Diademodus
{{Short description|Extinct genus of cartilaginous fish}}
{{Automatic taxobox
| fossil_range = Late Devonian {{Fossil range|Frasnian|Famennian}}
| image = Diademodus hydei.png
| image_caption = Life restoration of Diademodus hydei
| taxon = Diademodus
| authority = Harris, 1951
| type_species = {{extinct}}Diademodus hydei
| type_species_authority = Harris, 1951
| subdivision_ranks = Species
| subdivision = *{{extinct}}D. hydei (Harris, 1951)
- {{extinct}}D. utahensis (Ginter, 2008)
- {{extinct}}D. dominicus (Roelofs et al., 2015)
}}
Diademodus is an extinct genus of phoebodontid elasmobranch that lived during the Late Devonian Period. The genus was first described by paleontologist John E. Harris based on a body fossil from the Cleveland Shale formation of Ohio. Teeth belonging to this genus have also been uncovered in Utah, Nevada, Western Australia, and Russia.{{Cite journal |last=Harris |first=John E. |date=1951 |title=Diademodus hydei, a new fossil shark from the Cleveland Shale. |url=https://zslpublications.onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.1951.tb00672.x |journal=Proceedings of the Zoological Society of London |language=en |volume=120 |issue=4 |pages=683–697 |doi=10.1111/j.1096-3642.1951.tb00672.x |issn=0370-2774|url-access=subscription }}{{Cite journal |last=Ginter |first=Michał |date=2008 |title=Devonian filter-feeding sharks |url=https://www.researchgate.net/publication/299023002 |format= |journal=Acta Geologica Polonica |volume=58 |issue=2 |pages=147–153}}{{Cite journal |last1=Trinajstic |first1=Kate |last2=Playton |first2=Ted |last3=Roelofs |first3=Brett |last4=Barham |first4=Milo |date=2015 |title=Upper Devonian microvertebrates from the Canning Basin, Western Australia |url=https://journals.pan.pl/dlibra/publication/94936/edition/81957 |journal=Acta Geologica Polonica |volume=65 |issue=1 |pages=69–101 |bibcode=2015AcGeP..65...69R |doi=10.1515/agp-2015-0003 |issn=0001-5709|hdl=20.500.11937/22966 |hdl-access=free }}{{Cite journal |last=Ivanov |first=A.O. |date=2022 |title=Fish Assemblages from the Middle–Upper Devonian of the Middle Urals, Russia |url=https://kpfu.ru/uz-eng-ns-2022-4-4.html |journal=Uchenye Zapiski Kazanskogo Universiteta. Seriya Estestvennye Nauki |language=en |volume=164 |issue=4 |pages=567–576 |doi=10.26907/2542-064x.2022.4.567-576 |issn=2542-064X}}
Description
According to Harris, Diademodus was a long, slender cartilaginous fish with a body length of up to {{convert|40|cm|ft|abbr=on}}. He also stated that Diademodus' body may have been slightly wider than it was tall, making it comparable to the modern catshark genus Scyliorhinus. Like most cartilaginous fish, its body was covered in tooth-like dermal denticles. These denticles were shorter near the animal's head and larger in rows along its lateral line. The tail lacked an exaggerated keel like that seen in the contemporaneous genus Cladoselache.
= Fins =
Diademodus possesses unusual fin morphology compared to other known chondrichthyans. Its pectoral fins are positioned unusually far back along the body, approximately {{convert|14|cm|in|abbr=on}} from the tip of its head. They are also extremely small, extending only {{convert|5.2|cm|in|abbr=on}} along the body and projecting {{convert|2.5|cm|in|abbr=on}} outward. The dorsal fin is located far forward, {{convert|2|cm|in|abbr=on}} ahead of the pectoral fin's front edge. Diademodus
= Teeth =
The teeth of Diademodus are very small, only about {{convert|1|mm|in|abbr=on}} wide at the base. These teeth contain nine to seventeen cusps, depending on the species, with the innermost and outermost cusps being significantly longer than the rest. Between the large cusps are at least three smaller cusps. Some teeth also have additional, minuscule cusps between the other cusps in the dentition.
Classification
Diademodus was originally classified as a member of the family Coronodontidae, a group that only included the genera Coronodus and Diademodus.{{Cite book |last=Zangerl |first=Rainer |title=Chondrichthyes I: Paleozoic Elasmobranchii |date=1981 |publisher=Fischer |isbn=978-3-437-30337-1 |series=Handbook of Paleoichthyology |volume=3a |location=Stuttgart New York |pages=68-69}} However, this classification was disputed in 2010, and Diademodus was tentatively reassigned to the family Phoebodontidae within the larger order Phoebodontiformes, potentially placing it alongside Phoebodus and Thrinacodus.{{Cite book |last=Ginter |first=Michał |title=Paleozoic Elasmobranchii: Teeth |last2=Hampe |first2=Oliver |last3=Duffin |first3=Christopher J. |date=2010 |publisher=F. Pfeil |isbn=978-3-89937-116-1 |series=Handbook of Paleoichthyology |location=München |pages=33-40}} The phoebodonts themselves are believed to represent early members of the subclass Elasmobranchii, which also includes modern sharks and rays.{{Cite journal |last=Frey |first=Linda |last2=Coates |first2=Michael |last3=Ginter |first3=Michał |last4=Hairapetian |first4=Vachik |last5=Rücklin |first5=Martin |last6=Jerjen |first6=Iwan |last7=Klug |first7=Christian |date=2019-10-02 |title=The early elasmobranch Phoebodus: phylogenetic relationships, ecomorphology and a new time-scale for shark evolution |url=https://royalsocietypublishing.org/doi/10.1098/rspb.2019.1336 |journal=Proceedings of the Royal Society B: Biological Sciences |volume=286 |issue=1912 |pages=20191336 |doi=10.1098/rspb.2019.1336 |pmc=6790773 |pmid=31575362}}
Paleobiology and paleoecology
Diademodus
References
{{Reflist}}
External links
- [https://sketchfab.com/3d-models/cmnh-5737-diademodus-hydei-holotype-7a4ee5820bb1445c8d4c75559d295f8d 3D model of scanned Diademodus hydei type specimen] at Sketchfab
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Category:Late Devonian cartilaginous fish
Category:Devonian cartilaginous fish of North America
Category:Devonian cartilaginous fish of Australia