Caseodontidae

Caseodontidae
Temporal range: 315.2–247.2 Ma Early Carboniferous to Early Triassic
Life restoration of Caseodus, the type genus
The skull of Ornithoprion, an aberrant caseodont
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Holocephali
Order: †Eugeneodontida
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]

  1. ^ "Caseodontidae". Mindat.org. Retrieved 21 August 2024.
  2. ^ a b "Caseodontidae". Global Biodiversity Information Facility (GBIF). Retrieved 21 August 2024.
  3. ^ a b c Zangerl, Rainer (1 January 1981). Chondrichthyes 1: Paleozoic Elasmobranchii (Handbook of Paleoichthyology). Friedrich Pfell. ISBN 978-3899370454.{{cite book}}: CS1 maint: date and year (link)
  4. ^ a b Mutter, Raoul; Neuman, Andrew (10 June 2008). "Jaws and dentition in an Early Triassic, 3-dimensionally preserved eugeneodontid skull (Chondrichthyes)". Acta Geologica Polonica. 58: 223–227.
  5. ^ a b c Mutter, Raoul J.; Neuman, Andrew G. (2008). "New eugeneodontid sharks from the Lower Triassic Sulphur Mountain Formation of Western Canada". Geological Society, London, Special Publications. 295 (1): 9–41. Bibcode:2008GSLSP.295....9M. doi:10.1144/sp295.3. ISSN 0305-8719.
  6. ^ Alexander, Richard R. (1981). "Predation Scars Preserved in Chesterian Brachiopods: Probable Culprits and Evolutionary Consequences for the Articulates". Journal of Paleontology. 55 (1): 192–203. ISSN 0022-3360. JSTOR 1304340.