Eugeneodontiformes

Eugeneodontiformes
Temporal range: Early Carboniferous (Serpukhovian) to Early Triassic (Olenekian)
Body fossil of Romerodus orodontus, a caseodont
Jaw cartilage and teeth of Edestus (or Edestodus) minor, an edestoid
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Holocephali
Order: †Eugeneodontiformes
Zangerl, 1981
Families

See text

Synonyms
  • Eugeneodontida

Eugeneodontiformes (also called Eugeneodontida) is an extinct and poorly known order of cartilaginous fishes. They possessed "tooth-whorls" on the symphysis of either the lower or both jaws, and pectoral fins supported by long radials. They probably lacked pelvic fins and anal fins.[1] The palatoquadrate was either fused to the skull or reduced in various members of the group. They are now determined to be within the Holocephali; their closest living relatives are chimaeras.[2] The eugeneodonts are named after paleontologist Eugene S. Richardson, Jr.[3] The group first appeared in the fossil record during the late Mississippian (Serpukhovian),[4] and the last eugeneodonts are known from the Early Triassic (Olenekian).[5]

Members of the Eugeneodontiformes are further classified into two superfamilies and either four, five or six different families. The Helicoprionidae (or Agassizodontidae) and Edestidae are assigned to the superfamily Edestoidea, the former containing genera such as Helicoprion and Parahelicoprion, and the latter containing genera such as Edestus. The family Helicampodontidae has been used for genera that do not closely resemble typical members of either of these two groups,[6] and the family Lestrodontidae has been proposed for the genus Lestrodus.[7] The superfamily Eugeneodontoidei (traditionally Caseodontoidea)[8] includes the families Caseodontidae and Eugeneodontidae, which were smaller and less-specialized than the edestoids.[3]

Some members of the superfamily Edestoidea are probably the largest marine animals of their time, though the body length estimates for both genera are somewhat speculative due to both only being known from skulls and teeth.[9] The Late Carboniferous Edestus has been estimated to reach exceed 6.7 metres (22 ft) in length, with some Early Permian Helicoprion suggested to be over 7.6 metres (25 ft) long by some estimates.[10][11][12] Eugeneodonts were predatory, with eugeneodontoids likely being generalist feeders and some edestoids being specialized for hunting cephalopods.[1][3][12]

Taxonomy

The list below shows taxa included within Eugeneodontiformes.[13]

References

  1. ^ a b Lebedev, O.A. (2009). "A new specimen of Helicoprion Karpinsky, 1899 from Kazakhstanian Cisurals and a new reconstruction of its tooth whorl position and function". Acta Zoologica. 90: 171–182. doi:10.1111/j.1463-6395.2008.00353.x. ISSN 0001-7272.
  2. ^ Tapanila L.; Pruitt J.; Pradel A.; Wilga C.; Ramsay J.; Schlader R.; Didier D. (2013). "Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion". Biology Letters. 9 (2) 20130057. doi:10.1098/rsbl.2013.0057. PMC 3639784. PMID 23445952.
  3. ^ a b c Zangerl, R. (1981). Handbook of Paleoichthyology. Volume 3A. Chondrichthyes I. Paleozoic Elasmobranchi. Stuttgart: Gustav Fischer Verlag. ISBN 978-3-89937-045-4.
  4. ^ Hodnett, John-Paul M.; Elliott, David K. (December 2018). "Carboniferous chondrichthyan assemblages from the Surprise Canyon and Watahomigi formations (latest Mississippian–Early Pennsylvanian) of the western Grand Canyon, Northern Arizona". Journal of Paleontology. 92 (S77): 1–33. doi:10.1017/jpa.2018.72. ISSN 0022-3360.
  5. ^ Scheyer, Torsten M.; Romano, Carlo; Jenks, Jim; Bucher, Hugo (19 March 2014). "Early Triassic Marine Biotic Recovery: The Predators' Perspective". PLOS ONE. 9 (3) e88987. Bibcode:2014PLoSO...988987S. doi:10.1371/journal.pone.0088987. PMC 3960099. PMID 24647136.
  6. ^ a b c Lebedev, O. A.; Itano, W. M.; Johanson, Z.; Alekseev, A. S.; Smith, M. M.; Ivanov, A. V.; Novikov, I. V. (2022). "Tooth whorl structure, growth and function in a helicoprionid chondrichthyan Karpinskiprion (nom. nov.) (Eugeneodontiformes) with a revision of the family composition". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 113 (4): 337–360. doi:10.1017/S1755691022000251.
  7. ^ Lebedev, Oleg A.; Itano, Wayne M.; Duffin, Christopher J.; Ivanov, Alexander O. (2026). "The earliest stem edestoid (Eugeneodontiformes, Chondrichthyes) from the Viséan (lower Carboniferous) of Tula Region, Central Russia, and a revision of Edestoidea". Canadian Journal of Zoology. 104: 1–24. doi:10.1139/cjz-2025-0140. ISSN 0008-4301.
  8. ^ Van der Laan, Richard (2018-10-11). "Family-group names of fossil fishes". European Journal of Taxonomy (466). doi:10.5852/ejt.2018.466. ISSN 2118-9773.
  9. ^ Gayford, Joel H.; Engelman, Russell K.; Sternes, Phillip C.; Itano, Wayne M.; Bazzi, Mohamad; Collareta, Alberto; Salas‐Gismondi, Rodolfo; Shimada, Kenshu (2024). "Cautionary tales on the use of proxies to estimate body size and form of extinct animals". Ecology and Evolution. 14 (9). doi:10.1002/ece3.70218. ISSN 2045-7758. PMC 11368419. PMID 39224151.
  10. ^ Tapanila, Leif; Pruitt, Jesse (2019-09-04). "Redefining species concepts for the Pennsylvanian scissor tooth shark, Edestus". PLOS ONE. 14 (9) e0220958. Bibcode:2019PLoSO..1420958T. doi:10.1371/journal.pone.0220958. ISSN 1932-6203. PMC 6726245. PMID 31483800.
  11. ^ Engelman, Russell K. (2023). "A Devonian Fish Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes for Dunkleosteus terrelli (Placodermi: Arthrodira)". Diversity. 15 (3): 318. doi:10.3390/d15030318. ISSN 1424-2818.
  12. ^ a b Tapanila, Leif; Pruitt, Jesse; Wilga, Cheryl D.; Pradel, Alan (2020). "Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition". The Anatomical Record. 303 (2): 363–376. doi:10.1002/ar.24046. ISSN 1932-8494. PMID 30536888.
  13. ^ Ginter, M.; Hampe, O.; Duffin, C. (2010). Handbook of Paleoichthyology. Volume 3D. Chondrichthyes. Paleozoic Elasmobranchi: Teeth. Munich: Verlag Dr. Friedrich Pfeil. ISBN 978-3-89937-116-1.
  14. ^ a b c Lebedev, O. A.; Itano, W. M.; Duffin, C. J.; Ivanov, A. O. (2026). "The earliest stem edestoid (Eugeneodontiformes, Chondrichthyes) from the Viséan (lower Carboniferous) of Tula Region, Central Russia, and a revision of Edestoidea". Canadian Journal of Zoology. doi:10.1139/cjz-2025-0140.
  15. ^ da Silva Santos, Rubens "Paleoictiofáunula da Formação Pedra de Fogo, Bacia do Parnaiba, NE do Brasil: II. Eugeneodontida-Agassizodontidae." Anais da Academia Brasileira de Ciências 66.4 (1994): 413-424.
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