Abstract
The Chichínales Formation, on the city of General Roca, Río Negro province, Argentina, is a lithostratigraphic unity, with a rich vertebrate fossil deposit. Thus, the majority of the findings so far consist of mammals, some few avians and turtles, and remains of crocodyliform osteoderms. It is believed that the age of the formation is Lower Miocene (Colhuehuapense), based on its associate…