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Chondrenchelys problematica (Traquair, 1888) redescribed: a Lower Carboniferous, eel-like holocephalan from Scotland

Published online by Cambridge University Press:  04 July 2014

John A. Finarelli  and
Michael I. Coates
John A. Finarelli
Affiliation:
School of Biology and Environmental Science, Science Centre West and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland. Email: [email protected]
Michael I. Coates
Affiliation:
Department of Organismal Biology and Anatomy, University of Chicago, 1027 E 57th St, Chicago, IL 60637, USA. Email: [email protected]
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Abstract

Chondrenchelys problematica, from the Viséan (Holkerian) of Scotland, is the earliest holocephalan known from extensive cranial and postcranial material. Here, we provide a comprehensive new description of this taxon using three new specimens, in which we observe many morphological features for the first time. Much of the cranial morphology is closer to that of living chimaeroid holocephalans than was previously appreciated. For this reason, we provide original figures illustrating the chondrocranium of a hatchling Callorhinchus milii demonstrating these similarities. In Chondrenchelys, although the jaw articulation is positioned at the posterior margin of the orbit, the high-walled lamina orbitonasalis and densely-mineralised antorbital crest provide evidence for forward rotation of the jaw adductor musculature. Preserved foramina for the efferent superficial ophthalmic nerves show that the sensory organs on the rostrum were enervated in a manner similar to modern sharks, with the ophthalmic nerves not enclosed in an ethmoid canal, as in modern holocephalans. The conjunction of numerous distinctly holocephalan features with those that are otherwise general to Chondrichthyes demonstrates a decoupling of several of the structural conditions that characterise the distinctive morphological complex of the extant holocephalan skull. The anguiliform postcranium is more elongate than previously reconstructed, and it is now clear that the axial skeleton extended beyond the posterior extremity of the elongate dorsal fin. Morphological characters are reviewed with a view to further phylogenetic analyses. We recommend using the appearance of Chondrenchelys at 336.5 Ma as a hard minimum age for the last common ancestor of elasmobranchs and chimaeroids, because of its secure association with other holocephalans, and current uncertainties concerning elasmobranch stem lineage membership.

Keywords

ChondrichthyesHolocephalinode calibrationPalaeozoic
Type
Articles
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 105 , Issue 1 , March 2014 , pp. 35 - 59
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Copyright © The Royal Society of Edinburgh 2014 

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References

6. References

Agassiz, L. 1838. Recherche sur les Poissons Fossiles, Vol. 3, Neuchâtel, Switzerland: Petitpierre.Google Scholar
Anderson, P. S. L. 2008. Cranial muscle homology across modern gnathostomes. Biological Journal of the Linnean Society 94, 195–216.Google Scholar
Anderson, P. S. L., Friedman, M., Brazeau, M. D. & Rayfield, E. J. 2011. Initial radiation of jaws demonstrated stability despite faunal and environmental change. Nature 476, 206–09.CrossRefGoogle ScholarPubMed
Baker, M. E. 2010. 11 beta–Hydroxysteroid dehydrogenase-type 2 evolved from an ancestral 17 beta-Hydroxysteroid dehydrogenase-type 2. Biochemical and Biophysical Research Communications 399, 215–20.Google Scholar
Berg, L. S. 1940. Sistema ryboobraznykh i ryb, nynezhivushchik i iskopaemykh [Classification of fishes, both recent and fossil]. Trudy Zoologicheskogo Instituta Akademii Nauk SSSR [Proceedings of the Zoological Institute, USSR Academy of Sciences] 5, 1–517.Google Scholar
Bonaparte, C. 1832. Selachorum tabula analytica. Nuovi Annali della Scienza Naturali (Bologna) 1, 195–214.Google Scholar
Bradley Dyne, M. 1939. The skull of Amphicentrum granulosum . Proceedings of the Zoological Society of London 109, 195–210.Google Scholar
Brazeau, M. D. 2009. The braincase and jaws of a Devonian ‘acanthodian' and modern gnathostome origins. Nature 457, 305–08.CrossRefGoogle ScholarPubMed
Callaway, E. 2012. Evolutionary biology: the lost appetites. Nature 486, S16–S17.Google Scholar
Carroll, R. L. 1997. Patterns and Processes of Vertebrate Evolution, 448. Cambridge, UK: Cambridge University Press. 464 pp.Google Scholar
Coates, M. I. & Gess, R. W. 2007. A new reconstruction of Onchoselache traquairi, comments on early chondrichthyan pectoral girdles and hybodontiform phylogeny. Palaeontology 50, 1421–46.Google Scholar
Coates, M. I. & Sequeira, S. E. K. 1998. The braincase of a primitive shark. Transactions of the Royal Society of Edinburgh: Earth Sciences 89, 63–85.CrossRefGoogle Scholar
Coates, M. I. & Sequeira, S. E. K. 2001. A new stethacanthid chondrichthyan from the Lower Carboniferous of Bearsden, Scotland. Journal of Vertebrate Paleontology 21, 438–59.Google Scholar
Cossey, P. J., Adams, A. E., Purnell, M. A., Whitely, M. J., Whyte, M. A. & Wright, V. P. (eds) 2004. British Lower Carboniferous stratigraphy. Geological Conservation Review Series 29, 617. Peterborough: Joint Nature Conservation Committee.Google Scholar
Darras, L., Derycke, C., Blieck, A. & Vachard, D. 2008. The oldest holocephalan (Chondrichthyes) from the Middle Devonian of the Boulonnais (Pas-de-Calais, France). Comptes Rendus Palevol 7, 297–304.Google Scholar
Davies, W. L., Carvalho, L. S., Tay, B. H., Hunt, D. M., Brenner, S. & Venkatesh, B. 2009. Into the blue: Gene duplication and loss underlie color vision adaptations in a deep-sea chimaera, the elephant shark Callorhinchus milii . Genome Research 19, 415–26.CrossRefGoogle Scholar
Davis, S. P., Finarelli, J. A. & Coates, M. I. 2012. Acanthodes reveals shark-like conditions in last common ancestor of modern jawed vertebrates. Nature 486, 247–250.CrossRefGoogle Scholar
de Beer, G. R. 1937. The Development of the Vertebrate Skull. Chicago: University of Chicago Press.Google Scholar
de Beer, G. R. & Moy-Thomas, J. A. 1935. On the skull of the Holocephali. Philosophical Transactions of the Royal Society of London – B 224, 287–312.Google Scholar
Dean, B. 1906. Chimaeroid fishes and their development 32. Washington, D.C.: Carnegie Institute.Google Scholar
Dick, J. R. F. 1978. On the Carboniferous shark Tristychius arcuatus from Scotland, UK. Transactions of the Royal Society of Edinburgh 70, 63–109.CrossRefGoogle Scholar
Didier, D. 1995. Phylogenetic systematics of extant chimaeroid fishes (Holocephali, Chimaeroidei). American Museum Novitates 3119, 1–86.Google Scholar
Didier, D. A., Leclair, E. E. & Vanbuskirk, D. R. 1998. Embryonic staging and external features of development of the chimaeroid fish, Callorhinchus milli (Holocephali, Callorhinchidae). Journal of Morphology 236, 25–47.Google Scholar
Didier, D., Kemper, J. M. & McEachran, J. D. 2012. Phylogeny, Biology, and Classification of Extant Holocephalans. In Carrier, J. C., Musick, J. A. & Heithaus, M. R. (eds) Biology of Sharks and Their Relatives, 97–124. Boca Raton, FL: CRC Press.CrossRefGoogle Scholar
Dineley, D. L. & Metcalf, S. J. 1999. Fossil Fishes of Great Britain, 16. Peterborough: Joint Nature Conservation Committee.Google Scholar
Edgeworth, F. H. 1935. The cranial muscles of vertebrates, 493. Cambridge, UK: Cambridge University Press.Google Scholar
Finarelli, J. A. & Coates, M. I. 2012. First tooth-set outside the jaws in a vertebrate. Proceedings of the Royal Society of London Series B-Biological Sciences 279, 775–79.Google Scholar
Frickhinger, K. A. 1991. Fossilien Atlas: Fische. Mergus Verlag fuer Natur- und Heimtierkunde, Melle.Google Scholar
George, T. N., Johnson, G. A. L., Mitchell, M., Prentice, J. E., Ramsbottom, W. H. C., Sevastopulo, G. D. & Wilson, R. B. A. 1976. Correlation of Dinantian rocks in the British Isles. Geological Society, London, Special Report 7. 87 pp.Google Scholar
Gillis, J. A., Dahn, R. D. & Shubin, N. H. 2009. Shared developmental mechanisms pattern the vertebrate gill arch and paired fin skeletons. Proceedings of the National Academy of Sciences of the United States of America 106, 5720–24.CrossRefGoogle ScholarPubMed
Gillis, J. A., Rawlinson, K. A., Bell, J., Lyon, W. S., Baker, C. V. H. & Shubin, N. H. 2011. Holocephalan embryos provide evidence for gill arch appendage reduction and opercular evolution in cartilaginous fishes. Proceedings of the National Academy of Sciences of the United States of America 108, 1507–12.CrossRefGoogle ScholarPubMed
Gillis, J. A., Modrell, M. S. & Baker, C. V. H. 2013. Developmental evidence for serial homology of the vertebrate jaw and gill arch skeleton. Nature Communications 4, 1436.Google Scholar
Ginter, M., Hampe, O. & Duffin, C. 2010. Chondrichthyes: Paleozoic Elasmobranchii: Teeth. In Schultze, H.-P (ed.) Handbook of Paleoichthyology, 168. München: Verlag Dr. Friedrich Pfeil.Google Scholar
Ginter, M. & Sun, Y. 2007. Chondrichthyan remains from the Lower Carboniferous of Muhua, southern China. Acta Palaeontologica Polonica 52, 705–27.Google Scholar
Goodrich, E. S. 1930. Studies on the Structure and Development of Vertebrates. Chicago, IL: University of Chicago Press.CrossRefGoogle Scholar
Gradstein, F. M., Ogg, J. G., Schmitz, M. & Ogg, G. 2012. The Geologic Time Scale, 1176. Oxford, UK: Elsevier.Google Scholar
Grogan, E. D., Lund, R. & Didier, D. 1999. Description of the chimaerid jaw and its phylogenetic origins. Journal of Morphology 239, 45–59.Google Scholar
Grogan, E. D., Lund, R. & Greenfest-Allen, E. 2012. The Origin and Relationships of Early Chondrichthyans. In Carrier, J. C., Musick, J. A. & Heithaus, M. R. (eds) Biology of Sharks and Their Relatives, 3–31. Boca Raton, FL: CRC Press.Google Scholar
Hay, O. P. 1899. On some changes in the names, generic and specific, of certain fossil fishes. American Naturalist 33, 783–92.CrossRefGoogle Scholar
Heidtke, U. H. J. & Krätschmer, K. 2001. Glabachus adentatus nov. gen. et sp., ein primitiver Hai aus dem Obern Givetium (Oberes Mitteldevon) der Bergisch Gladbach-Paffrath-Mulde (Rheinisches Schiefergebirge). Mainzer Geowissenschaftliche Mitteilungen 30, 105–22.Google Scholar
Huxley, T. H. 1880. A manual of the anatomy of vertebrated animals. New York: D. Appleton.Google Scholar
Inoue, J. G., Miya, M., Lam, K., Tay, B. H., Danks, J. A., Bell, J., Walker, T. I. & Venkatesh, B. 2010. Evolutionary origin and phylogeny of the modern holocephalans (Chondrichthyes: Chimaeriformes): a mitogenomic perspective. Molecular Biology and Evolution 27, 2576–86.Google Scholar
Janvier, P. 1996. Early vertebrates. Oxford Monographs on Geology and Geophysics 33. Oxford: Clarendon Press.Google Scholar
Kakumura, K., Watanabe, S., Bell, J. D., Donald, J. A., Toop, T., Kaneko, T. & Hyodo, S. 2009. Multiple urea transporter proteins in the kidney of holocephalan elephant fish (Callorhinchus milii). Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 154, 239–47.Google Scholar
Kesteven, H. L. 1932. The anatomy of the head of Callorhynchus antarcticus . Journal of Anatomy 67, 443–74.Google Scholar
Khonsari, R., Seppala, M., Pradel, A., Dutel, H., Clement, G., Lebedev, O., Ghafoor, S., Rothova, M., Tucker, A., Maisey, J., Fan, C.-M., Kawasaki, M., Ohazama, A., Tafforeau, P., Franco, B., Helms, J., Haycraft, C., David, A., Janvier, P., Cobourne, M. & Sharpe, P. 2013. The buccohypophyseal canal is an ancestral vertebrate trait maintained by modulation in sonic hedgehog signaling. BMC Biology 11, 27.Google Scholar
Lane, J. A. & Maisey, J. G. 2009. Pectoral anatomy of Tribodus limae (Elasmobranchii: Hybodontiformes) from the Lower Cretaceous of northwestern Brazil. Journal of Vertebrate Paleontology 29, 25–38.CrossRefGoogle Scholar
Larsson, T. A., Tay, B. H., Sundstrom, G., Fredriksson, R., Brenner, S., Larhammar, D. & Venkatesh, B. 2009. Neuropeptide Y-family peptides and receptors in the elephant shark, Callorhinchus milii confirm gene duplications before the gnathostome radiation. Genomics 93, 254–60.Google Scholar
Licht, M., Schmuecker, K., Huelsken, T., Hanel, R., Bartsch, P. & Paeckert, M. 2012. Contribution to the molecular phylogenetic analysis of extant holocephalan fishes (Holocephali, Chimaeriformes). Organisms Diversity & Evolution 12, 421–32.Google Scholar
Lumsden, G. I., Tulloch, W., Howells, M. F. & Davies, A. 1967. The geology of the neighbourhood of Langholm (Sheet 11). In (eds) Memoirs of the Geological Survey of Great Britain, 255. London: HMSO.Google Scholar
Lund, R. 1982. Harpagofututor volsellorhinus new genus and species (Chondrichthyes, Chondrenchelyiformes) from the Namurian Bear Gulch Limestone, Chondrenchelys problematica Traquair (Viséan) and their sexual dimorphism. Journal of Paleontology 56, 938–58.Google Scholar
Lund, R. 1985. The morphology of Falcatus falcatus (St. John and Worthen), a Mississippian stethacanthid chondrichthyan from the Bear Gulch Limestone of Montana. Journal of Vertebrate Paleontology 5, 1–19.Google Scholar
Lund, R. 1986. On Damocles serratus nov. gen. et sp. (Elasmobranchii: Cladodontida) from the Upper Mississippian Bear Gulch Limestone of Montana. Journal of Vertebrate Paleontology 6, 12–19.Google Scholar
Lund, R. & Grogan, E. D. 2004. Two tenaculum-bearing Holocephalimorpha (Chondrichthyes) from the Bear Gulch Limestone (Chesterian, Serpukhovian) of Montana, USA. Part 1. In Arratia, G., Wilson, M. V. H. & Cloutier, R. (eds) Recent Advances in the Origin and Early Radiation of Vertebrates, München: Verlag Dr. Friedrich Pfeil.Google Scholar
Lund, R. & Zangerl, R. 1974. Squatinactus caudispinatus, a new elasmobranch from the Upper Mississippian of Montana. Annals of Carnegie Museum 45, 43–54.CrossRefGoogle Scholar
MacDonald, R. B., Debiais-Thibaud, M., Martin, K., Poitras, L., Tay, B. H., Venkatesh, B. & Ekker, M. 2010. Functional conservation of a forebrain enhancer from the elephant shark (Callorhinchus milii) in zebrafish and mice. BMC Evolutionary Biology 10, 157.Google Scholar
Maisey, J. G. 1983. Cranial anatomy of Hybodus basanus Egerton from the Lower Cretaceous of England. American Museum Novitates 2758, 1–64.Google Scholar
Maisey, J. G. 1984. Chondrichthyan phylogeny: A look at the evidence. Journal of Vertebrate Paleontology 4, 359–71.CrossRefGoogle Scholar
Maisey, J. G. 2005. Braincase of the upper Devonian shark Cladodoides wildungensis (Chondrichthyes, Elasmobranchii), with observations on the braincase in early chondrichthyans. Bulletin of the American Museum of Natural History 288, 1–103.Google Scholar
Maisey, J. G. 2007. The braincase in Paleozoic symmoriiform and cladoselachian sharks. Bulletin of the American Museum of Natural History 307, 1–122.Google Scholar
Maisey, J. G. 2012. What is an elasmobranch'? The impact of palaeontology in understanding elasmobranch phylogeny and evolution. Journal of Fish Biology 80, 918–51.Google Scholar
Maisey, J. G., Naylor, G. J. P. & Ward, D. J. 2004. Mesozoic elasmobranchs, neoselachian phylogeny and the rise of modern elasmobranch diversity. In Arratia, G. & Tintori, A. (eds) Mesozoic Fishes 3 – Systematics, Paleoenvironments and Biodiversity, 17–56. München: Verlag Dr. Friedrich Pfeil.Google Scholar
Maisey, J. G. & Lane, J. A. 2010. Labyrinth morphology and the evolution of low-frequency phonoreception in elasmobranchs. Comptes Rendus Palevol 9, 289–309.Google Scholar
Marinelli, W. & Strenger, A. 1959. Vergleichende Anatomie und Morphologie der Wirbeltiere, Vol. 3: Squalus acanthias. Vienna: Franz Deuticke.Google Scholar
McCoy, F. 1855. Description of the British Paleozoic fossils in the Geological Museum of the University of Cambridge. Cambridge, UK: Cambridge University Press.Google Scholar
Mehta, R. S., Ward, A. B., Alfaro, M. E. & Wainwright, P. C. 2010. Elongation of the body in eels. Integrative and Comparative Biology 50, 1091–105.CrossRefGoogle ScholarPubMed
Moy-Thomas, J. A. 1935. The structure and affinities of Chondrenchelys problematica, Traquair. Proceedings of the Zoological Society of London 105, 391–404.Google Scholar
Moy-Thomas, J. A. 1936. On the structure and affinities of the Carboniferous cochliodont Helodus simplex . Geological Magazine 73, 488–503.Google Scholar
Mulley, J. F., Zhong, Y. F. & Holland, P. W. H. 2009. Comparative genomics of chondrichthyan Hoxa clusters. BMC Evolutionary Biology 9, 218.Google Scholar
Nelson, G. J. 1966. Gill arches of teleostean fishes of the order Anguilliformes. Pacific Science 20, 391–408.Google Scholar
Niimura, Y. 2009. On the origin and evolution of vertebrate olfactory receptor genes: Comparative genome analysis among 23 chordate species. Genome Biology and Evolution 1, 34–44.Google Scholar
Oulion, S., Debiais-Thibaud, M., d'Aubenton-Carafa, Y., Thermes, C., Da Silva, C., Bernard-Samain, S., Gavory, F., Wincker, P., Mazan, S. & Casane, D. 2010. Evolution of Hox gene clusters in gnathostomes: insights from a survey of a shark (Scyliorhinus canicula) transcriptome. Molecular Biology and Evolution 27, 2829–38.Google Scholar
Oulion, S., Borday-Birraux, V., Debiais-Thibaud, M., Mazan, S., Laurenti, P. & Casane, D. 2011. Evolution of repeated structures along the body axis of jawed vertebrates, insights from the Scyliorhinus canicula Hox code. Evolution & Development 13, 247–59.Google Scholar
Parham, J. F., Donoghue, P. C. J., Bell, C. J., Calway, T. D., Head, J. J., Holroyd, P. A., Inoue, J. G., Irmis, R. B., Joyc, W. G., Ksepka, D. T., Patane, J. S. L., Smith, N. D., Tarver, J. E., van Tuinen, M., Yang, Z., Angielczyk, K. D., Greenwood, J. M., Hipsley, C. A., Jacobs, L., Makovicky, P. J., Mueller, J., Smith, K. T., Theodor, J. M., Warnoc, R. C. M. & Benton, M. J. 2012. Best Practices for Justifying Fossil Calibrations. Systematic Biology 61, 346–59.Google Scholar
Patterson, C. 1965. Phylogeny of the chimaeroids. Philosophical Transactions of the Royal Society of London – B 249, 101–219.Google Scholar
Patterson, C. 1992. Interpretation of the toothplates of chimaeroid fishes. Zoological journal of the Linnean Society 106, 33–61.Google Scholar
Pradel, A. 2010. Skull and brain anatomy of Late Carboniferous Sibyrhynchidae (Chondrichthyes, Iniopterygia) from Kansas and Oklahoma (USA). Geodiveritas 32, 595–661.Google Scholar
Pradel, A., Langer, M., Maisey, J. G., Geffard-Kuriyama, D., Cloetens, P., Janvier, P. & Tafforeau, P. 2009a. Skull and brain of a 300-million-year-old chimaeroid fish revealed by synchrotron holotomography. Proceedings of the National Academy of Sciences of the United States of America 106, 5224–28.CrossRefGoogle ScholarPubMed
Pradel, A., Maisey, J. G., Tafforeau, P. & Janvier, P. 2009b. An enigmatic gnathostome vertebrate skull from the Middle Devonian of Bolivia. Acta Zoologica 90, 123–33.Google Scholar
Pradel, A., Tafforeau, P. & Janvier, P. 2010. Study of the pectoral girdle and fins of the Late Carboniferous sibyrhynchid iniopterygians (Vertebrata, Chondrichthyes, Iniopterygia) from Kansas and Oklahoma (USA) by means of microtomography, with comments on iniopterygian relationships. Comptes Rendus Palevol 9, 377–87.Google Scholar
Pradel, A., Tafforeau, P., Maisey, J. G. & Janvier, P. 2011. A new Paleozoic Symmoriiformes (Chondrichthyes) from the Late Carboniferous of Kansas (USA) and cladistic analysis of early chondrichthyans. PLoS One 6(9), e24938.Google Scholar
Pradel, A., Didier, D., Casane, D., Tafforeau, P. & Maisey, J. G. 2013. Holocephalan Embryo Provides New Information on the Evolution of the Glossopharyngeal Nerve, Metotic Fissure and Parachordal Plate in Gnathostomes. PLoS One 8, e66988.Google Scholar
Pradel, A., Maisey, J. G., Tafforeau, P., Mapes, R. H. & Mallatt, J. 2014. A Palaeozoic shark with osteichthyan-like branchial arches. Nature 509, 608–11.Google Scholar
Ravi, V., Lam, K., Tay, B. H., Tay, A., Brenner, S. & Venkatesh, B. 2009. Elephant shark (Callorhinchus milii) provides insights into the evolution of Hox gene clusters in gnathostomes. Proceedings of the National Academy of Sciences – USA 106, 16327–32.Google Scholar
Ribbnik, A. J. 1971. Contributions to the functional morphology of fishes part IV: the jaw mechanism and feeding of the holocephalan, Callorhynchus capenis Dumeril. Zoologica Africana 6, 45–73.Google Scholar
Sallan, L. C. 2012. Tetrapod-like axial regionalization in an early ray-finned fish. Proceedings of the Royal Society, B Biological Sciences 279(1741), 3264–71.Google Scholar
Sallan, L. C. & Coates, M. I. 2010. End-Devonian extinction and a bottleneck in the early evolution of modern jawed vertebrates. Proceedings of the National Academy of Sciences of the United States of America 107, 10131–35.Google Scholar
Schaefer, J. T. & Summers, A. P. 2005. Batoid wing skeletal structure: Novel morphologies, mechanical implications, and phylogenetic patterns. Journal of Morphology 264, 298–313.Google Scholar
Schaeffer, B. 1981. The xenacanth shark neurocranium with comments on elasmobranch monophyly. Bulletin of the American Museum of Natural History 169, 1–66.Google Scholar
Schram, F. 1983. Lower Carboniferous biota of Glencartholm, Eskdale, Dumfriesshire. Scottish Journal of Geology 19, 1–15.Google Scholar
Smith, M. M., Smithson, T. R. & Campbell, K. S. W. 1987. The relationships of Uronemus: a Carboniferous dipnoan with highly modified tooth plates. Philosophical Transactions of the Royal Society B Biological Sciences 317, 299–327.Google Scholar
Smith, M. M. & Chang, M. M. 1990. The dentition of Diabolepis speratus Chang and Yu, with further consideration of its relationships and the primitive dipnoan dentition. Journal of Vertebrate Paleontology 10, 420–33.Google Scholar
Smithson, T. R., Wood, S. P., Marshall, J. E. A. & Clack, J. A. 2012. Earliest Carboniferous tetrapod and arthropod faunas from Scotland populate Romer's Gap. Proceedings of the National Academy of Sciences 109(12), 4532–37.Google Scholar
Stahl, B. J. 1999. Chondrichthyes III: Holocephali. In Schultze, H.-P. (ed.) Handbook of Paleoichthyology. 164 pp. München: Verlag Dr. Friedrich Pfeil.Google Scholar
Stahl, B. J. & Hansen, M. C. 2000. Dentition of Deltodus angularis (Holocephali, Cochliodontidae) inferred from associated toothplates. Copeia 4, 1090–96.Google Scholar
Stahl, B. J. & Parris, D. C. 2004. The complete dentition of Edaphodon mirificus (Chondrichthyes: Holocephali) from a single individual. Journal of Paleontology 78, 388–92.Google Scholar
Traquair, R. H. 1879. On the structure and affinities of the Platysomidae. Transactions of the Royal Society of Edinburgh 29, 343–91.Google Scholar
Traquair, R. H. 1888a. Further notes on Carboniferous Selachii. Proceedings of the Royal Physical Society of Edinburgh 9, 349–61.Google Scholar
Traquair, R. H. 1888b. Further notes on Carboniferous Selachii. Geological Magazine 5, 101–04.Google Scholar
Trinajstic, K., Long, J. A., Johanson, Z., Young, G. C. & Senden, T. 2012. New morphological information on the ptyctodontid fishes (Placodermi, Ptyctodontida) from Western Australia. Journal of Vertebrate Paleontology 32, 757–80.Google Scholar
Venkatesh, B., Lee, A. P., Ravi, V., Maurya, A. K., Lian, M. M., Swann, J. B., Ohta, Y., Flajnik, M. F., Sutoh, Y., Kasahara, M., Hoon, S., Gangu, V., Roy, S. W., Irimia, M., Korzh, V., Kondrychyn, I., Lim, Z. W., Tay, B.-H., Tohari, S., Kong, K. W., Ho, S., Lorente-Galdos, B., Quilez, J., Marques-Bonet, T., Raney, B. J., Ingham, P. W., Tay, A., Hillier, L. W., Minx, P., Boehm, T., Wilson, R. K., Brenner, S. & Warren, W. C. 2014. Elephant shark genome provides unique insights into gnathostome evolution. Nature 505, 174–79.Google Scholar
Winchell, C. J., Sullivan, J., Cameron, C. B., Swalla, B. J. & Mallatt, J. 2002. Evaluating Hypotheses of Deuterostome Phylogeny and Chordate Evolution with New LSU and SSU Ribosomal DNA Data. Molecular Biology and Evolution 19, 762–76.Google Scholar
Wood, S. P. 1982. New basal Namurian (Upper Carboniferous) fishes and crustaceans found near Glasgow. Nature 297, 574–77.Google Scholar
Zangerl, R. 1973. Iniopterygia a new order of chondrichthyan fishes from Pennsylvanian of North America. Fieldiana: Geology Memoirs 6, 1–66.Google Scholar
Zangerl, R. 1981. Chondrichthyes I: Paleozoic Elasmobranchii. In Schultze, H.-P. (ed.) Handbook of Paleoichthyology. Stuttgart: Gustav Fischer Verlag.Google Scholar
Zangerl, R. 1997. Cervifurca nasuta n. gen. et sp., an interesting member of the Iniopterygidae (Subterbranchialia, Chondrichthyes) from the Pennsylvanian of Indiana, USA. Fieldiana: Geology 35, 1–24.Google Scholar
Zhu, M., Yu, X., Ahlberg, P. E., Choo, B., Lu, J., Qiao, T., Qu, Q., Zhao, W., Jia, L., Blom, H. & Zhu, Y. a. 2013. A Silurian placoderm with osteichthyan-like marginal jaw bones. Nature 502, 188–93.CrossRefGoogle ScholarPubMed