A giant chimaeroid fish from the Late Cretaceous of Antarctica.

GOUIRIC CAVALLI, SOLEDAD; CABRERA, DANIEL ALFREDO; O'GORMAN, JOSÉ; CORIA, RODOLFO; FERNÁNDEZ, MARTA; IGLESIAS, ARI; REGUERO, MARCELO

Zapala?Chocón

Jornada; XXVIII Jornadas Argentinas de Paleontología de Vertebrados; 2014

Holocephali (rat fishes, elephant fishes and their relatives) is a nowadays poorly diversified marine chondrichthyan clade that ranges from the Paleozoic to the Recent. It radiated during the Cretaceous but its diversity diminished during Cenozoic. The most distinctive character of the group is its statodont dentition. The dentition of chimaeroid fishes consists of two pairs of tooth plates in the upper jaw and one in the lower jaw. Chimaeroid tooth plates show hypermineralized tissue concentrated in areas called tritors, which never spread over the entire surface like other holocephalian fishes. Associated holocephalian dentitions are uncommon. The specimen reported here is three-dimensionally preserved and consists of a complete dentition represented by six large tooth plates. The material was collected in the late Campanian Herbert Sound Member of the Snow Hill Island Formation in the James Ross Island, Antarctica. According to the size of the tooth plates this specimen is one of the largest chimaeroid fish known. This finding represents the oldest and the most complete dentition of a holocephalian fish from Antarctica. Also, is the earliest record of the genus Edaphodon from the Antarctic continent. Moreover and according to a character combination the specimen could be a new species.