| Caseodontidae Temporal range: Early Carboniferous to Early Triassic | |
|---|---|
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| Life restoration of Caseodus , the type genus | |
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| The skull of Ornithoprion , 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 | |
The Caseodontidae is an extinct family of eugeneodont holocephalans known from the late Paleozoic to earliest Mesozoic of Greenland, Canada and the United States. [1] [2] Members of the group are characterized by a reduced or absent palatoquadrate, 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 the neurocranium. [3] [4] Several genera are known from partial or complete body fossils. [3] [5]
Unlike the distantly related helicoprionids, members of this family crossed the Permian-Triassic boundary and persisted into the Olenekian stage of the Early Triassic, [5] after which they became extinct. It is hypothesized that in life caseodonts fed on hard-shelled prey such as brachiopods 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 the Carboniferous of Nebraska and Indiana, [3] deposits in East Greenland, [2] and from the Sulphur Mountain Formation of British Columbia, which is the last known appearance of the group. [5]
