fifty six species and subspecies of Ordovician conodonts are illustrated and their synonymes given. Two new suborders, three genera, seven species and three temporal subspecies are proposed. The phylogeny of Ordovician Conodontophorida from the Baltic region is reconstructed and homologization of elements of the natural assemblages is presented. A reconstruction of the apparatus of Spathognathodontidae indicates that it was a bilateral medial organ composed of 14 conodonts with dentides turned inwards. Attempts are made to homologize the tissue of conodonts Panderodontidac with enamel of dermal dentides of lower Ve,tebrata and the basal filling tissue with dentine. A common phenomenon in conodont evolution is the occurrence of morphological gradient within the apparatus. The evolutionary changes are introduced polarly, and successively spread from the most rapidly evolving element on the adjoining ones. Fifty six species and subspecies of Ordovician conodonts are illustrated and their synonymes given. Two new suborders, three genera, seven species and three temporal subspecies are proposed.

@article{openalexw2732375649,
    author = "Dzik, Jerzy",
    title = "Remarks on the evolution Of Ordovician conodonts",
    year = "1976",
    journal = "Acta Palaeontologica Polonica",
    abstract = "Introduction Principles of taxonomy of conodonts The course of the phylogeny Organization of the of branching conodonts Affinities of Conodontophorida The outline of evolution of Conodontophorida Regularities in eyolution of Diagnoses of ne\v taxa List of synonymes References Frequency of conodonts in samples 395:\95 396 398 413 416 417 420 421 42:) 447 454 Abstract. The phylogeny of Ordovician Conodontophorida from the Baltic region is reconstructed and homologization of elements of the natural assemblages is presented. A reconstruction of the apparatus of Spathognathodontidae indicates that it was a bilateral medial organ composed of 14 conodonts with dentides turned inwards. Attempts are made to homologize the tissue of conodonts Panderodontidac with enamel of dermal dentides of lower Ve,tebrata and the basal filling tissue with dentine. A common phenomenon in conodont evolution is the occurrence of morphological gradient within the apparatus. The evolutionary changes are introduced polarly, and successively spread from the most rapidly evolving element on the adjoining ones. Fifty six species and subspecies of Ordovician conodonts are illustrated and their synonymes given. Two new suborders, three genera, seven species and three temporal subspecies are proposed. The phylogeny of Ordovician Conodontophorida from the Baltic region is reconstructed and homologization of elements of the natural assemblages is presented. A reconstruction of the apparatus of Spathognathodontidae indicates that it was a bilateral medial organ composed of 14 conodonts with dentides turned inwards. Attempts are made to homologize the tissue of conodonts Panderodontidac with enamel of dermal dentides of lower Ve,tebrata and the basal filling tissue with dentine. A common phenomenon in conodont evolution is the occurrence of morphological gradient within the apparatus. The evolutionary changes are introduced polarly, and successively spread from the most rapidly evolving element on the adjoining ones. Fifty six species and subspecies of Ordovician conodonts are illustrated and their synonymes given. Two new suborders, three genera, seven species and three temporal subspecies are proposed.",
    url = "https://openalex.org/W2732375649",
    openalex = "W2732375649",
    references = "bengtson1976the, doi101111j150239311971tb01865x, doi101130mem127p21, doi101130mem127p83, doi105962bhltitle52051, openalexw2268136853, openalexw2404152402, openalexw2600301146, openalexw3162216936, openalexw649519998"
}

Field and laboratory experiments show that color alteration in conodonts is directly related to the depth and duration of burial and the geothermal gradient and correlates with fixed carbon, vitrinite reflectance, palynomorph translucency, and isopach data. Five progressive and irreversible color changes ranging from pale yellow to black are discriminated. Compilation of color alteration index (CAI) maps for limestones of several ages in the Appalachian basin show: (1) a general systematic change from pale yellow (CAI = 1) to black (CAI = 5) from west to east; (2) within a structural belt, older conodonts are darkest; (3) fixed carbon values determined from coals cannot be directly applied to carbonate rocks; (4) several areas of anomalously low CAI values in windows exposing Ordovician rocks within the Blue Ridge-Piedmont terrane. Data show: (1) color alteration of conodonts is time and temperature dependent; (2) the sequence of color change from pale yellow to black found in field collections is the same as that produced by heating alone; (3) upper and lower geologic temperature limits for each CAI determined from a log time versus reciprocal of absolute temperature plot. Water in combination with confined pressure retards color alteration. The color alteration of conodonts ismore » a valuable tool for assessing organic metamorphism because it is a rapid and inexpensive method requiring only standard laboratory techniques and a binocular microscope. The technique provides thermal cutoffs for oil, condensate, and dry gas generation. Conodont color alteration begins near the upper thermal limit for the preservation of many palynomorphs.« less

@article{doi103133pp995,
    author = "Epstein, Anita G. and Epstein, Jack Burton and Harris, Leonard Dorreen",
    title = "Conodont color alteration; an index to organic metamorphism",
    year = "1977",
    journal = "USGS professional paper",
    abstract = "Field and laboratory experiments show that color alteration in conodonts is directly related to the depth and duration of burial and the geothermal gradient and correlates with fixed carbon, vitrinite reflectance, palynomorph translucency, and isopach data. Five progressive and irreversible color changes ranging from pale yellow to black are discriminated. Compilation of color alteration index (CAI) maps for limestones of several ages in the Appalachian basin show: (1) a general systematic change from pale yellow (CAI = 1) to black (CAI = 5) from west to east; (2) within a structural belt, older conodonts are darkest; (3) fixed carbon values determined from coals cannot be directly applied to carbonate rocks; (4) several areas of anomalously low CAI values in windows exposing Ordovician rocks within the Blue Ridge-Piedmont terrane. Data show: (1) color alteration of conodonts is time and temperature dependent; (2) the sequence of color change from pale yellow to black found in field collections is the same as that produced by heating alone; (3) upper and lower geologic temperature limits for each CAI determined from a log time versus reciprocal of absolute temperature plot. Water in combination with confined pressure retards color alteration. The color alteration of conodonts ismore » a valuable tool for assessing organic metamorphism because it is a rapid and inexpensive method requiring only standard laboratory techniques and a binocular microscope. The technique provides thermal cutoffs for oil, condensate, and dry gas generation. Conodont color alteration begins near the upper thermal limit for the preservation of many palynomorphs.« less",
    url = "https://doi.org/10.3133/pp995",
    doi = "10.3133/pp995",
    openalex = "W1547540587",
    references = "doi1010160016703765901018, doi10113000167606197182501tiaapn20co2, doi101130mem127, doi101130spe153, doi101130spe153p1, doi101130spe153p31, doi101130spe153p53, doi10130683d91f0616c711d78645000102c1865d, openalexw1826625507, openalexw2613102951"
}

@misc{briggs1983the1,
    author = "Briggs, D. E. G. and Clarkson, E. N. K. and Aldridge, R. J",
    title = "The conodont animal",
    year = "1983",
    howpublished = "Lethaia, v. 16, p. 1-14",
    note = "talkorigins\_source = {true}; raw\_reference = {Briggs, D. E. G., Clarkson, E. N. K., and Aldridge, R. J., 1983, The conodont animal: Lethaia, v. 16, p. 1-14.}"
}

@article{doi101111j150239311983tb01139x,
    author = "Briggs, Derek E. G. and Clarkson, Euan N. K. and Aldridge, Richard J.",
    title = "The conodont animal",
    year = "1983",
    journal = "Lethaia",
    url = "https://doi.org/10.1111/j.1502-3931.1983.tb01139.x",
    doi = "10.1111/j.1502-3931.1983.tb01139.x",
    openalex = "W4236104903",
    references = "doi101144pygs313227"
}

A unique specimen of a small, elongate, soft-bodied animal from the Lower Carboniferous of the Edinburgh district, Scotland, is described. The head expands anteriorly into two lobate structures flanking a central lumen; behind this lies a conodont apparatus, apparently in situ, consisting of an aligned set of ramiform elements followed by a pair of ozarkodiniform elements and one of platform elements. From the morphology of the platform elements the animal has been identified as Clydagnathus? cf. cavusformis. Repeated structures which may represent segments are evident in the posterior part of the trunk, which bears a posterior and a caudal fin, each supported by rays. The animal shows similarities to both chordates and chactognaths, but the evidence supports its assignment to a separate phylum, the Conodonta. The function of the conodonts remains equivocal, but it seems more likely that they served as teeth than as internal supports.

@article{doi101111j150239311983tb01993x,
    author = "Briggs, Derek E. G. and Clarkson, Euan N. K. and Aldridge, Richard J.",
    title = "The conodont animal",
    year = "1983",
    journal = "Lethaia",
    abstract = "A unique specimen of a small, elongate, soft-bodied animal from the Lower Carboniferous of the Edinburgh district, Scotland, is described. The head expands anteriorly into two lobate structures flanking a central lumen; behind this lies a conodont apparatus, apparently in situ, consisting of an aligned set of ramiform elements followed by a pair of ozarkodiniform elements and one of platform elements. From the morphology of the platform elements the animal has been identified as Clydagnathus? cf. cavusformis. Repeated structures which may represent segments are evident in the posterior part of the trunk, which bears a posterior and a caudal fin, each supported by rays. The animal shows similarities to both chordates and chactognaths, but the evidence supports its assignment to a separate phylum, the Conodonta. The function of the conodonts remains equivocal, but it seems more likely that they served as teeth than as internal supports.",
    url = "https://doi.org/10.1111/j.1502-3931.1983.tb01993.x",
    doi = "10.1111/j.1502-3931.1983.tb01993.x",
    openalex = "W2025438143",
    references = "bengtson1976the, doi1010160012825277901490, doi101016s0065288108604393, doi101126science16238591265, doi101144pygs313227, doi105962bhltitle5167, doi105962p310413, openalexw2598746693, openalexw2753772898, openalexw648113948"
}

The transgressive Table Head Formation has been described and sampled from eight localities on Great Northern Peninsula, western Newfoundland. The Table Head sediments all along the westcoast of Newfoundland are comparable, but the thickness of the different units varies considerably. The detailed investigation of the rocks revealed that carbonate accumulation was interrupted by 'catastrophic' downwarps of the shelf. These may be related to the emplacement of the allochthons. Two Phylozones and four local assemblage-zones are defined. The phylozones are based on phylogenetically related species of Histiodella. The species from the basal lower Table Head belong to Midcontinent Fauna 4. The North Atlantic Province conodonts from the middle Table Head correlate with Eoplacognathus suecicus Zone and E. suecicus-P. sulcatus Subzone of Scandinavia. The Table Head strata accumulated in lagoonal, shelf (inner-outer) and slope environments. The lateral distribution of conodonts has been directly related to these depositional environments, and a sequence of three biofacies and three subbiofacies is introduced. The conodont fauna is described in multielement taxonomy, and a suprageneric classification is applied. Thirty-five genera and 70 species are described of which two genera and 20 species are new. The Superfamily Panderodontacea Lindström is subdivided into the families Acanthodontidae, Panderodontidae, and the new family Cornuodontidae.

@book{doi101826182000954871984,
    author = "Stouge, Svend",
    title = "Conodonts of the Middle Ordovician Table Head Formation, western Newfoundland",
    year = "1984",
    booktitle = "Fossils and strata",
    abstract = "The transgressive Table Head Formation has been described and sampled from eight localities on Great Northern Peninsula, western Newfoundland. The Table Head sediments all along the westcoast of Newfoundland are comparable, but the thickness of the different units varies considerably. The detailed investigation of the rocks revealed that carbonate accumulation was interrupted by 'catastrophic' downwarps of the shelf. These may be related to the emplacement of the allochthons. Two Phylozones and four local assemblage-zones are defined. The phylozones are based on phylogenetically related species of Histiodella. The species from the basal lower Table Head belong to Midcontinent Fauna 4. The North Atlantic Province conodonts from the middle Table Head correlate with Eoplacognathus suecicus Zone and E. suecicus-P. sulcatus Subzone of Scandinavia. The Table Head strata accumulated in lagoonal, shelf (inner-outer) and slope environments. The lateral distribution of conodonts has been directly related to these depositional environments, and a sequence of three biofacies and three subbiofacies is introduced. The conodont fauna is described in multielement taxonomy, and a suprageneric classification is applied. Thirty-five genera and 70 species are described of which two genera and 20 species are new. The Superfamily Panderodontacea Lindström is subdivided into the families Acanthodontidae, Panderodontidae, and the new family Cornuodontidae.",
    url = "https://doi.org/10.18261/8200095487-1984",
    doi = "10.18261/8200095487-1984",
    openalex = "W2982637783",
    references = "openalexw2207565996, openalexw2296057071, openalexw2732375649"
}

The Polygnathus biofacies characterizes the Frasnian sequence in the Hay River, Trout River, and adjacent areas of the southwestern Northwest Territories. The sequence spans almost the entire Frasnian. Only at certain levels are there minor incursions of species of Palmatolepis, Ancyrodella, and Ancyrognathus that elsewhere characterize the Palmatolepis biofacies, on which the conodont zonation of the Frasnian is based. The problem of intercorrelation of the two biofacies has not been resolved by this study and correlations with the Palmatolepis biofacies are approx- imations: the sampled Hay River Formation extends from the Middle or Upper asymmetricus Zone up to the A. triangularis or Lower gigas Zone; part of the Twin Falls Formation is in the Lower gigas Zone; the sampled uppermost Fort Simpson Shale, Redknife and Kakisa formations appear to correlate with the Upper gigas Zone. Although the sequence has only been sampled in a preliminary way, a substantial number of new species have been recognized, probably because there have been few published studies of the Frasnian Polygnathus biofacies. Newly described species are Ozarkodina dissimilis, 0. postera,

@article{openalexw2261074785,
    author = "Klapper, Gilbert and Lane, H. Richard",
    title = "Upper Devonian (Frasnian) conodonts of the Polygnathus biofacies, N.W.T., Canada",
    year = "1985",
    journal = "Journal of Paleontology",
    abstract = "The Polygnathus biofacies characterizes the Frasnian sequence in the Hay River, Trout River, and adjacent areas of the southwestern Northwest Territories. The sequence spans almost the entire Frasnian. Only at certain levels are there minor incursions of species of Palmatolepis, Ancyrodella, and Ancyrognathus that elsewhere characterize the Palmatolepis biofacies, on which the conodont zonation of the Frasnian is based. The problem of intercorrelation of the two biofacies has not been resolved by this study and correlations with the Palmatolepis biofacies are approx- imations: the sampled Hay River Formation extends from the Middle or Upper asymmetricus Zone up to the A. triangularis or Lower gigas Zone; part of the Twin Falls Formation is in the Lower gigas Zone; the sampled uppermost Fort Simpson Shale, Redknife and Kakisa formations appear to correlate with the Upper gigas Zone. Although the sequence has only been sampled in a preliminary way, a substantial number of new species have been recognized, probably because there have been few published studies of the Frasnian Polygnathus biofacies. Newly described species are Ozarkodina dissimilis, 0. postera,",
    openalex = "W2261074785",
    references = "openalexw2598746693"
}

Three new specimens which preserve the soft parts of conodonts are described from the Lower Carboniferous of Granton, Edinburgh. The animal was apparently laterally flattened in life and the somites were V-shaped. The nature of the preserved axial lines is equivocal; some may represent the walls of the gut. The elements of one of the new specimens show that it does not belong to Clydagnathus, to which the other soft-bodied specimen from Granton was tentatively assigned. The possibility of a relationship between the euconodonts and the Chaetognatha is discounted. Nor do the conodonts constitute a phylum, but are a separate group of primitive jawless craniates.

@article{doi101111j150239311986tb00741x,
    author = "Aldridge, Richard J. and Briggs, Derek E. G. and Clarkson, Euan N. K. and Smith, M. Paul",
    title = "The affinities of conodonts—new evidence from the Carboniferous of Edinburgh, Scotland",
    year = "1986",
    journal = "Lethaia",
    abstract = "Three new specimens which preserve the soft parts of conodonts are described from the Lower Carboniferous of Granton, Edinburgh. The animal was apparently laterally flattened in life and the somites were V-shaped. The nature of the preserved axial lines is equivocal; some may represent the walls of the gut. The elements of one of the new specimens show that it does not belong to Clydagnathus, to which the other soft-bodied specimen from Granton was tentatively assigned. The possibility of a relationship between the euconodonts and the Chaetognatha is discounted. Nor do the conodonts constitute a phylum, but are a separate group of primitive jawless craniates.",
    url = "https://doi.org/10.1111/j.1502-3931.1986.tb00741.x",
    doi = "10.1111/j.1502-3931.1986.tb00741.x",
    openalex = "W2050771029",
    references = "doi1010160031018283900962, doi10108002724634198110011886, doi10108002724634198310011943, doi10108003115517708527770, doi10108011035898809452656, doi101111j109636421985tb01802x, doi101111j150239311983tb01993x, doi10182618200067378198301, openalexw2732375649, openalexw587905045"
}

@article{doi10108011035898809452656,
    title = "Palaeobiology of conodonts",
    year = "1988",
    journal = "Geologiska Föreningen i Stockholm Förhandlingar",
    url = "https://doi.org/10.1080/11035898809452656",
    doi = "10.1080/11035898809452656",
    openalex = "W1488474672"
}

From histological investigations into the microstructure of conodont elements, a number of tissue types characteristic of the phosphatic skeleton of vertebrates have been identified. These include cellular bone, two forms of hypermineralized enamel homologs, and globular calcified cartilage. The presence of cellular bone in conodont elements provides unequivocal evidence for their vertebrate affinities. Furthermore, the identification of vertebrate hard tissues in the oral elements of conodonts extends the earliest occurrence of vertebrate hard tissues back by around 40 million years, from the Middle Ordovician (475 million years ago) to the Late Cambrian (515 million years ago).

@article{doi101126science1598573,
    author = "Sansom, IJ and Smith, M. Paul and Armstrong, H. A. and Smith, Mm",
    title = "Presence of the Earliest Vertebrate Hard Tissue in Conodonts",
    year = "1992",
    journal = "Science",
    abstract = "From histological investigations into the microstructure of conodont elements, a number of tissue types characteristic of the phosphatic skeleton of vertebrates have been identified. These include cellular bone, two forms of hypermineralized enamel homologs, and globular calcified cartilage. The presence of cellular bone in conodont elements provides unequivocal evidence for their vertebrate affinities. Furthermore, the identification of vertebrate hard tissues in the oral elements of conodonts extends the earliest occurrence of vertebrate hard tissues back by around 40 million years, from the Middle Ordovician (475 million years ago) to the Late Cambrian (515 million years ago).",
    url = "https://doi.org/10.1126/science.1598573",
    doi = "10.1126/science.1598573",
    openalex = "W1991633942",
    references = "doi10108002724634198110011886, doi101111j146364091980tb00660x, doi101111j1469185x1990tb01427x, doi101111j150239311983tb01993x, doi101111j150239311986tb00741x, doi101111j150239311990tb01369x, doi1023071220820, doi1023071483846, doi105860choice266278, openalexw587905045"
}

Abstract Six sections through lower Ordovician shale and limestone at Hunneberg have been sampled for conodonts. Forty-nine limestone horizons and 34 shale surface samples yielded over 40000 conodont elements. The degree of biostratigraphic resolution permitted further subdivision of the post-Tremadoc Paroistodus proteus Zone into four successive intervals. Preliminary studies of coeval rocks in other areas of Sweden show that this subdivision applies elsewhere as well. Comparison with published sections from, for example, Newfoundland, Estonia and Kazakhstan indicates that the fourfold subdivision of the P. proteus Zone proposed here could significantly increase the correlation accuracy, even internationally, within this critical part of the Ordovician. Graptolites and trilobites found together with the conodonts at Hunneberg indicated that the new subdivision could help to correlate biostratigraphic units based on these fossil groups. Thus the two lower intervals of the P. proteus Zone correspond to the M. (E.) armata trilobite Zone, and the upper two are approximately equal to the M. (V.) planilimbata Zone. The base of the T. phyllograptoides graptolite Zone at Hunneberg lies close to the boundary between the upper middle and uppermost intervals of the P. proteus Zone, but the graptolitic chronozonal boundary may be lower. The overlying Prioniodus elegans Zone is mainly represented by graptolitic shale at Hunneberg, but conodont faunas have been found in it, and co-occurrences of conodonts and graptolites have been noted.

@article{doi101017s0016756800009870,
    author = "Löfgren, Anita",
    title = "Conodonts from the lower Ordovician at Hunneberg, south-central Sweden",
    year = "1993",
    journal = "Geological Magazine",
    abstract = "Abstract Six sections through lower Ordovician shale and limestone at Hunneberg have been sampled for conodonts. Forty-nine limestone horizons and 34 shale surface samples yielded over 40000 conodont elements. The degree of biostratigraphic resolution permitted further subdivision of the post-Tremadoc Paroistodus proteus Zone into four successive intervals. Preliminary studies of coeval rocks in other areas of Sweden show that this subdivision applies elsewhere as well. Comparison with published sections from, for example, Newfoundland, Estonia and Kazakhstan indicates that the fourfold subdivision of the P. proteus Zone proposed here could significantly increase the correlation accuracy, even internationally, within this critical part of the Ordovician. Graptolites and trilobites found together with the conodonts at Hunneberg indicated that the new subdivision could help to correlate biostratigraphic units based on these fossil groups. Thus the two lower intervals of the P. proteus Zone correspond to the M. (E.) armata trilobite Zone, and the upper two are approximately equal to the M. (V.) planilimbata Zone. The base of the T. phyllograptoides graptolite Zone at Hunneberg lies close to the boundary between the upper middle and uppermost intervals of the P. proteus Zone, but the graptolitic chronozonal boundary may be lower. The overlying Prioniodus elegans Zone is mainly represented by graptolitic shale at Hunneberg, but conodont faunas have been found in it, and co-occurrences of conodonts and graptolites have been noted.",
    url = "https://doi.org/10.1017/s0016756800009870",
    doi = "10.1017/s0016756800009870",
    openalex = "W2165506952",
    references = "doi101130mem127p21, lindström1957two"
}

Multielement taxonomy and shape analysis have led to substantial revisions in the taxonomic concepts of 13 Frasnian species of Palmatolepis, which previously have been based largely on visual discrimination of the Pa elements. Septimembrate apparatuses have been recognized in three species and diagnostic Pb elements are associated with the Pa elements of eight others. The multielement reconstructions thus derived provide the a priori classification that is tested by the canonical variate analysis of the outlines of the Pa elements. The outlines are digitized from a TV image and quantified by calculating mean tangent angles within a specified number of intervals between landmarks. The mean tangent angles for each interval are the variables used in the canonical variate analysis. In a series of comparisons limited to three species each, all 13 species separate into isolated clusters that are completely congruent with the a priori groups based, with two exceptions, on multielement taxonomy. Thus, shape analysis provides a rigorous separation of closely similar species that have been difficult to distinguish by visual discrimination of the Pa elements. Shape analysis is treated herein as an integral part of the systematic descriptions. Newly described species are P. bohemica, P. boogaardi, P. luscarensis, and P. muelleri. The new taxonomic concepts lead to significant revisions in the biostratigraphic ranges of a number of species of Palmatolepis involved in the zonation and graphic correlation of the Frasnian Stage.

@article{doi101017s0022336000062168,
    author = "Klapper, Gilbert and Foster, C. T.",
    title = "Shape Analysis of Frasnian Species of the Late Devonian Conodont Genus Palmatolepis",
    year = "1993",
    journal = "Journal of Paleontology",
    abstract = "Multielement taxonomy and shape analysis have led to substantial revisions in the taxonomic concepts of 13 Frasnian species of Palmatolepis, which previously have been based largely on visual discrimination of the Pa elements. Septimembrate apparatuses have been recognized in three species and diagnostic Pb elements are associated with the Pa elements of eight others. The multielement reconstructions thus derived provide the a priori classification that is tested by the canonical variate analysis of the outlines of the Pa elements. The outlines are digitized from a TV image and quantified by calculating mean tangent angles within a specified number of intervals between landmarks. The mean tangent angles for each interval are the variables used in the canonical variate analysis. In a series of comparisons limited to three species each, all 13 species separate into isolated clusters that are completely congruent with the a priori groups based, with two exceptions, on multielement taxonomy. Thus, shape analysis provides a rigorous separation of closely similar species that have been difficult to distinguish by visual discrimination of the Pa elements. Shape analysis is treated herein as an integral part of the systematic descriptions. Newly described species are P. bohemica, P. boogaardi, P. luscarensis, and P. muelleri. The new taxonomic concepts lead to significant revisions in the biostratigraphic ranges of a number of species of Palmatolepis involved in the zonation and graphic correlation of the Frasnian Stage.",
    url = "https://doi.org/10.1017/s0022336000062168",
    doi = "10.1017/s0022336000062168",
    openalex = "W2945864912",
    references = "openalexw2598746693"
}

Abstract Specimens from the Carboniferous Granton shrimp bed of Edinburgh, Scotland, provide the most complete record of conodont anatomy. Ten specimens are now known, six of which are previously undescribed, and form the basis of a new description and restoration of the conodont animal. The feeding apparatus is present in eight of the specimens; all but two of these can be assigned to Clydagnathus on the basis of the elements. A different genus and species is represented by the other two. The soft tissue morphology of all the specimens is similar. The Granton animals are elongate, 21-55 mm in preserved length with a short head, a trunk with Vshaped myomeres, and a ray-supported caudal fin. The head is characterized by two lobate structures, which are interpreted as hollow sclerotic cartilages indicating the position of large eyes. One specimen preserves traces of possible otic (auditory) capsules and branchial structures. Ventral and immediately posterior to the eyes lies the feeding apparatus, with the ramiform elements at the anterior end. There is no evidence of tissue surrounding this apparatus, indicating incomplete preservation of ventral soft parts, at least at the anterior end of the specimens.

@article{doi101098rstb19930082,
    author = "Aldridge, Richard J. and Briggs, Derek E. G. and Smith, M. Paul and Clarkson, Euan N. K. and Clark, Neil D. L.",
    title = "The anatomy of conodonts",
    year = "1993",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "Abstract Specimens from the Carboniferous Granton shrimp bed of Edinburgh, Scotland, provide the most complete record of conodont anatomy. Ten specimens are now known, six of which are previously undescribed, and form the basis of a new description and restoration of the conodont animal. The feeding apparatus is present in eight of the specimens; all but two of these can be assigned to Clydagnathus on the basis of the elements. A different genus and species is represented by the other two. The soft tissue morphology of all the specimens is similar. The Granton animals are elongate, 21-55 mm in preserved length with a short head, a trunk with Vshaped myomeres, and a ray-supported caudal fin. The head is characterized by two lobate structures, which are interpreted as hollow sclerotic cartilages indicating the position of large eyes. One specimen preserves traces of possible otic (auditory) capsules and branchial structures. Ventral and immediately posterior to the eyes lies the feeding apparatus, with the ramiform elements at the anterior end. There is no evidence of tissue surrounding this apparatus, indicating incomplete preservation of ventral soft parts, at least at the anterior end of the specimens.",
    url = "https://doi.org/10.1098/rstb.1993.0082",
    doi = "10.1098/rstb.1993.0082",
    openalex = "W2089723817",
    references = "doi10100797814615696887, doi1010079789401579261, doi101016s0070215321x00026, doi101038361129a0, doi101086413055, doi101111j1469185x1990tb01427x, doi101126science2204594268, doi101242dev103supplement155, doi105860choice266278, doi105962p310413, müller1991upper, openalexw2732375649, vandenboogaard1992upper"
}

@article{doi101038374798a0,
    author = "Purnell, Mark A.",
    title = "Microwear on conodont elements and macrophagy in the first vertebrates",
    year = "1995",
    journal = "Nature",
    url = "https://doi.org/10.1038/374798a0",
    doi = "10.1038/374798a0",
    openalex = "W2094164895",
    references = "doi101002ajpa1330590208, doi101017s0022336000032145, doi10108011035898809452656, doi101098rstb19930082, doi101111j150239311990tb01369x, doi101126science2204594268, doi1023073515582, openalexw1596319114, openalexw1599677799, openalexw1964182146, openalexw1994482665"
}

@article{doi101038374800a0,
    author = "Gabbott, Sarah E. and Aldridge, Richard J. and Theron, Johannes N.",
    title = "A giant conodont with preserved muscle tissue from the Upper Ordovician of South Africa",
    year = "1995",
    journal = "Nature",
    url = "https://doi.org/10.1038/374800a0",
    doi = "10.1038/374800a0",
    openalex = "W1996235253"
}

Abstract The new standard conodont zonation includes, in succession from below: Lower Ps. bicornis Zone, Upper Ps. bicornis Zone, Lower P. procerus Zone, Upper P. procerus Zone, Lower K. ranuliformis Zone, Upper K. ranuliformis Zone, 0. s. rhenana Zone, Lower K. walliseri Zone, Middle K. walliseri Zone, K. patula Zone, uppermost K. walliseri range, post K. walliseri interregnum, K. o. ortus Zone and 0. s. sagitta Zone. Lower boundaries for each zone are defined or redefined. A less detailed biostratigraphic nomenclature at the superzone level is suggested for use where collections are inadequate: The Pterospathodus Zonal group, the Upper Pterospathodus Zonal group, the P. amorphognathoides Zonal group, the Ps. bicornis Superzone, the P. procerus Superzone, the K. ranuliformis Superzone, the O. s. rhenana Superzone, the K. walliseri Zonal group, the Upper K. walliseri Superzone and the K. o. ortus Superzone. These partly overlap and can be used according to the taxa present. The proposed zonation is applied to most known conodont sequences. The taxonomic concept of the taxa used is discussed; new taxa include Nudibelodina sensitiva, Ozarkodina paraconfluens and O. martinssoni. The species name Ozarkodina ortus is a senior synonym of Kockelella absidata.

@article{doi101017s0263593300006854,
    author = "Jeppsson, Lennart",
    title = "A new latest Telychian, Sheinwoodian and Early Homerian (Early Silurian) Standard Conodont Zonation",
    year = "1997",
    journal = "Transactions of the Royal Society of Edinburgh Earth Sciences",
    abstract = "Abstract The new standard conodont zonation includes, in succession from below: Lower Ps. bicornis Zone, Upper Ps. bicornis Zone, Lower P. procerus Zone, Upper P. procerus Zone, Lower K. ranuliformis Zone, Upper K. ranuliformis Zone, 0. s. rhenana Zone, Lower K. walliseri Zone, Middle K. walliseri Zone, K. patula Zone, uppermost K. walliseri range, post K. walliseri interregnum, K. o. ortus Zone and 0. s. sagitta Zone. Lower boundaries for each zone are defined or redefined. A less detailed biostratigraphic nomenclature at the superzone level is suggested for use where collections are inadequate: The Pterospathodus Zonal group, the Upper Pterospathodus Zonal group, the P. amorphognathoides Zonal group, the Ps. bicornis Superzone, the P. procerus Superzone, the K. ranuliformis Superzone, the O. s. rhenana Superzone, the K. walliseri Zonal group, the Upper K. walliseri Superzone and the K. o. ortus Superzone. These partly overlap and can be used according to the taxa present. The proposed zonation is applied to most known conodont sequences. The taxonomic concept of the taxa used is discussed; new taxa include Nudibelodina sensitiva, Ozarkodina paraconfluens and O. martinssoni. The species name Ozarkodina ortus is a senior synonym of Kockelella absidata.",
    url = "https://doi.org/10.1017/s0263593300006854",
    doi = "10.1017/s0263593300006854",
    openalex = "W2053896396"
}

Ozarkodinid conodonts were one of the most successful groups of agnathan vertebrates. Only the oropharyngeal feeding apparatus of conodonts was mineralized, and the skeletal elements were generally disarticulated on the death and decay of the body. Occasionally, however, they were preserved in association as ‘natural assemblages’, fossilized in situ after post–mortem collapse of the apparatus. From analysis of element arrangement in natural assemblages of Idiognathodus from the Pennsylvanian of Illinois we have produced a precise scale model of the feeding apparatus of ozarkodinid conodonts. At the front lay an axial Sa element, flanked by two groups of four close-set elongate Sb and Sc elements which were inclined obliquely inwards and forwards; above these elements lay a pair of arched and inward pointing M elements. Behind the S-M array lay transversely oriented and bilaterally opposed Pb and Pa elements. Our model sheds new light on food acquisition in conodonts. We propose that the anterior S and M elements of ozarkodinid conodonts were attached to cartilaginous plates. In order for the animal to feed, these plates were first everted, and then drawn back and upward over the anterior edge of an underlying cartilage. These movements produced a highly effective grasping action, the cusps and denticles of the elements converging to grab and impale any food item that lay anterior to the open array. According to this hypothesis, the anterior part of the conodont apparatus is comparable to, and possibly homologous with, the lingual apparatus of extant agnathans; the elements themselves, however, have no direct homologues.

@article{doi101098rstb19970141,
    author = "Purnell, Mark A. and Donoghue, Philip C. J.",
    title = "Architecture and functional morphology of the skeletal apparatus of ozarkodinid conodonts",
    year = "1997",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "Ozarkodinid conodonts were one of the most successful groups of agnathan vertebrates. Only the oropharyngeal feeding apparatus of conodonts was mineralized, and the skeletal elements were generally disarticulated on the death and decay of the body. Occasionally, however, they were preserved in association as ‘natural assemblages’, fossilized in situ after post–mortem collapse of the apparatus. From analysis of element arrangement in natural assemblages of Idiognathodus from the Pennsylvanian of Illinois we have produced a precise scale model of the feeding apparatus of ozarkodinid conodonts. At the front lay an axial Sa element, flanked by two groups of four close-set elongate Sb and Sc elements which were inclined obliquely inwards and forwards; above these elements lay a pair of arched and inward pointing M elements. Behind the S-M array lay transversely oriented and bilaterally opposed Pb and Pa elements. Our model sheds new light on food acquisition in conodonts. We propose that the anterior S and M elements of ozarkodinid conodonts were attached to cartilaginous plates. In order for the animal to feed, these plates were first everted, and then drawn back and upward over the anterior edge of an underlying cartilage. These movements produced a highly effective grasping action, the cusps and denticles of the elements converging to grab and impale any food item that lay anterior to the open array. According to this hypothesis, the anterior part of the conodont apparatus is comparable to, and possibly homologous with, the lingual apparatus of extant agnathans; the elements themselves, however, have no direct homologues.",
    url = "https://doi.org/10.1098/rstb.1997.0141",
    doi = "10.1098/rstb.1997.0141",
    openalex = "W2105088765",
    references = "openalexw2601695287, openalexw2732375649"
}

Abstract Conodont element function and feeding mechanisms are of considerable paleobiological importance, yet many details remain poorly understood and speculative. Analysis based on morphology, physical juxtaposition, and patterns of surface damage and microwear on pairs of Pa elements from individuals of Idiognathodus indicates that these elements crushed food by rotational closure, which brought the oral surfaces into complex interpenetrative occlusion. Other molariform conodont elements also functioned in this manner. Occlusion of this complexity is unique among nonmammalian vertebrates, and is all the more surprising given that conodonts lacked jaws. In addition to enhanced understanding of food processing in conodonts, our analysis suggests that many details of conodont Pa element morphology, which underpin taxonomy and biostratigraphy, can now be interpreted in a paleobiological, functional context.

@article{doi1016660094837319990250058moic23co2,
    author = "Donoghue, Philip C. J. and Purnell, Mark A.",
    title = "Mammal-like occlusion in conodonts",
    year = "1999",
    journal = "Paleobiology",
    abstract = "Abstract Conodont element function and feeding mechanisms are of considerable paleobiological importance, yet many details remain poorly understood and speculative. Analysis based on morphology, physical juxtaposition, and patterns of surface damage and microwear on pairs of Pa elements from individuals of Idiognathodus indicates that these elements crushed food by rotational closure, which brought the oral surfaces into complex interpenetrative occlusion. Other molariform conodont elements also functioned in this manner. Occlusion of this complexity is unique among nonmammalian vertebrates, and is all the more surprising given that conodonts lacked jaws. In addition to enhanced understanding of food processing in conodonts, our analysis suggests that many details of conodont Pa element morphology, which underpin taxonomy and biostratigraphy, can now be interpreted in a paleobiological, functional context.",
    url = "https://doi.org/10.1666/0094-8373(1999)025<0058:moic>2.3.co;2",
    doi = "10.1666/0094-8373(1999)025<0058:moic>2.3.co;2",
    openalex = "W2132811324",
    references = "openalexw2598746693, openalexw2601695287"
}

The present study reports upon the conodont fauna of the Upper Serpukhovian through Lower Moscovian of the Donets Basin, Ukraine. Three new species are described: Declinognathodus? pseudolateralis, Idiognathodus praedelicatus and Idiognathoides postsulcatus. The relatively continuous, rhythmic succession of shales, siltstones and sandstones, with limestone interlayers and coal seams contains a wide variety of fossils: foraminifers, conodonts, brachiopods, ostracods, corals, gastropods, ammonoids, crinoids, bivalves, bryozoans, plant remains etc. It is therefore the key or standard section for interregional and intercontinental correlations. Additionally, the Bashkirian Stage is significant in Late Carboniferous conodont evolution as during this interval all of the Late Carboniferous and Early Permian genera originated. \n At the Mid-Carboniferous boundary almost all of the Early Carboniferous conodont genera became extinct. The descendants of the Early Carboniferous genus Gnathodus appeared. The species of Declinognathodus and Idiognathoides, which derived from the Gn. bilineatus s.l.-Gn. postbilineatus lineage, radiated and were widespread throughout the Bashkirian and Early Moscovian. Neognathodus species, which possibly originated from G. girtyi s.l., appeared a little later and played a subordinate role in the Donets Basin. In the middle of the Bashkirian, or a little earlier, Idiognathodus and then Streptognathodus joined the above-mentioned genera. They dominated from Moscovian through Early Permian times. \n The Bashkirian conodonts in the Donets succession are diverse, but Idiognathoides species prevail. As Idiognathoides seems to have had a broad environmental adaptibility it may have a correlative value together with other important Bashkirian conodonts, and thus increase the potential of the Donets Bashkirian section as a bridge for the correlation between Western and Eastern Europe, America and Asia. \n Ten conodont zones are distinguished here as follows: 1) Gn. bilineatus bollandensis-Ad. unicornis, 2) Gn. postbilineatus, 3) Decl. noduliferus, 4) Id. sinuatus-Id. sulcatus, 5) I. sinuosus-Id. sulcatus parvus, 6) Str. expansus, 7) Id. tuberculatus-Id. fossatus, 8) Decl. marginodosus, 9) Decl. donetzianus, and 10) Str. transitivus. The first two zones with the subjacent Lochriea ziegleri Zone comprise the Serpukhovian, the next six zones, starting with the Decl. noduliferus Zone, correspond to the Bashkirian, and the last two of those belong to the Early Moscovian, although the conodonts of the Decl. donetzianus Zone resemble the latest stage of the Bashkirian conodont evolution. \n The lower boundary of the Bashkirian Stage coincides with the Mid-Carboniferous Boundary as defined by the appearance of Decl. noduliferus s.l. (Lane & Manger, 1985; Nemirovskaya & Nigmadganov, 1994; pers. commun. of Rich Lane, August, 1998) and is drawn at the base of the limestone D58 (Nemirovskaya et al., 1990). \nThe upper boundary of the Bashkirian in the Donets Basin is drawn at the base of limestone K3 of the C25(K) Suite. This suite (formation) contains the same conodont association as the Vereisky Horizon of the Moscow Syneclise and the Asatausky and Vereisky horizons of the Bashkirian stratotype, South Urals. It might probably be correlated with the Aegiranum Marine Band (basal Bolsovian or basal Westphalian C) of Western Europe. The uppermost Bashkirian/Lower Moscovian deposits of the Donets Basin seem to correspond to the Atokan of North America.

@article{openalexw2151657247,
    author = "Nemyrovska, Tamara I.",
    title = "Bashkirian conodonts of the Donets Basin, Ukraine",
    year = "1999",
    journal = "The Digital Academic Repository of Naturalis Biodiversity Center (Naturalis Biodiversity Center)",
    abstract = "The present study reports upon the conodont fauna of the Upper Serpukhovian through Lower Moscovian of the Donets Basin, Ukraine. Three new species are described: Declinognathodus? pseudolateralis, Idiognathodus praedelicatus and Idiognathoides postsulcatus. The relatively continuous, rhythmic succession of shales, siltstones and sandstones, with limestone interlayers and coal seams contains a wide variety of fossils: foraminifers, conodonts, brachiopods, ostracods, corals, gastropods, ammonoids, crinoids, bivalves, bryozoans, plant remains etc. It is therefore the key or standard section for interregional and intercontinental correlations. Additionally, the Bashkirian Stage is significant in Late Carboniferous conodont evolution as during this interval all of the Late Carboniferous and Early Permian genera originated. \n At the Mid-Carboniferous boundary almost all of the Early Carboniferous conodont genera became extinct. The descendants of the Early Carboniferous genus Gnathodus appeared. The species of Declinognathodus and Idiognathoides, which derived from the Gn. bilineatus s.l.-Gn. postbilineatus lineage, radiated and were widespread throughout the Bashkirian and Early Moscovian. Neognathodus species, which possibly originated from G. girtyi s.l., appeared a little later and played a subordinate role in the Donets Basin. In the middle of the Bashkirian, or a little earlier, Idiognathodus and then Streptognathodus joined the above-mentioned genera. They dominated from Moscovian through Early Permian times. \n The Bashkirian conodonts in the Donets succession are diverse, but Idiognathoides species prevail. As Idiognathoides seems to have had a broad environmental adaptibility it may have a correlative value together with other important Bashkirian conodonts, and thus increase the potential of the Donets Bashkirian section as a bridge for the correlation between Western and Eastern Europe, America and Asia. \n Ten conodont zones are distinguished here as follows: 1) Gn. bilineatus bollandensis-Ad. unicornis, 2) Gn. postbilineatus, 3) Decl. noduliferus, 4) Id. sinuatus-Id. sulcatus, 5) I. sinuosus-Id. sulcatus parvus, 6) Str. expansus, 7) Id. tuberculatus-Id. fossatus, 8) Decl. marginodosus, 9) Decl. donetzianus, and 10) Str. transitivus. The first two zones with the subjacent Lochriea ziegleri Zone comprise the Serpukhovian, the next six zones, starting with the Decl. noduliferus Zone, correspond to the Bashkirian, and the last two of those belong to the Early Moscovian, although the conodonts of the Decl. donetzianus Zone resemble the latest stage of the Bashkirian conodont evolution. \n The lower boundary of the Bashkirian Stage coincides with the Mid-Carboniferous Boundary as defined by the appearance of Decl. noduliferus s.l. (Lane \& Manger, 1985; Nemirovskaya \& Nigmadganov, 1994; pers. commun. of Rich Lane, August, 1998) and is drawn at the base of the limestone D58 (Nemirovskaya et al., 1990). \nThe upper boundary of the Bashkirian in the Donets Basin is drawn at the base of limestone K3 of the C25(K) Suite. This suite (formation) contains the same conodont association as the Vereisky Horizon of the Moscow Syneclise and the Asatausky and Vereisky horizons of the Bashkirian stratotype, South Urals. It might probably be correlated with the Aegiranum Marine Band (basal Bolsovian or basal Westphalian C) of Western Europe. The uppermost Bashkirian/Lower Moscovian deposits of the Donets Basin seem to correspond to the Atokan of North America.",
    openalex = "W2151657247",
    references = "doi105962p310413, openalexw2598746693, openalexw2601695287, openalexw2753772898"
}

Current information on the conodonts Clydagnathus windsorensis (Globensky) and Promissum pulchrum Kovács-Endrödy, together with the latest interpretations of conodont hard tissues, are reviewed and it is concluded that sufficient evidence exists to justify interpretation of the conodonts on a chordate model. A new phylogenetic analysis is undertaken, consisting of 17 chordate taxa and 103 morphological, physiological and biochemical characters; conodonts are included as a primary taxon. Various experiments with character coding, taxon deletion and the use of constraint trees are carried out. We conclude that conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata. We discuss the evolution of the nervous and sensory systems and the skeleton in the context of our optimal phylogenetic tree. There appears to be no simple evolution of free to canal-enclosed neuromasts; organised neuromasts within canals appear to have arisen at least three times from free neuromasts or neuromasts arranged within grooves. The mineralised vertebrate skeleton first appeared as odontodes of dentine or dentine plus enamel in the paraconodont/euconodont feeding apparatus. Bone appeared later, co-ordinate with the development of a dermal skeleton, and it appears to have been primitively acellular. Atubular dentine is more primitive than tubular dentine. However, the subsequent distribution of the different types of dentine (e.g. mesodentine, orthodentine), suggests that these tissue types are homoplastic. The topology of relationships and known stratigraphic ranges of taxa in our phylogeny predict the existence of myxinoids and petromyzontids in the Cambrian.

@article{doi101017s0006323199005472,
    author = "Donoghue, Philip C. J. and Forey, Peter L. and Aldridge, Richard J.",
    title = "Conodont affinity and chordate phylogeny",
    year = "2000",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "Current information on the conodonts Clydagnathus windsorensis (Globensky) and Promissum pulchrum Kovács-Endrödy, together with the latest interpretations of conodont hard tissues, are reviewed and it is concluded that sufficient evidence exists to justify interpretation of the conodonts on a chordate model. A new phylogenetic analysis is undertaken, consisting of 17 chordate taxa and 103 morphological, physiological and biochemical characters; conodonts are included as a primary taxon. Various experiments with character coding, taxon deletion and the use of constraint trees are carried out. We conclude that conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata. We discuss the evolution of the nervous and sensory systems and the skeleton in the context of our optimal phylogenetic tree. There appears to be no simple evolution of free to canal-enclosed neuromasts; organised neuromasts within canals appear to have arisen at least three times from free neuromasts or neuromasts arranged within grooves. The mineralised vertebrate skeleton first appeared as odontodes of dentine or dentine plus enamel in the paraconodont/euconodont feeding apparatus. Bone appeared later, co-ordinate with the development of a dermal skeleton, and it appears to have been primitively acellular. Atubular dentine is more primitive than tubular dentine. However, the subsequent distribution of the different types of dentine (e.g. mesodentine, orthodentine), suggests that these tissue types are homoplastic. The topology of relationships and known stratigraphic ranges of taxa in our phylogeny predict the existence of myxinoids and petromyzontids in the Cambrian.",
    url = "https://doi.org/10.1017/s0006323199005472",
    doi = "10.1017/s0006323199005472",
    openalex = "W2162521529",
    references = "bengtson1976the, doi101006dbio19941210, doi10100797814612356063, doi10100797814615696887, doi10100797894011583432, doi101007bf03044446, doi1010160028393264900107, doi1010160169534796100483, doi101016s0070215321x00026, doi101017s0006323198005167, doi101017s0022336000024963, doi101038370563a0, doi101038374798a0, doi10108002724634198110011886, doi101086413055, doi101093oxfordjournalsmolbeva025897, doi101098rstb19930082, doi101098rstb19950098, doi101111j146979981973tb04654x, doi101111j150239311983tb01993x, doi101111j150239311986tb00741x, doi101111j150239311998tb00509x, doi101111j160007221998tb02212x, doi101126science16238591265, doi101126science7008198, doi101130spe196p43, doi1016660022336020000740113oaanic20co2, doi1023071437499, doi1023071539358, doi1023072413058, doi105860choice266278, doi105860choice341536, doi105860choice501469, openalexw2207565996, openalexw2598873191, peterson1994the"
}

ABSTRACT Current information on the conodonts Clydagnathus windsorensis (Globensky) and Promissum pulchrum Kovács‐ Endrödy, together with the latest interpretations of conodont hard tissues, are reviewed and it is concluded that sufficient evidence exists to justify interpretation of the conodonts on a chordate model. A new phylogenetic analysis is undertaken, consisting of 17 chordate taxa and 103 morphological, physiological and biochemical characters; conodonts are included as a primary taxon. Various experiments with character coding, taxon deletion and the use of constraint trees are carried out. We conclude that conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata. We discuss the evolution of the nervous and sensory systems and the skeleton in the context of our optimal phylogenetic tree. There appears to be no simple evolution of free to canal‐enclosed neuromasts; organised neuromasts within canals appear to have arisen at least three times from free neuromasts or neuromasts arranged within grooves. The mineralised vertebrate skeleton first appeared as odontodes of dentine or dentine plus enamel in the paraconodont/euconodont feeding apparatus. Bone appeared later, co‐ordinate with the development of a dermal skeleton, and it appears to have been primitively acellular. Atubular dentine is more primitive than tubular dentine. However, the subsequent distribution of the different types of dentine (e.g. mesodentine, orthodentine), suggests that these tissue types are homoplastic. The topology of relationships and known stratigraphic ranges of taxa in our phylogeny predict the existence of myxinoids and petromyzontids in the Cambrian.

@article{doi101111j1469185x1999tb00045x,
    author = "Donoghue, Philip C. J. and Forey, Peter L. and Aldridge, Richard J.",
    title = "Conodont affinity and chordate phylogeny",
    year = "2000",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "ABSTRACT Current information on the conodonts Clydagnathus windsorensis (Globensky) and Promissum pulchrum Kovács‐ Endrödy, together with the latest interpretations of conodont hard tissues, are reviewed and it is concluded that sufficient evidence exists to justify interpretation of the conodonts on a chordate model. A new phylogenetic analysis is undertaken, consisting of 17 chordate taxa and 103 morphological, physiological and biochemical characters; conodonts are included as a primary taxon. Various experiments with character coding, taxon deletion and the use of constraint trees are carried out. We conclude that conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata. We discuss the evolution of the nervous and sensory systems and the skeleton in the context of our optimal phylogenetic tree. There appears to be no simple evolution of free to canal‐enclosed neuromasts; organised neuromasts within canals appear to have arisen at least three times from free neuromasts or neuromasts arranged within grooves. The mineralised vertebrate skeleton first appeared as odontodes of dentine or dentine plus enamel in the paraconodont/euconodont feeding apparatus. Bone appeared later, co‐ordinate with the development of a dermal skeleton, and it appears to have been primitively acellular. Atubular dentine is more primitive than tubular dentine. However, the subsequent distribution of the different types of dentine (e.g. mesodentine, orthodentine), suggests that these tissue types are homoplastic. The topology of relationships and known stratigraphic ranges of taxa in our phylogeny predict the existence of myxinoids and petromyzontids in the Cambrian.",
    url = "https://doi.org/10.1111/j.1469-185x.1999.tb00045.x",
    doi = "10.1111/j.1469-185x.1999.tb00045.x",
    openalex = "W4211190435",
    references = "doi101006dbio19941210, doi10100797814612356063, doi1010079789401139618, doi10100797894011583432, doi101007bf00310303, doi101007bf03044446, doi1010160169534796100483, doi101017s0022336000024963, doi101017s0080456800035237, doi101038370563a0, doi101038374798a0, doi10108002724634199710010948, doi101086413055, doi101093oso97801985404720010001, doi101098rstb19930082, doi101098rstb19950098, doi101111j146364091979tb00640x, doi101111j146979981973tb04654x, doi101111j146979981978tb03931x, doi101111j150239311986tb00741x, doi101111j150239311990tb01369x, doi101111j150239311998tb00509x, doi101126science16238591265, doi101126science7008198, doi101130spe196p43, doi101146annurevne04030181001505, doi10182618200067378198301, doi1023071437499, doi1023072412685, doi1023072413058, doi107208chicago97802262565730010001, openalexw2207565996"
}

All aspects of conodont paleontology rely on the identification and description of homologous anatomical units or elements. But the current schemes of anatomical notation and terms for orientation were formulated at a time when little was known of conodont anatomy or skeletal architecture, resulting in some confusion and difficulties in their application. With improving knowledge of conodonts, these problems are becoming increasingly acute.In an attempt to address current problems, we introduce new terms for orientation in conodonts and their elements, and a modified scheme of anatomical notation. The principal axes of the conodont body are identified as rostrocaudal, dorsoventral, and mediolateral, with opposite lateral sides designated dextral and sinistral. Anatomical notation is defined according to topological relationships between elements with reference to the principal axes of the body and takes the form of letters with numeric subscripts (e.g., P1, P2, S0-S4). The ozarkodinid apparatus serves as a standard, but the Pn-Sn scheme can be applied rigorously to all taxa that are known from natural assemblages or where an hypothesis of topological homology can be inferred from secondary morphological criteria.

@article{doi1016660022336020000740113oaanic20co2,
    author = "Purnell, Mark A. and Donoghue, Philip C. J. and Aldridge, Richard J.",
    title = "ORIENTATION AND ANATOMICAL NOTATION IN CONODONTS",
    year = "2000",
    journal = "Journal of Paleontology",
    abstract = "All aspects of conodont paleontology rely on the identification and description of homologous anatomical units or elements. But the current schemes of anatomical notation and terms for orientation were formulated at a time when little was known of conodont anatomy or skeletal architecture, resulting in some confusion and difficulties in their application. With improving knowledge of conodonts, these problems are becoming increasingly acute.In an attempt to address current problems, we introduce new terms for orientation in conodonts and their elements, and a modified scheme of anatomical notation. The principal axes of the conodont body are identified as rostrocaudal, dorsoventral, and mediolateral, with opposite lateral sides designated dextral and sinistral. Anatomical notation is defined according to topological relationships between elements with reference to the principal axes of the body and takes the form of letters with numeric subscripts (e.g., P1, P2, S0-S4). The ozarkodinid apparatus serves as a standard, but the Pn-Sn scheme can be applied rigorously to all taxa that are known from natural assemblages or where an hypothesis of topological homology can be inferred from secondary morphological criteria.",
    url = "https://doi.org/10.1666/0022-3360(2000)074<0113:oaanic>2.0.co;2",
    doi = "10.1666/0022-3360(2000)074<0113:oaanic>2.0.co;2",
    openalex = "W2205590374",
    references = "doi101017s0263593300006854, doi101038374800a0, doi101046j1420910119914020167x, doi10108011035898809452656, doi101098rstb19930082, doi101111j150239311983tb01993x, doi101111j150239311986tb00741x, doi1023071483846, doi105860choice266278, doi105860choice321516"
}

Conodonts were mostly small, elongate, eel-shaped marine animals that inhabited a variety of environments in Paleozoic and Triassic seas. Although long enigmatic, conodonts are now regarded as vertebrates and their closely controlled fossil record is not only the most extensive of all vertebrates, but it also makes conodonts the fossils of choice in upper Cambrian through Triassic biostratigraphy. Conodonts were soft-bodied except for a variety of phosphatic elements that formed a distinctive feeding apparatus. Post-mortal dissociation of the apparatus and subsequent jumbling of its elements on the sea floor led, from 1856 to about 1966, to development of an artificial, form-based taxonomy that was utilitarian, but clearly unsatisfactory as a vehicle for understanding the group in biologic terms. Natural assemblages of elements, discovered between 1879 and 1952, have been interpreted as undisturbed skeletal apparatuses, and in the mid-1960s it was determined that original composition of the apparatuses of many species could be reconstructed and statistically evaluated from collections of disjunct elements by various grouping procedures. These determinations led to an emphasis on multielement taxonomy by most (but not all) students of conodonts. Even so, only about a third of the approximately 550 valid conodont genera, have been established (or re-interpreted) in multielement terms and this makes any of the several extant schemes of suprageneric classification phylogenetically suspect. We comment on a recent scheme that recognizes 41 families assigned to some 7 orders, and suggest how it might be modified so as to square with principles of phylogenetic systematics.

@article{doi1016660022336020010751174cppf20co2,
    author = "Sweet, Walter C. and Donoghue, Philip C. J.",
    title = "CONODONTS: PAST, PRESENT, FUTURE",
    year = "2001",
    journal = "Journal of Paleontology",
    abstract = "Conodonts were mostly small, elongate, eel-shaped marine animals that inhabited a variety of environments in Paleozoic and Triassic seas. Although long enigmatic, conodonts are now regarded as vertebrates and their closely controlled fossil record is not only the most extensive of all vertebrates, but it also makes conodonts the fossils of choice in upper Cambrian through Triassic biostratigraphy. Conodonts were soft-bodied except for a variety of phosphatic elements that formed a distinctive feeding apparatus. Post-mortal dissociation of the apparatus and subsequent jumbling of its elements on the sea floor led, from 1856 to about 1966, to development of an artificial, form-based taxonomy that was utilitarian, but clearly unsatisfactory as a vehicle for understanding the group in biologic terms. Natural assemblages of elements, discovered between 1879 and 1952, have been interpreted as undisturbed skeletal apparatuses, and in the mid-1960s it was determined that original composition of the apparatuses of many species could be reconstructed and statistically evaluated from collections of disjunct elements by various grouping procedures. These determinations led to an emphasis on multielement taxonomy by most (but not all) students of conodonts. Even so, only about a third of the approximately 550 valid conodont genera, have been established (or re-interpreted) in multielement terms and this makes any of the several extant schemes of suprageneric classification phylogenetically suspect. We comment on a recent scheme that recognizes 41 families assigned to some 7 orders, and suggest how it might be modified so as to square with principles of phylogenetic systematics.",
    url = "https://doi.org/10.1666/0022-3360(2001)075<1174:cppf>2.0.co;2",
    doi = "10.1666/0022-3360(2001)075<1174:cppf>2.0.co;2",
    openalex = "W2179239323",
    references = "doi1016660022336020000740113oaanic20co2"
}

@article{doi101016s0031018201004230,
    author = "Shilong, Mei and Henderson, Charles M. and Wardlaw, Bruce R.",
    title = "Evolution and distribution of the conodonts Sweetognathus and Iranognathus and related genera during the Permian, and their implications for climate change",
    year = "2002",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/s0031-0182(01)00423-0",
    doi = "10.1016/s0031-0182(01)00423-0",
    openalex = "W2059597394",
    references = "openalexw2753772898"
}

The upper part of cores of the Onakawana B Drillhole in the Moose River Basin in northern Ontario includes the upper part of the upper member of the Williams Island Formation (22.5 m, 16 samples), and the entire overlying Long Rapids Formation (75.1 m, 49 samples). The sequence of conodonts from the drillhole was analyzed by graphic correlation as well as conventional zonation.The upper carbonate member of the Williams Island Formation correlates with lower Frasnian zones 2 to 5. Below this, mixed Frasnian and Famennian conodont faunas occur partly in a brecciated interval within the member and represent stratigraphic leak below the Frasnian. The lower member of the Long Rapids Formation correlates in its lowest part with Zone 5, followed by a hiatus of zones 6 to 8. This is succeeded by zones 9 and 10. Zone 11 is missing, followed by an interval that correlates with upper Frasnian zones 12 and 13 to within the lower Famennian Middle triangularis Zone. The Frasnian-Famennian boundary occurs within a narrow interval in the lower member. The Upper triangularis Zone and perhaps part of the Middle triangularis Zone are missing.The middle member of the Long Rapids Formation correlates with the Lower to Uppermost crepida zones. A sequence from high in the rhomboidea Zone to within the Lower marginifera to perhaps slightly into the Upper marginifera Zone occurs in the upper member of the formation.Sixteen species are described, of which seven are new: Palmatolepis angularis, P. angusta, P. mystica, P. nodosa, P. parva, Palmatolepis n. sp. A, and Mehlina? unica. Two species that affect definition and identification of the Frasnian-Famennian boundary, P. triangularis and P. ultima (=P. praetriangularis), are revised.

@article{doi1016660022336020040780371cotwia20co2,
    author = "Klapper, Gilbert and Uyeno, T. T. and Armstrong, Derek and Telford, P. G.",
    title = "CONODONTS OF THE WILLIAMS ISLAND AND LONG RAPIDS FORMATIONS (UPPER DEVONIAN, FRASNIAN-FAMENNIAN) OF THE ONAKAWANA B DRILLHOLE, MOOSE RIVER BASIN, NORTHERN ONTARIO, WITH A REVISION OF LOWER FAMENNIAN SPECIES",
    year = "2004",
    journal = "Journal of Paleontology",
    abstract = "The upper part of cores of the Onakawana B Drillhole in the Moose River Basin in northern Ontario includes the upper part of the upper member of the Williams Island Formation (22.5 m, 16 samples), and the entire overlying Long Rapids Formation (75.1 m, 49 samples). The sequence of conodonts from the drillhole was analyzed by graphic correlation as well as conventional zonation.The upper carbonate member of the Williams Island Formation correlates with lower Frasnian zones 2 to 5. Below this, mixed Frasnian and Famennian conodont faunas occur partly in a brecciated interval within the member and represent stratigraphic leak below the Frasnian. The lower member of the Long Rapids Formation correlates in its lowest part with Zone 5, followed by a hiatus of zones 6 to 8. This is succeeded by zones 9 and 10. Zone 11 is missing, followed by an interval that correlates with upper Frasnian zones 12 and 13 to within the lower Famennian Middle triangularis Zone. The Frasnian-Famennian boundary occurs within a narrow interval in the lower member. The Upper triangularis Zone and perhaps part of the Middle triangularis Zone are missing.The middle member of the Long Rapids Formation correlates with the Lower to Uppermost crepida zones. A sequence from high in the rhomboidea Zone to within the Lower marginifera to perhaps slightly into the Upper marginifera Zone occurs in the upper member of the formation.Sixteen species are described, of which seven are new: Palmatolepis angularis, P. angusta, P. mystica, P. nodosa, P. parva, Palmatolepis n. sp. A, and Mehlina? unica. Two species that affect definition and identification of the Frasnian-Famennian boundary, P. triangularis and P. ultima (=P. praetriangularis), are revised.",
    url = "https://doi.org/10.1666/0022-3360(2004)078<0371:cotwia>2.0.co;2",
    doi = "10.1666/0022-3360(2004)078<0371:cotwia>2.0.co;2",
    openalex = "W2139341130",
    references = "doi1016660022336020000740113oaanic20co2"
}

@article{doi101016jearscirev200601001,
    author = "Kaufmann, Bernd",
    title = "Calibrating the Devonian Time Scale: A synthesis of U–Pb ID–TIMS ages and conodont stratigraphy",
    year = "2006",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/j.earscirev.2006.01.001",
    doi = "10.1016/j.earscirev.2006.01.001",
    openalex = "W2164759790",
    references = "doi101016b9780444594259000202, doi101016b9780444594259000214"
}

Synopsis Little attention has been paid to the suprageneric classification for conodonts and existing schemes have been formulated without attention to homology, diagnosis and definition. We propose that cladistics providesan appropriate methodology to test existingschemes of classification and in which to explore the evolutionary relationships of conodonts. The development of a multielement taxonomy and a concept of homology based upon the position, not morphology, of elements within the apparatus provide the ideal foundation for the application of cladistics to conodonts. In an attempt to unravel the evolutionary relationships between ‘complex’ conodonts (prioniodontids and derivative lineages) we have compiled a data matrix based upon 95 characters and 61 representative taxa. The dataset was analysed using parsimony and the resulting hypotheses were assessed using a number of measures of support. These included bootstrap, Bremer Support and double‐decay; we also compared levels of homoplasy to those expected given the size of the dataset and to those expected in a random dataset. The dataset was analysed in three hierarchical tranches, representing three levels of certainty concerning multi‐element reconstructions and positional homologies. There is much agreement between the results derived from the three partitions, but some inconsistency, particularly in the precise composition of the three main evolutionary grades traditionally recognised (Prioniodontida, Prioniodinina, Ozarkodinina). This is considered to result from (a) the progressive inclusion of data that is increasingly uncertain and (b) the inclusion of increasingly distantly related taxa, introducing spurious hypotheses of homology. We tested for these by partitioning the dataset into the three main evolutionary grades and in each instance resolution was seen to increase substantially, especially among prioniodinins. Our concluding scheme of relationships is a tree derived from a compilation of the three component subtrees, which is directly compatible with the most‐parsimonious trees derived from the initial second tranche analysis with the exception of the position of Hibbardella. This is compared in detail to the main extant schemes of suprageneric classification. A formal scheme of suprageneric classification is presented and the distribution of characters with respect to component clades is considered as a basis for identifying diagnostic characters.

@article{doi101017s1477201907002234,
    author = "Donoghue, Philip C. J. and Purnell, Mark A. and Aldridge, Richard J. and Zhang, Shunxin",
    title = "The interrelationships of ‘complex’ conodonts (Vertebrata)",
    year = "2007",
    journal = "Journal of Systematic Palaeontology",
    abstract = "Synopsis Little attention has been paid to the suprageneric classification for conodonts and existing schemes have been formulated without attention to homology, diagnosis and definition. We propose that cladistics providesan appropriate methodology to test existingschemes of classification and in which to explore the evolutionary relationships of conodonts. The development of a multielement taxonomy and a concept of homology based upon the position, not morphology, of elements within the apparatus provide the ideal foundation for the application of cladistics to conodonts. In an attempt to unravel the evolutionary relationships between ‘complex’ conodonts (prioniodontids and derivative lineages) we have compiled a data matrix based upon 95 characters and 61 representative taxa. The dataset was analysed using parsimony and the resulting hypotheses were assessed using a number of measures of support. These included bootstrap, Bremer Support and double‐decay; we also compared levels of homoplasy to those expected given the size of the dataset and to those expected in a random dataset. The dataset was analysed in three hierarchical tranches, representing three levels of certainty concerning multi‐element reconstructions and positional homologies. There is much agreement between the results derived from the three partitions, but some inconsistency, particularly in the precise composition of the three main evolutionary grades traditionally recognised (Prioniodontida, Prioniodinina, Ozarkodinina). This is considered to result from (a) the progressive inclusion of data that is increasingly uncertain and (b) the inclusion of increasingly distantly related taxa, introducing spurious hypotheses of homology. We tested for these by partitioning the dataset into the three main evolutionary grades and in each instance resolution was seen to increase substantially, especially among prioniodinins. Our concluding scheme of relationships is a tree derived from a compilation of the three component subtrees, which is directly compatible with the most‐parsimonious trees derived from the initial second tranche analysis with the exception of the position of Hibbardella. This is compared in detail to the main extant schemes of suprageneric classification. A formal scheme of suprageneric classification is presented and the distribution of characters with respect to component clades is considered as a basis for identifying diagnostic characters.",
    url = "https://doi.org/10.1017/s1477201907002234",
    doi = "10.1017/s1477201907002234",
    openalex = "W2144308467",
    references = "doi101007bf03044446, doi1016660022336020000740113oaanic20co2, openalexw2732375649"
}

The Ordovician Period, long considered a supergreenhouse state, saw one of the greatest radiations of life in Earth's history. Previous temperature estimates of up to approximately 70 degrees C have spawned controversial speculation that the oxygen isotopic composition of seawater must have evolved over geological time. We present a very different global climate record determined by ion microprobe oxygen isotope analyses of Early Ordovician-Silurian conodonts. This record shows a steady cooling trend through the Early Ordovician reaching modern equatorial temperatures that were sustained throughout the Middle and Late Ordovician. This favorable climate regime implies not only that the oxygen isotopic composition of Ordovician seawater was similar to that of today, but also that climate played an overarching role in promoting the unprecedented increases in biodiversity that characterized this period.

@article{doi101126science1155814,
    author = "Trotter, Julie and Williams, Ian S. and Barnes, Christopher R. and Lécuyer, Christophe and Nicoll, Robert S.",
    title = "Did Cooling Oceans Trigger Ordovician Biodiversification? Evidence from Conodont Thermometry",
    year = "2008",
    journal = "Science",
    abstract = "The Ordovician Period, long considered a supergreenhouse state, saw one of the greatest radiations of life in Earth's history. Previous temperature estimates of up to approximately 70 degrees C have spawned controversial speculation that the oxygen isotopic composition of seawater must have evolved over geological time. We present a very different global climate record determined by ion microprobe oxygen isotope analyses of Early Ordovician-Silurian conodonts. This record shows a steady cooling trend through the Early Ordovician reaching modern equatorial temperatures that were sustained throughout the Middle and Late Ordovician. This favorable climate regime implies not only that the oxygen isotopic composition of Ordovician seawater was similar to that of today, but also that climate played an overarching role in promoting the unprecedented increases in biodiversity that characterized this period.",
    url = "https://doi.org/10.1126/science.1155814",
    doi = "10.1126/science.1155814",
    openalex = "W2028823240",
    references = "doi10100797894017960024, doi101016001670379290334f, doi101016jgca200511032, doi101016s0009254199000819, doi10102993pa03266, doi101029jb086ib04p02737, doi1011300091761319940220295baiefa23co2, doi107312webb12678, openalexw2273605253, openalexw584691296"
}

Serratognathus diversus An, Cornuodus longibasis (Lindström), Drepanodus arcuatus Pander, and eleven other less common conodonts, including Cornuodus? sp., Oistodus lanceolatus, Protopanderodus gradatus, Protoprioniodus simplicissimus, Juanognathus variabilis, Nasusgnathus dolonus, Paltodus? sp., Scolopodus houlianzhaiensis, Semiacontiodus apterus, Semiacontiodus sp. cf. S. cornuformis and Serratognathoides? sp., are described and illustrated from the Honghuayuan Formation in Guizhou, South China, concluding revision of the conodont fauna from this unit, which comprises 24 species in total. The most distinctive species in the fauna, S. diversus, consists of a trimembrate apparatus, including symmetrical Sa, asymmetrical Sb and strongly asymmetrical Sc elements. This species concept is supported by the absence of any other element types in a large collection represented by nearly 500 specimens of this species. The fauna indicates a late Tremadocian to mid-Floian age (Early Ordovician) for the Honghuayuan Formation, which was widely distributed on the Yangtze Platform in shallow water environments. Previously published biostratigraphic zonations for the Honghuayuan Formation are reviewed, and revised on the basis of our knowledge of the entire conodont fauna, supporting the establishment of three biozones, Triangulodus bifidus, Serratognathus diversus, and Prioniodus honghuayanensis biozones in ascending order. Species of Serratognathus enable correlation between Ordovician successions of South China, North China (North China Platform and Ordos Basin), Tarim Basin, and further afield into Malaysia and northwestern Australia.

@article{doi10108003115510903043655,
    author = "Zhen, Yong Yi and Percival, Ian G. and Liu, Jianbo and Zhang, Yuandong",
    title = "Conodont fauna and biostratigraphy of the Honghuayuan Formation (Early Ordovician) of Guizhou, South China",
    year = "2009",
    journal = "Alcheringa An Australasian Journal of Palaeontology",
    abstract = "Serratognathus diversus An, Cornuodus longibasis (Lindström), Drepanodus arcuatus Pander, and eleven other less common conodonts, including Cornuodus? sp., Oistodus lanceolatus, Protopanderodus gradatus, Protoprioniodus simplicissimus, Juanognathus variabilis, Nasusgnathus dolonus, Paltodus? sp., Scolopodus houlianzhaiensis, Semiacontiodus apterus, Semiacontiodus sp. cf. S. cornuformis and Serratognathoides? sp., are described and illustrated from the Honghuayuan Formation in Guizhou, South China, concluding revision of the conodont fauna from this unit, which comprises 24 species in total. The most distinctive species in the fauna, S. diversus, consists of a trimembrate apparatus, including symmetrical Sa, asymmetrical Sb and strongly asymmetrical Sc elements. This species concept is supported by the absence of any other element types in a large collection represented by nearly 500 specimens of this species. The fauna indicates a late Tremadocian to mid-Floian age (Early Ordovician) for the Honghuayuan Formation, which was widely distributed on the Yangtze Platform in shallow water environments. Previously published biostratigraphic zonations for the Honghuayuan Formation are reviewed, and revised on the basis of our knowledge of the entire conodont fauna, supporting the establishment of three biozones, Triangulodus bifidus, Serratognathus diversus, and Prioniodus honghuayanensis biozones in ascending order. Species of Serratognathus enable correlation between Ordovician successions of South China, North China (North China Platform and Ordos Basin), Tarim Basin, and further afield into Malaysia and northwestern Australia.",
    url = "https://doi.org/10.1080/03115510903043655",
    doi = "10.1080/03115510903043655",
    openalex = "W1983016387",
    references = "doi101130mem127p21, doi101826197814051698822001, openalexw2207565996"
}

The origin of jaws remains largely an enigma that is best addressed by studying fossil and living jawless vertebrates. Conodonts were eel-shaped jawless animals, whose vertebrate affinity is still disputed. The geometrical analysis of exceptional three-dimensionally preserved clusters of oro-pharyngeal elements of the Early Triassic Novispathodus, imaged using propagation phase-contrast X-ray synchrotron microtomography, suggests the presence of a pulley-shaped lingual cartilage similar to that of extant cyclostomes within the feeding apparatus of euconodonts ("true" conodonts). This would lend strong support to their interpretation as vertebrates and demonstrates that the presence of such cartilage is a plesiomorphic condition of crown vertebrates.

@article{doi101073pnas1101754108,
    author = "Goudemand, Nicolas and Orchard, Michael J. and Urdy, Séverine and Bucher, Hugo and Tafforeau, Paul",
    title = "Synchrotron-aided reconstruction of the conodont feeding apparatus and implications for the mouth of the first vertebrates",
    year = "2011",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {The origin of jaws remains largely an enigma that is best addressed by studying fossil and living jawless vertebrates. Conodonts were eel-shaped jawless animals, whose vertebrate affinity is still disputed. The geometrical analysis of exceptional three-dimensionally preserved clusters of oro-pharyngeal elements of the Early Triassic Novispathodus, imaged using propagation phase-contrast X-ray synchrotron microtomography, suggests the presence of a pulley-shaped lingual cartilage similar to that of extant cyclostomes within the feeding apparatus of euconodonts ("true" conodonts). This would lend strong support to their interpretation as vertebrates and demonstrates that the presence of such cartilage is a plesiomorphic condition of crown vertebrates.},
    url = "https://doi.org/10.1073/pnas.1101754108",
    doi = "10.1073/pnas.1101754108",
    openalex = "W2166651471",
    references = "doi101111j150239311990tb01369x, doi1016660022336020000740113oaanic20co2, doi105252g2010n4a1"
}

Abstract: Several fused clusters of conodont elements of the genera Neospathodus and Novispathodus were recovered from limestone beds at the Dienerian–Smithian and Smithian–Spathian boundaries, respectively, from several localities in Guangxi province, South China. Conodont clusters are otherwise extremely rare in the Triassic, and these are first described for the Early Triassic. The exceptional specimens partially preserve the relative three‐dimensional position and orientation of ramiform elements and are therefore extremely important for testing hypotheses on the architecture of apparatuses. These specimens partly confirm the previous reconstruction of the Novispathodus apparatus by Orchard. Within apparatuses of members of superfamily Gondolelloidea, elements previously identified as occupying the S 1 and S 2 positions instead occupy the S 2 and S 1 positions. Similarly, within apparatuses of members of the subfamily Novispathodinae, elements previously referred to S 3 and S 4 positions are reinterpreted to have occupied S 4 and S 3 positions, respectively.

@article{doi101111j14754983201201174x,
    author = "Goudemand, Nicolas and Orchard, Michael J. and Tafforeau, Paul and Urdy, Séverine and Brühwiler, Thomas and Brayard, Arnaud and Galfetti, Thomas and Bucher, Hugo",
    title = "Early Triassic conodont clusters from South China: revision of the architecture of the 15 element apparatuses of the superfamily Gondolelloidea",
    year = "2012",
    journal = "Palaeontology",
    abstract = "Abstract: Several fused clusters of conodont elements of the genera Neospathodus and Novispathodus were recovered from limestone beds at the Dienerian–Smithian and Smithian–Spathian boundaries, respectively, from several localities in Guangxi province, South China. Conodont clusters are otherwise extremely rare in the Triassic, and these are first described for the Early Triassic. The exceptional specimens partially preserve the relative three‐dimensional position and orientation of ramiform elements and are therefore extremely important for testing hypotheses on the architecture of apparatuses. These specimens partly confirm the previous reconstruction of the Novispathodus apparatus by Orchard. Within apparatuses of members of superfamily Gondolelloidea, elements previously identified as occupying the S 1 and S 2 positions instead occupy the S 2 and S 1 positions. Similarly, within apparatuses of members of the subfamily Novispathodinae, elements previously referred to S 3 and S 4 positions are reinterpreted to have occupied S 4 and S 3 positions, respectively.",
    url = "https://doi.org/10.1111/j.1475-4983.2012.01174.x",
    doi = "10.1111/j.1475-4983.2012.01174.x",
    openalex = "W2123098427",
    references = "doi101007bf03044446, doi1016660022336020000740113oaanic20co2"
}

Drygant, Daniel, Szaniawski, Hubert (2012): Lochkovian conodonts from Podolia, Ukraine, and their stratigraphic significance. Acta Palaeontologica Polonica 57 (4): 833-861, DOI: 10.4202/app.2011.0124, URL: http://dx.doi.org/10.4202/app.2011.0124

@article{doi104202app20110124,
    author = "Drygant, Daniel and Szaniawski, Hubert",
    title = "Lochkovian conodonts from Podolia, Ukraine, and their stratigraphic significance",
    year = "2012",
    journal = "Acta Palaeontologica Polonica",
    abstract = "Drygant, Daniel, Szaniawski, Hubert (2012): Lochkovian conodonts from Podolia, Ukraine, and their stratigraphic significance. Acta Palaeontologica Polonica 57 (4): 833-861, DOI: 10.4202/app.2011.0124, URL: http://dx.doi.org/10.4202/app.2011.0124",
    url = "https://doi.org/10.4202/app.2011.0124",
    doi = "10.4202/app.2011.0124",
    openalex = "W2118445091",
    references = "openalexw2598746693"
}

Abstract A preliminary summary of the lower Visean to uppermost Moscovian (Carboniferous) conodont succession and biostratigraphy of the Dianzishang section in Zhenning, Guizhou, South China is presented. Eleven conodont zones, in ascending order, can be recognized: Gnathodus praebilineatus, Gnathodus bilineatus, Lochriea ziegleri, Declinognathodus noduliferus, Neognathodus symmetricus, ‘ Streptognathodus ’ expansus (primitive form), ‘ Streptognathodus ’ expansus, Mesogondolella donbassica – Mesogondolella clarki, Idiognathodus podolskensis, Swadelina fauna and Idiognathodus swadei zones. The first occurrences of Lochriea ziegleri at the base of the Serpukhovian Stage, Declinognathodus noduliferus noduliferus at the base of the Bashkirian Stage and ‘ Streptognathodus ’ expansus at the base of the Moscovian Stage are recognized. The definitions of these stage boundaries, as well as that of the base of the Kasimovian Stage are discussed. Correlations with the Naqing section in South China, Russian and North American sections, as well as other important sections in the world, are considered.

@article{doi101017s0016756813000344,
    author = "Qi, Yuping and Hu, Keyi and Wang, Qiulai and Lin, Wei",
    title = "Carboniferous conodont biostratigraphy of the Dianzishang section, Zhenning, Guizhou, South China",
    year = "2013",
    journal = "Geological Magazine",
    abstract = "Abstract A preliminary summary of the lower Visean to uppermost Moscovian (Carboniferous) conodont succession and biostratigraphy of the Dianzishang section in Zhenning, Guizhou, South China is presented. Eleven conodont zones, in ascending order, can be recognized: Gnathodus praebilineatus, Gnathodus bilineatus, Lochriea ziegleri, Declinognathodus noduliferus, Neognathodus symmetricus, ‘ Streptognathodus ’ expansus (primitive form), ‘ Streptognathodus ’ expansus, Mesogondolella donbassica – Mesogondolella clarki, Idiognathodus podolskensis, Swadelina fauna and Idiognathodus swadei zones. The first occurrences of Lochriea ziegleri at the base of the Serpukhovian Stage, Declinognathodus noduliferus noduliferus at the base of the Bashkirian Stage and ‘ Streptognathodus ’ expansus at the base of the Moscovian Stage are recognized. The definitions of these stage boundaries, as well as that of the base of the Kasimovian Stage are discussed. Correlations with the Naqing section in South China, Russian and North American sections, as well as other important sections in the world, are considered.",
    url = "https://doi.org/10.1017/s0016756813000344",
    doi = "10.1017/s0016756813000344",
    openalex = "W2112953699",
    references = "openalexw2753772898"
}

Abstract This study reports the conodont succession across the Visean–Serpukhovian (V/S) boundary interval at the Naqing section, South China. Continuous centimetre-scale sampling of the relatively deep-water section in recent years has provided new data for a more detailed biostratigraphy of conodonts across the Visean–Serpukhovian boundary. Three conodont zones were described in ascending order: the Gnathodus bilineatus, Lochriea nodosa and Lochriea ziegleri zones. The first appearance datum (FAD) of L. ziegleri has been moved down to 60.1 m above the base of the Naqing section. The correlation of the conodont succession across the Visean–Serpukhovian boundary in the Naqing section with other sections in Eurasia is discussed.

@article{doi101017s001675681300071x,
    author = "Qi, Yuping and Nemyrovska, Tamara I. and Wang, Xiangdong and Chen, Jitao and WANG, ZHIHAO and Lane, H. Richard and Richards, B C and Hu, Keyi and Wang, Qiulai",
    title = "Late Visean – early Serpukhovian conodont succession at the Naqing (Nashui) section in Guizhou, South China",
    year = "2013",
    journal = "Geological Magazine",
    abstract = "Abstract This study reports the conodont succession across the Visean–Serpukhovian (V/S) boundary interval at the Naqing section, South China. Continuous centimetre-scale sampling of the relatively deep-water section in recent years has provided new data for a more detailed biostratigraphy of conodonts across the Visean–Serpukhovian boundary. Three conodont zones were described in ascending order: the Gnathodus bilineatus, Lochriea nodosa and Lochriea ziegleri zones. The first appearance datum (FAD) of L. ziegleri has been moved down to 60.1 m above the base of the Naqing section. The correlation of the conodont succession across the Visean–Serpukhovian boundary in the Naqing section with other sections in Eurasia is discussed.",
    url = "https://doi.org/10.1017/s001675681300071x",
    doi = "10.1017/s001675681300071x",
    openalex = "W2333945315",
    references = "doi105962p310413"
}

@article{doi101038nature12645,
    author = "Murdock, Duncan and Dong, Xiping and Repetski, John E. and Marone, Federica and Stampanoni, Marco and Donoghue, Philip C. J.",
    title = "The origin of conodonts and of vertebrate mineralized skeletons",
    year = "2013",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature12645",
    doi = "10.1038/nature12645",
    openalex = "W2087003165",
    references = "doi101002bies200900151, doi101017s0022336000024963, doi101111j150239311998tb00509x, doi105252g2010n4a1, openalexw2732375649"
}

@article{doi101016jlithos201403026,
    author = "Yuan, Dong‐xun and Shen, Shu‐zhong and Henderson, Charles M. and Chen, Jun and Zhang, Hua and Feng, Hongzhen",
    title = "Revised conodont-based integrated high-resolution timescale for the Changhsingian Stage and end-Permian extinction interval at the Meishan sections, South China",
    year = "2014",
    journal = "Lithos",
    url = "https://doi.org/10.1016/j.lithos.2014.03.026",
    doi = "10.1016/j.lithos.2014.03.026",
    openalex = "W2032641521",
    references = "doi101007bf03044446, openalexw2732375649"
}

Conodonts of the genus Lochriea offer high-resolution biostratigraphical differentiation of the upper Mississippian (Carboniferous). In particular, L. ziegleri is regarded as the most suitable index taxon for recognition of a revised Viséan–Serpukhovian boundary and selection of a Global Stratotype Section and Point. Mixed carbonate-siliciclastic Carboniferous sections from western Ireland demonstrate that gradual morphological evolution is expressed within the Lochriea lineage, evidenced by P1-elements with progressively more complex ornament appearing in a pulsed fashion in the Late Viséan. Significant diversification of the Lochriea conodonts occurs below the currently recognized base of the Namurian (identified by ammonoids), with which the basal Serpukhovian has been correlated in the past. The First Appearance Datum (FAD) of L. ziegleri in the Lugasnaghta Section of western Ireland is apparently coincident with the FAD's of other complexly ornamented Lochriea species (e.g. L. cruciformis) and corresponds with the Irish and British P2a ammonoid biozone and the lower part of the upper Cf6δ (MFZ15) foraminiferal biozone. The FAD of L. ziegleri in Ireland is closely related to other Lochriea morphotypes with complex ornament, which are difficult to identify to species level using current species definitions. These forms, recorded from the three sections examined (St Brendan's Well, Kilnamona and Lugasnaghta), may partly be explained as abnormal growth histories, evolutionary intermediate forms, etc. In some instances, however, the apparently consistent and novel morphotypes suggest that current Lochriea taxonomy needs to be re-examined. Furthermore, given the close association of the morphologies with asymmetric complex ornament and L. ziegleri, these taxa may hold significance as biostratigraphical tools in their own right.

@article{doi101111let12096,
    author = "Barham, Milo and Murray, John and Sevastopulo, George D. and Williams, D. Michael",
    title = "Conodonts of the genus Lochriea in Ireland and the recognition of the Viséan–Serpukhovian (Carboniferous) boundary",
    year = "2014",
    journal = "Lethaia",
    abstract = "Conodonts of the genus Lochriea offer high-resolution biostratigraphical differentiation of the upper Mississippian (Carboniferous). In particular, L. ziegleri is regarded as the most suitable index taxon for recognition of a revised Viséan–Serpukhovian boundary and selection of a Global Stratotype Section and Point. Mixed carbonate-siliciclastic Carboniferous sections from western Ireland demonstrate that gradual morphological evolution is expressed within the Lochriea lineage, evidenced by P1-elements with progressively more complex ornament appearing in a pulsed fashion in the Late Viséan. Significant diversification of the Lochriea conodonts occurs below the currently recognized base of the Namurian (identified by ammonoids), with which the basal Serpukhovian has been correlated in the past. The First Appearance Datum (FAD) of L. ziegleri in the Lugasnaghta Section of western Ireland is apparently coincident with the FAD's of other complexly ornamented Lochriea species (e.g. L. cruciformis) and corresponds with the Irish and British P2a ammonoid biozone and the lower part of the upper Cf6δ (MFZ15) foraminiferal biozone. The FAD of L. ziegleri in Ireland is closely related to other Lochriea morphotypes with complex ornament, which are difficult to identify to species level using current species definitions. These forms, recorded from the three sections examined (St Brendan's Well, Kilnamona and Lugasnaghta), may partly be explained as abnormal growth histories, evolutionary intermediate forms, etc. In some instances, however, the apparently consistent and novel morphotypes suggest that current Lochriea taxonomy needs to be re-examined. Furthermore, given the close association of the morphologies with asymmetric complex ornament and L. ziegleri, these taxa may hold significance as biostratigraphical tools in their own right.",
    url = "https://doi.org/10.1111/let.12096",
    doi = "10.1111/let.12096",
    openalex = "W2124131057",
    references = "openalexw2598746693"
}

Abstract The taxonomy, diversity, evolutionary lineages, and stratigraphical distributions of M iddle and early L ate T riassic conodonts are reviewed and re‐evaluated. Twenty‐five genera are recognized in the M iddle and early L ate T riassic, including a new genus cited in open nomenclature. Of these, 24 genera are assigned to two families and seven subfamilies. The family G ondolellidae consists of the subfamilies C ornudininae, E pigondolellinae, N eogondolellinae, N ovispathodinae, P aragondolellinae and P seudofurnishiinae. The family G ladigondolellidae is monotypic, consisting of the subfamily G ladigondolellinae. The genus N eostrachanognathus is not assigned to any family or subfamily as its origin is unclear. Conodont provincialism was low in the early A nisian, but from the late A nisian faunistic differences started to increase and became stronger during the early L adinian, reaching a peak around the mid‐ L adinian. Provincialism remained strong until the earliest C arnian and changed to an all‐ T riassic low in the early T uvalian. The provincialism between N orth A merica and T ethys rebounded on the specific level during the late T uvalian. Diversities on generic and specific levels have been established, and two major conodont diversity cycles are recognized: the first ranges from the B ithynian (early A nisian) to the J ulian (late early C arnian), and the second is restricted to the T uvalian (late C arnian).

@article{doi101002spp21038,
    author = "Chen, Yanlong and Krystyn, Leopold and Orchard, Michael J. and Lai, Xulong and Richoz, Sylvain",
    title = "A review of the evolution, biostratigraphy, provincialism and diversity of M iddle and early L ate T riassic conodonts",
    year = "2015",
    journal = "Papers in Palaeontology",
    abstract = "Abstract The taxonomy, diversity, evolutionary lineages, and stratigraphical distributions of M iddle and early L ate T riassic conodonts are reviewed and re‐evaluated. Twenty‐five genera are recognized in the M iddle and early L ate T riassic, including a new genus cited in open nomenclature. Of these, 24 genera are assigned to two families and seven subfamilies. The family G ondolellidae consists of the subfamilies C ornudininae, E pigondolellinae, N eogondolellinae, N ovispathodinae, P aragondolellinae and P seudofurnishiinae. The family G ladigondolellidae is monotypic, consisting of the subfamily G ladigondolellinae. The genus N eostrachanognathus is not assigned to any family or subfamily as its origin is unclear. Conodont provincialism was low in the early A nisian, but from the late A nisian faunistic differences started to increase and became stronger during the early L adinian, reaching a peak around the mid‐ L adinian. Provincialism remained strong until the earliest C arnian and changed to an all‐ T riassic low in the early T uvalian. The provincialism between N orth A merica and T ethys rebounded on the specific level during the late T uvalian. Diversities on generic and specific levels have been established, and two major conodont diversity cycles are recognized: the first ranges from the B ithynian (early A nisian) to the J ulian (late early C arnian), and the second is restricted to the T uvalian (late C arnian).",
    url = "https://doi.org/10.1002/spp2.1038",
    doi = "10.1002/spp2.1038",
    openalex = "W2288796922",
    references = "doi1016660022336020000740113oaanic20co2"
}

@article{doi101016jjsames201511004,
    author = "Scomazzon, Ana Karina and Moutinho, Luciane Profs and Nascimento, Sara and Lemos, Valesca Brasil and Matsuda, Nilo Siguehiko",
    title = "Conodont biostratigraphy and paleoecology of the marine sequence of the Tapajós Group, Early-Middle Pennsylvanian of Amazonas Basin, Brazil",
    year = "2015",
    journal = "Journal of South American Earth Sciences",
    url = "https://doi.org/10.1016/j.jsames.2015.11.004",
    doi = "10.1016/j.jsames.2015.11.004",
    openalex = "W2210256542",
    references = "openalexw2753772898"
}

@article{doi101016jpalwor201502005,
    author = "Qi, Yuping and Lambert, Lance L. and Nemyrovska, Tamara I. and Wang, Xiang-dong and Hu, Keyi and Wang, Qiu-Lai",
    title = "Late Bashkirian and early Moscovian conodonts from the Naqing section, Luodian, Guizhou, South China",
    year = "2015",
    journal = "Palaeoworld",
    url = "https://doi.org/10.1016/j.palwor.2015.02.005",
    doi = "10.1016/j.palwor.2015.02.005",
    openalex = "W1981608746",
    references = "openalexw2598746693, openalexw2753772898"
}

@incollection{doi101016bssats201610002,
    author = "Albanesi, Guillermo L. and Ortega, G.",
    title = "Conodont and Graptolite Biostratigraphy of the Ordovician System of Argentina",
    year = "2016",
    booktitle = "Stratigraphy \& timescales",
    url = "https://doi.org/10.1016/bs.sats.2016.10.002",
    doi = "10.1016/bs.sats.2016.10.002",
    openalex = "W2553474063",
    references = "doi101130mem127p21, doi101666070461, doi1018814epiiugs2001v24i1005"
}

The revision of the Famennian part of the "Late Devonian Standard Conodont Zonation" is based on the in-equivalence between biozones and time, and the rejection of the presumed single phyletic concept on which the previous zonation was based. It is also intended to simplify the zonation, eliminating the zonal groups named after only one taxon, and biozones that are defined by a Last Appearance Datum (LAD). The proposed revision is largely based on the zonation proposed by Ziegler and Sandberg (1990) and is for the most part correlatable using the same zonal markers. Modifications have only been made when strictly necessary, as the aim of the proposal is to maintain the stability of over 50 years of studies. The 22 zones constituting the revised zonation are defined by the First Appearance Datum (FAD) of species or subspecies that have a well-established stratigraphic range and wide geographic distribution. Each zone is named after the taxon for which the FAD defines the lower boundary. For each zone an association of other species useful for its identification is listed.

@article{doi103140bullgeosci1623,
    author = "Spalletta, Claudia and Perri, Maria Cristina and Over, D. Jeffrey and Corradini, Carlo",
    title = "Famennian (Upper Devonian) conodont zonation: revised global standard",
    year = "2017",
    journal = "Bulletin of Geosciences",
    abstract = {The revision of the Famennian part of the "Late Devonian Standard Conodont Zonation" is based on the in-equivalence between biozones and time, and the rejection of the presumed single phyletic concept on which the previous zonation was based. It is also intended to simplify the zonation, eliminating the zonal groups named after only one taxon, and biozones that are defined by a Last Appearance Datum (LAD). The proposed revision is largely based on the zonation proposed by Ziegler and Sandberg (1990) and is for the most part correlatable using the same zonal markers. Modifications have only been made when strictly necessary, as the aim of the proposal is to maintain the stability of over 50 years of studies. The 22 zones constituting the revised zonation are defined by the First Appearance Datum (FAD) of species or subspecies that have a well-established stratigraphic range and wide geographic distribution. Each zone is named after the taxon for which the FAD defines the lower boundary. For each zone an association of other species useful for its identification is listed.},
    url = "https://doi.org/10.3140/bull.geosci.1623",
    doi = "10.3140/bull.geosci.1623",
    openalex = "W2607421874",
    references = "doi105962p310413"
}

@book{openalexw2593019349,
    author = "Collinson, Charles William and Scott, Alan J. and Rexroad, Carl B.",
    title = "Six Charts Showing Biostratigraphic Zones, and Correlations Based on Conodonts from the Devonian and Mississippian Rocks of the Upper Mississippi Valley",
    year = "2018",
    openalex = "W2593019349"
}

@inproceedings{andgolding2020conodonts,
    author = "Golding, Martyn",
    title = "CONODONTS FROM THE NORIAN TO HETTANGIAN OF SOUTHEAST ALASKA, AND A REVIEW OF JURASSIC CONODONT OCCURRENCES",
    year = "2020",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2020am-354808",
    doi = "10.1130/abs/2020am-354808",
    openalex = "W3096198264"
}

Abstract Carboniferous conodont biostratigraphy comprises regional zonations that reflect the palaeogeographical distribution of taxa and distinct shallow-water and deep-water conodont biofacies. Some species have a global distribution and can effect high quality correlations. These taxa are incorporated into definitions of global Carboniferous chronostratigraphic units. A standard global Carboniferous zonation has not been developed. The lowermost Mississippian is zoned by Siphonodella species, excepet in shallow-water facies, where other polygnathids are used. Gnathodus species radiated during the Tournaisian and are used to define many Mississippian zones. A late Tournaisian maximum in diversity, characterized by short-lived genera, was followed by lower diversity faunas of Gnathodus species and carminate genera through the Visean and Serpukhovian. By the late Visean and Serpukhovian, Lochriea provides better biostratigraphic resolution. Shallow-water zonations based on Cavusgnathus and Mestognathus are difficult to correlate. An extinction event near the base of the Pennsylvanian was followed by the appearance of new gnathodid genera: Rhachistognathus, Declinognathodus, Neognathodus, Idiognathoides and Idiognathodus. By the middle of the Moscovian, few genera remained: Idiognathodus, Neognathodus and Swadelina. During the middle Kasimovian and Gzhelian, only Idiognathodus and Streptognathodus species were common. Near the end of the Gzhelian, a rediversification of Streptognathodus species extended into the Cisuralian.

@article{doi101144sp512202038,
    author = "Barrick, James E. and Alekseev, А. S. and Blanco‐Ferrera, Silvia and Goreva, N. V. and Hu, Keyi and Lambert, Lance L. and Nemyrovska, Tamara I. and Qi, Yuping and Ritter, Scott M. and Sanz‐López, Javier",
    title = "Carboniferous conodont biostratigraphy",
    year = "2020",
    journal = "Geological Society London Special Publications",
    abstract = "Abstract Carboniferous conodont biostratigraphy comprises regional zonations that reflect the palaeogeographical distribution of taxa and distinct shallow-water and deep-water conodont biofacies. Some species have a global distribution and can effect high quality correlations. These taxa are incorporated into definitions of global Carboniferous chronostratigraphic units. A standard global Carboniferous zonation has not been developed. The lowermost Mississippian is zoned by Siphonodella species, excepet in shallow-water facies, where other polygnathids are used. Gnathodus species radiated during the Tournaisian and are used to define many Mississippian zones. A late Tournaisian maximum in diversity, characterized by short-lived genera, was followed by lower diversity faunas of Gnathodus species and carminate genera through the Visean and Serpukhovian. By the late Visean and Serpukhovian, Lochriea provides better biostratigraphic resolution. Shallow-water zonations based on Cavusgnathus and Mestognathus are difficult to correlate. An extinction event near the base of the Pennsylvanian was followed by the appearance of new gnathodid genera: Rhachistognathus, Declinognathodus, Neognathodus, Idiognathoides and Idiognathodus. By the middle of the Moscovian, few genera remained: Idiognathodus, Neognathodus and Swadelina. During the middle Kasimovian and Gzhelian, only Idiognathodus and Streptognathodus species were common. Near the end of the Gzhelian, a rediversification of Streptognathodus species extended into the Cisuralian.",
    url = "https://doi.org/10.1144/sp512-2020-38",
    doi = "10.1144/sp512-2020-38",
    openalex = "W3109955668",
    references = "doi101002gj2519, doi101007s1143001792537, doi101144sp3761, doi105962p310413, openalexw2753772898"
}

@article{doi101016jmarmicro2024102407,
    author = "León-Caffroni, Martín A. and Scomazzon, Ana Karina and Nemyrovska, Tamara I. and Nascimento, Sara and Mantilla, Andrés Felipe Rojas and Dias, Sanmya Karolyne Rodrigues and da Rosa, Amanda Pericolo and Viccari, Jordana M. and Souza, Paulo A. and Lemos, Valesca Brasil",
    title = "Bashkirian-Moscovian (Lower–Middle Pennsylvanian) conodonts from the Amazonas Basin, northern Brazil: Biostratigraphy, biofacies, and paleobiogeographic significance for Western Gondwana",
    year = "2024",
    journal = "Marine Micropaleontology",
    url = "https://doi.org/10.1016/j.marmicro.2024.102407",
    doi = "10.1016/j.marmicro.2024.102407",
    openalex = "W4403271203",
    references = "doi1016660022336020000740113oaanic20co2, doi101666061211, openalexw2732375649"
}

Vertebrates use the phosphate mineral apatite in their skeletons, which allowed them to develop tissues such as enamel, characterized by an outstanding combination of hardness and elasticity. It has been hypothesized that the evolution of the earliest vertebrate skeletal tissues, found in the teeth of the extinct group of conodonts, was driven by adaptation to dental function. We test this hypothesis quantitatively and demonstrate that the crystallographic order increased throughout the early evolution of conodont teeth in parallel with morphological adaptation to food processing. With the c-axes of apatite crystals oriented perpendicular to the functional feeding surfaces, the strongest resistance to uniaxial compressional stress is conferred along the long axes of denticles. Our results support increasing control over biomineralization in the first skeletonized vertebrates and allow us to test models of functional morphology and material properties across conodont dental diversity.

@article{doi101038s41467024495260,
    author = "Shirley, Bryan and Leonhard, Isabella and Murdock, Duncan J E and Repetski, John and Świś, Przemysław and Bestmann, Michel and Trimby, Pat and Ohl, Markus and Plümper, Oliver and King, Helen E and Jarochowska, Emilia",
    title = "Increasing control over biomineralization in conodont evolution.",
    year = "2024",
    journal = "Nature communications",
    abstract = "Vertebrates use the phosphate mineral apatite in their skeletons, which allowed them to develop tissues such as enamel, characterized by an outstanding combination of hardness and elasticity. It has been hypothesized that the evolution of the earliest vertebrate skeletal tissues, found in the teeth of the extinct group of conodonts, was driven by adaptation to dental function. We test this hypothesis quantitatively and demonstrate that the crystallographic order increased throughout the early evolution of conodont teeth in parallel with morphological adaptation to food processing. With the c-axes of apatite crystals oriented perpendicular to the functional feeding surfaces, the strongest resistance to uniaxial compressional stress is conferred along the long axes of denticles. Our results support increasing control over biomineralization in the first skeletonized vertebrates and allow us to test models of functional morphology and material properties across conodont dental diversity.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC11190287/",
    doi = "10.1038/s41467-024-49526-0",
    openalex = "W4399856973",
    pmcid = "PMC11190287",
    pmid = "38902270",
    references = "doi101002jemt10217, doi101016003192019390160b, doi101016jtecto200508023, doi101016s0003996900000893, doi101016s0016703799002082, doi101038s41467019121857, doi101038s41467024495260, doi10108800344885678r02, doi101111j14697580200901046x, doi101144sp4098, doi1012019781420063660"
}

@article{doi101016jpalaeo2025113524,
    author = "Conwell, Christopher and Saltzman, Matthew R. and Lindskog, Anders and Eriksson, Mats E. and Griffith, Elizabeth M. and Leslie, Stephen A. and Edwards, Cole T. and Hints, Olle and Herrmann, Achim D.",
    title = "Factors affecting 87Sr/86Sr preservation in conodont apatite: An example from the Ordovician of Baltoscandia",
    year = "2025",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2025.113524",
    doi = "10.1016/j.palaeo.2025.113524",
    openalex = "W7116976680",
    references = "doi101038s41467024495260"
}

@article{doi101016jpalaeo2026113755,
    author = "Świś, Przemysław Lech and Ferretti, Annalisa and Rigo, Manuel and Letulle, Thomas and Cipriani, Anna and Medici, Luca and Malferrari, Daniele and Lugli, Federico",
    title = "Stable strontium isotopes of Late Devonian conodonts from Kowala (Poland) reveal genus-level signatures",
    year = "2026",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2026.113755",
    doi = "10.1016/j.palaeo.2026.113755",
    openalex = "W7140181208",
    references = "doi101016jgca202505006, doi101038s41467024495260"
}

Conodont elements are components of the feeding apparatus of extinct early jawless vertebrates named conodonts. The shape of these tooth-like elements has been explored through different approaches to test whether their morphological changes through time were related to trophic ecology, environmental pressure or ontogeny. Several morphometric analyses have previously been performed on the 2D outline of P1 elements belonging to the conodont genus Palmatolepis from the Upper Devonian (381–360 Ma) of the Montagne Noire (France). These analyses showed a general decrease in breadth of P1 elements, which was interpreted as a long-term response to a change in available food resources and/or a possible change in the trophic position of this conodont. In contrast, analyses of calcium stable isotopes ratio have shown that no changes occurred in δ44/42Ca through time, suggesting that Palmatolepis did not change its trophic position despite the mentioned change in element morphology. To further investigate changes in Palmatolepis morphology through time, 3D topographic analyses were performed on Palmatolepis P1 elements spanning the Famennian. The results of this analysis highlight the first evidence of a sharpness increase over time in this genus. This covariation between the platform reduction and the increase in blade sharpness through time suggests morphofunctional changes allowing a more efficient processing of their prey. Moreover, allometric changes in Palmatolepis gracilis, the latest representative of the Palmatolepis genus, bring new insights into the palaeoecology of this species.

@article{doi1018261let5932,
    author = "Goudemez, Cédric and Assémat, Alexandre and Thiery, Ghislain and Girard, Catherine",
    title = "3D topography as an indicator of change in food processing ability in elements of the conodont genus Palmatolepis",
    year = "2026",
    journal = "Lethaia",
    abstract = "Conodont elements are components of the feeding apparatus of extinct early jawless vertebrates named conodonts. The shape of these tooth-like elements has been explored through different approaches to test whether their morphological changes through time were related to trophic ecology, environmental pressure or ontogeny. Several morphometric analyses have previously been performed on the 2D outline of P1 elements belonging to the conodont genus Palmatolepis from the Upper Devonian (381–360 Ma) of the Montagne Noire (France). These analyses showed a general decrease in breadth of P1 elements, which was interpreted as a long-term response to a change in available food resources and/or a possible change in the trophic position of this conodont. In contrast, analyses of calcium stable isotopes ratio have shown that no changes occurred in δ44/42Ca through time, suggesting that Palmatolepis did not change its trophic position despite the mentioned change in element morphology. To further investigate changes in Palmatolepis morphology through time, 3D topographic analyses were performed on Palmatolepis P1 elements spanning the Famennian. The results of this analysis highlight the first evidence of a sharpness increase over time in this genus. This covariation between the platform reduction and the increase in blade sharpness through time suggests morphofunctional changes allowing a more efficient processing of their prey. Moreover, allometric changes in Palmatolepis gracilis, the latest representative of the Palmatolepis genus, bring new insights into the palaeoecology of this species.",
    url = "https://doi.org/10.18261/let.59.3.2",
    doi = "10.18261/let.59.3.2",
    openalex = "W7124455726",
    references = "doi101038s41467024495260"
}