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| Wiki.Ichthys/Diademodus Temporal range: Late Devonian
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Clade: | †Phoebodontiformes |
| Genus: | †Diademodus Harris, 1951 |
| Type species | |
| †Diademodus hydei Harris, 1951
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| Species | |
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Diademodus is an extinct genus of phoebodontiform elasmobranch with fossils from the late Devonian of Ohio, Utah, Nevada, and Western Australia. The genus is known mostly from fossilized teeth and one body impression.[1][2][3]
Diademodus would have been a relatively small shark with a long, slender body estimated to have reached 40 centimeters (1.3 feet) in length. It had notably reduced pectoral fins, a single anteriorly placed dorsal fin, and features indicative of a heterocercal caudal fin. The teeth of Diademodus were approximately 1 millimeter wide and had three to four main cusps. Additionally, it possessed at least three intermediate cusplets between each cusp, an uncommon trait in other phoebodontiformes. It is theorized to have been a relatively poor swimmer and may have lived near the sea floor.[1]
Species
editDiademodus hydei
editThe type species, based on a well-preserved body impression from the Cleveland Shale of Ohio. The specific epithet is in honor of the late Dr. Hyde, a professor of geology at Case Western Reserve University. The teeth of D. hydei were initially described as having ten cusps in total, with the two middlemost and outermost cusps being the largest. However, the middlemost cusps were reinterpreted as a single large cusp in 2008. The fossil contains fish scales in the gut area, indicating that the animal was most likely piscivorous.[1][2]
Diademodus utahensis
editThis is the second species described, from the Pilot Shale of Utah and Nevada. D. utahensis only possessed one middlemost tooth cusp as opposed to D. hydei’s initially proposed two. One recovered tooth has an additional, asymmetrical cusplet, making it the first species of Diademodus known to exhibit heterodonty. It has been suggested that the teeth of D. utahensis were too delicate to grasp prey and were instead used in filter feeding.[2]
Diademodus dominicus
editThe third species described, from the Virgin Hills Formation of Western Australia. It is the first species discovered outside of Laurussia. The specific epithet honors Mr. Dominicus 'Tim' Mueller, M.Sc. This species' teeth are characterized by three large cusps like that of D. utahensis, but with overall tooth anatomy that more closely resembles D. hydei.[3]
References
edit- ^ a b c Harris, John E. (1951). "Diademodus hydei, a new fossil shark from the Cleveland Shale". Proceedings of the Zoological Society of London. 120 (4): 683–697. doi:10.1111/j.1096-3642.1951.tb00672.x. ISSN 0370-2774.
- ^ a b c Ginter, Michał (2008). "Devonian filter-feeding sharks". Acta Geologica Polonica. 58 (2): 147–153.
- ^ a b Trinajstic, Kate; Playton, Ted; Roelofs, Brett; Barham, Milo (2015). "Upper Devonian microvertebrates from the Canning Basin, Western Australia". Acta Geologica Polonica. 65 (1): 69–101. Bibcode:2015AcGeP..65...69R. doi:10.1515/agp-2015-0003. ISSN 0001-5709.
External links
editCategory:Phoebodontiformes Category:Frasnian life Category:Famennian life Category:Late Devonian cartilaginous fish Category:Devonian cartilaginous fish of North America Category:Devonian cartilaginous fish of Australia Category:Fossil taxa described in 1951