Heterodontus, DE BLAINVILE, 1816

Kriwet, Jürgen, Nunn, Elizabeth V. & Klug, Stefanie, 2009, Neoselachians (Chondrichthyes, Elasmobranchii) from the Lower and lower Upper Cretaceous of north-eastern Spain, Zoological Journal of the Linnean Society 155 (2), pp. 316-347 : 320-322

GENUS HETERODONTUS DE BLAINVILE, 1816

Type species: Squalus philippi Bloch & Schneider, 1801 (junior synonym of Squalus portujacksoni Meyer, 1793 ). Extant in Australian temperate to subtropical waters to a depth of at least 275 m ( Compagno, 2001).

Remarks: The separation of heterodontid genera in the Late Jurassic is based on postcranial and dental characters ( Kriwet & Klug, 2004). Important differ- Description: The lateral tooth is large and mesiodistally elongated. It is curved, with a cambered, but not cuspidate crown, and has a well-marked transverse crest that rises in the central part to a barely differentiated cusp. A prominent ornamentation of enameloid ridges originates from the crest. The root is thin with a flat basal face and without nutritive groove.

Remarks: This tooth only has been identified to generic level, due to prospective revision of the genus that is currently being conducted by J. P. Biddle (pers. comm., 2004). Four Heterodontus species occur in the Early Cretaceous: H. carerens Kriwet (1999a) from the Barremian of Alcaine, Province of Teruel, northeastern Spain, H. canaliculatus (Egerton, in Dixon, 1850) from the Albian–Turonian of England and France, H. polonicus Rees, 2005 from the Valanginian of Poland and H. upnikensis ( Dalinkevicus, 1935) from the Albian and Cenomanian of Lithuania and France. The tooth from the lower Barremian of Aguilón differs from most known Heterodontus species in its occlusal ornamentation but resembles those of H. carerens , to which it is tentatively assigned. The Aguilón tooth is of similar age.

ORDER ORECTOLOBIFORMES APPLEGATE, 1972

FAMILY GINGLYMOSTOMATIDAE GILL, 1862