REPTILES FROM LITHOGRAPHIC LIMESTONES OF THE LOS CATUTOS MEMBER (MIDDLE-UPPER TITHONIAN), NEUQUÉN PROVINCE, ARGENTINA: AN ESSAY ON ITS TAXONOMIC COMPOSITION AND PRESERVATION IN AN ENVIRONMENTAL AND GEOGRAPHIC CONTEXT

GASPARINI Z.; FERNÁNDEZ M.S.; DE LA FUENTE M. S.; HERRERA Y.; CODORNIÚ L.; GARRIDO A.

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2015 vol. 52 p. 1 - 28

0002-7014

The lithographic limestones of the Los Catutos Member (Vaca Muerta Formation, Neuquén Province, Argentina) (late middle-early upper Tithonian) bear a great diversity of marine reptiles. These deposits are unique in the Southern Hemisphere since the record of lithographic limestones from the Upper Jurassic is restricted to the Northern Hemisphere, particularly to Western Europe. Some European basins are very close in age (upper Kimmeridgian-lower Tithonian) but they do not reach the upper-middle Tithonian. As well, in the European basins the marine reptiles are mixed with continental biota whereas in Los Catutos Member the biota is exclusively marine, being the pterosaurs the only exception. The strictly marine biota is composed by ichthyosaurs, two different species of turtles, one crocodyliform and one plesiosaur. The taxonomic composition of Los Catutos Member is very similar to that found in Cerro Lotena (Portada Covunco Member, middle Tithonian) (Vaca Muerta Formation. These members share the same turtle species and one metriorhynchid genus, while ichthyosaurs only coincide in a family level. The knowledge resulting from the studies of marine reptiles of the Los Catutos Member, as well as those found in other localities of the Neuquén Basin, helped to fill an important gap in the evolution of the clades. On this regard, they represent the only known marine reptiles from Gondwana completing the Jurassic/Cretaceous transition, scarcely represented in the world.