Mosasaurs (Reptilia) from the late Maastrichtian (Late Cretaceous) of northern Patagonia (Rio Negro, Argentina)

FERNÁNDEZ, MARTA; MARTIN, JIM; CASADÍO, SILVIO

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

Elsevier

Lugar: Amsterdam; Año: 2008 vol. 25 p. 176 - 186

0895-9811

A diverse assemblage of mosasaurs was recently recovered from the Jagu¨ el Formation (late Maastrichtian) exposed at three localities of northern Patagonia (Rý´o Negro, Argentina). Four taxa (three mosasaurines and a plioplatecarpine) have been identified, and three of these marine reptiles can be identified at lower taxonomic levels: Mosasaurus sp. aff. M. hoffmanni, Plioplatecarpus sp., and Prognathodon sp. These occurrences are significant because they represent the first diagnostic material at generic level exhumed from Patagonia and include one of the youngest mosasaurs found worldwide. One of the specimens described herein was found only 1.5 m below the Cretaceous/Tertiary boundary. Only mosasaurs from Antarctica found within a meter of the boundary are known to occur higher in the geologic section.