The first record of the chimaeroid genus Edaphodon (Chondrichthyes, Holocephali) from Antarctica (Snow Hill Formation, Late Cretaceous, James Ross Island)

GOUIRIC-CAVALLI S , CABRERA D , CIONE A , O´GORMAN J , CORIA R , FERNÁNDEZ M , IGLESIAS A , REGUERO M

Awckland

Simposio; 2014 SCAR OPEN SCIENCE CONFERENCE; 2014

SCAR

Holocephali (rat fishes, elephant fishes and relatives) is a relatively poorly diversified marinechondrichthyan clade that ranges from the Paleozoic to the Recent. It radiated during theCretaceous but its diversity diminished during the Cenozoic. The most distinctive character of thegroup is its bradyodont dentition. The dentition of chimaeroid fishes consists of two pairs of toothplates in the upper jaw and one pair in the lower jaw. Chimaeroid tooth plates showhypermineralized tissue concentrated in areas called tritors, which never spread over the entireocclusal surface like in other holocephalian fishes. Associated holocephalian dentitions areuncommon. The specimen reported here is three-dimensionally preserved and consists of analmost complete dentition represented by five big sized tooth plates. The material was collected inthe late Campanian Herbert Sound Member of the Snow Hill Island Formation in the James RossIsland, Antarctica. According to the size of the tooth plates, this specimen is one of the largestchimaeroid fish known. Also, this finding represents the oldest and the most complete dentition ofa holocephalian fish from the Southern Hemisphere and the first record of the genus Edaphodonfrom the continent. Moreover and according to a character combination the specimen could be anew species.