| Caseodontidae | |
|---|---|
 | |
| Life restoration ofCaseodus, the type genus | |
 | |
| The skull ofOrnithoprion, an aberrant caseodont | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Order: | †Eugeneodontiformes |
| Clade: | †Caseodontoidea |
| Family: | †Caseodontidae Zangerl, 1981 |
| Type genus | |
| Caseodus Zangerl, 1981 | |
| Type species | |
| Orodus basalis (=Caseodus basalis) Cope, 1894 | |
| Genera | |
TheCaseodontidae is an extinct family ofeugeneodontholocephalans known from the latePaleozoic to earliestMesozoic ofGreenland,Canada and theUnited States.[1][2] Members of the group are characterized by a reduced or absentpalatoquadrate, elongate upper and mandibular rostra, and bulbous,crushing dentition, including a small symphyseal whorl of teeth on the lower jaw and batteries of teeth fused directly to theneurocranium.[3][4] Several genera are known from partial or complete body fossils.[3][5]
Unlike the distantly relatedhelicoprionids, members of this family crossed thePermian-Triassic boundary and persisted into theOlenekian stage of theEarly Triassic,[5] after which they became extinct. It is hypothesized that in life caseodonts fed on hard-shelled prey such asbrachiopods due to their crushing tooth batteries,[4] and it has been proposed that the elongated rostra on the upper and lower jaws of some genera was an adaptation for prying prey off of the seabed.[6] Well preserved specimens are known from theCarboniferous ofNebraska andIndiana,[3] deposits inEast Greenland,[2] and from theSulphur Mountain Formation ofBritish Columbia, which is the last known appearance of the group.[5]
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