ASPIDORHYNCHIFORMES FROM THE UPPER JURASSIC OF THE NEUQUEN BASIN, SOUTHERN SOUTH AMERICA

GOUIRIC CAVALLI, SOLEDAD

Viena

Congreso; 6th International Meeting on Mesozoic Fishes. Diversification and Diversity Patterns; 2013

Universitätt Wien and Naturhistorisches museum Wien

ASPIDORHYNCHIFORMES FROM THE UPPER JURASSIC OF THE NEUQUEN BASIN, SOUTHERN SOUTH AMERICA Soledad Gouiric Cavalli1 1 CONICET, División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo. UNLP, Paseo del Bosque s/n B1900FWA, La Plata, Argentina; e-mail: sgouiric@fcnym.unlp.edu.ar A unique family, Aspidorhynchidae, composes the order Aspidorhynchiformes; this group of fishes has a worldwide distribution. The family Aspidorhynchidae range in age from the Middle Jurassic to Upper Cretaceous. Aspidorhynchids form a monophyletic group with four nominal genera: Belonostomus, Aspidorhynchus, Vinctifer and Richmondichthys. This fishes are commonly recognized by the possession of elongate rostrum formed by fusion of both premaxillae, one accessory bone in the lower jaw: the predentary, triangular preopercle with the sensorial canal in posterior position, elongate (higher than wide) lateral flank scales, small and forked caudal fin, pectoral fins with few rays that are distally segmented. Although the family Aspidorhynchidae was erected at the end of the 19th century, the phylogenetic relationships of the Aspidorhynchidae within the neopterygians are still in debate. Some of this debate is due to the difficulties on polarizing some of the anatomical characters as well as different interpretation of some structures. The major understanding of the Jurassic members of the family surely can help to resolve its phylogenetic position. In South America the family is widely represented by the Cretaceous genus Vinctifer. In Argentina the family is almost exclusively represented in Jurassic marine deposits in several localities of the Vaca Muerta and Picún Leufú formations, although there is also reported from some Cretaceous continental deposits of Coli-Toro and Allen formations. The goal of the present contribution is to expand the knowledge of the Jurassic aspidorhynchids from the Neuquen Basin, analyzing and discussing many anatomical characters. Additionally, I hypothesized about the possible migration routes that were used by the fishes that inhabited the Neuquen Basin during the Late Jurassic (Tithonian).