A new Neopterygian fish form the Late Jurassic Ameghino (=Nordenskjold) Formation.

GOUIRIC-CAVALLI, SOLEDAD; BIGURRARENA-OJEDA, MAURICIO; CARIGLINO, BÁRBARA; IGLESIAS, ARI ; REGUERO, MARCELO

Congreso; SCAR OPEN SCIENCE CONFERENCE 2020; 2020

Scientific Committee on Antarctic Research

A new Jurassic neopterygian fish is presented on the basis of an almost complete specimen from the early Tithonian (Late Jurassic) Ameghino Formation in the Argentine Antarctic Sector (Antarctic Peninsula). Preliminary study of the material suggests this is a new species of Dapediiformes ?deep-bodied neopterygian fishes?. Dapediids as a whole are yet poorly sampled in formal phylogenetic analyses but to date, they are considered as stem-holostean fishes or the sister group of ginglymodians [Semionotiformes + Lepisosteiformes]. Moreover, the establishment of apomorphic characters for the members of the group is difficult. The specimen presented herein shares some similarities with the genus Dapedium (e.g., body-shape, dorsal fin, scales). Besides its importance as the first Dapediiformes described from Gondwana, this specimen adds information relative to the anatomy of these group of fishes, their diversity, ecology and paleobiogeography. Furthermore, the study of this fossil will increase the understanding of phylogenetic relationships among neopterygians fishes.