New ichnological material from the Vera Formation (Los Menucos Complex, Triassic), Puesto Vera locality, Río Negro province, Argentina: a first account

CITTON, P.; DÍAZ-MARTÍNEZ, I.; DE VALAIS, S.; GONZÁLEZ, S.N.; GRECO, G.A.; FALCO, J.I.; CÓNSOLE-GONELLA, C.

Puerto Madryn

Otro; Reunión de Comunicaciones de la Asociación Paleontológica Argentina 2018,; 2018

Asociación Paleontológica Argentina

Los Menucos locality, in the north-western sector of the North Patagonian Massif (Río Negro province, Argentina), is prominent for having returned one of the most significant Triassic tetrapod ichnofauna of southern South America. A volcaniclastic succession mainly composed of dacitic to rhyolitic ignimbrites, mesosilicic lavas and subordinate sedimentary rocks, is exposed there. The tetrapod footprints are preserved in volcaniclastic and sedimentary strata of the Vera Formation, which constitutes, together with the overlying Sierra Colorada Formation, the Los Menucos Complex. The ichnofauna is mainly documented by small and large pentadactyl tracks respectively referable to as Dicynodontipus and Pentasauropus. The Dicynodontipus tracks originally came from the Tscherig quarry (west of Los Menucos town), while the Pentasauropus specimens came from the Yancaqueo quarry (east of Los Menucos town). In both cases, the exact stratigraphic position of the material, up to date, is unknown. Here, we present a new ichnosite from the thin sedimentary sequence of Puesto Vera Formation in its type locality. The material consists of 14 footprints of about 5 centimeters in overall length. The best-preserved tracks are pentadactyl with short and straight digits and show a central, well-developed heel-trace, resembling footprints commonly referred to as Dicynodontipus. The new finding is very important seeing that it allows, for the first time, positioning tetrapod tracks within the Vera Formation.