Caseodus

Caseodus Temporal range: Carboniferous - Early Triassic? 355–247.2  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Holotype of Caseodus basalis
Life reconstruction of Caseodus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Order:	† Eugeneodontiformes
Family:	† Caseodontidae
Genus:	† Caseodus Zangerl, 1981
Type species
Orodus basalis (Cope, 1894)
Species [1]
†C. basalisCope, 1894 †C. eatoniZangerl, 1981 †C. varidentis? Mutter & Neumann, 2008

Caseodus is an extinct genus of eugeneodont from the Carboniferous of what is now the Midwestern United States, ^[2] and potentially the Early Triassic of what is now British Columbia, Canada. ^[3] The genus contains two Carboniferous species, C. basalis and C. eatoni, which are differentiated by the anatomy of their teeth but are otherwise identical. ^{[2] [4]} A third species, C. varidentis, is known from the Early Triassic Sulphur Mountain Formation, ^[3] but due to its wildly different skull and tooth morphology it is questionable if it belongs in the genus. ^[5] The genus name is in honor of paleoichthyologist Gerard Case, ^[2] and the type species was originally placed in the genus Orodus . ^{[4] [6]}

Teeth of Caseodus basalis

All species in the genus grew to approximately 1–1.5 m (3.3–4.9 ft) in length. ^{[2] [3] [4]} The Carboniferous species had upper jaws which supported teeth and a row of fused teeth (termed a tooth-whorl) along the midline of the lower jaw. ^{[2] [5]} The Triassic species entirely lacked upper jaws and had an elongated projection, termed a rostrum, which extended from the lower jaw and supported the lower tooth-whorl. ^[5] Caseodus varidentis (if included in the genus) is one of the few eugeneodontid genera that survived the end-Permian mass extinction event, and is one of the last surviving genera of this clade. ^[3]

References

1. Cimimurri, D.J; Fahrenbach, M.D. (2002). "Chondrichthyes from the upper part of the Minnelusa Formation (Middle Pennsylvanian: Desmoinesian), Meade County, South Dakota" (PDF). Proceedings of the South Dakota Academy of Science. 81.
2. R., Zangerl (1981). Handbook of paleoichthyology. Vol. 3A. Chondrichthyes I (Paleozoic elasmobranchii). Gustav Fischer. ISBN   3-437-30337-6. OCLC   1116152115.
3. Mutter R.J., Neuman A.G. (2008): New eugeneodontid sharks from the Lower Triassic Sulphur Mountain Formation of Western Canada. In: Fishes and the Break-up of Pangaea. Cavin L, Longbottom A, Richter M, editors. Geol Soc London Spec Publ 295: 941
4. Ginter, Michał; Hampe, Oliver; Duffin, Christopher J. (2010). Handbook of paleoichthyology: teeth. München: F. Pfeil. p. 118. ISBN   978-3-89937-116-1.
5. Mutter, Raoul J.; Neuman, Andrew G. (2008-06-10). "Jaws and dentition in an Early Triassic, 3-dimensionally preserved eugeneodontid skull (Chondrichthyes)". Acta Geologica Polonica. 58 (2): 223–227.
6. Cope, E. D. (1894). New and little known Paleozoic and Mesozoic fishes. Vol. ser.2:v.9 (1884-1895). Philadelphia: Academy of Natural Sciences of Philadelphia. pp. 427–448.