Preliminary taphonomic studies of terrestrial vertebrate remains at Arroyo Pilmatué, Mulichinco Formation, Las Lajas, Neuquén Basin

PINO, DIEGO; CORIA, RODOLFO; DÍAZ MARTINEZ, IGNACIO; TUNIK, MAISA; BELLARDINI, FLAVIO; BAIANO, MATTIA; WINDHOLZ, GUILLERMO

San Luis

Otro; Reunión de Comunicaciones de la Asociación Paleontológica Argentina; 2017

Asociación Paleontológica Argentina- Universidad Nacional de San Luis

A new association of continental vertebrate remains found in the lower section of the Mulichinco Formation (Valanginian), 10 kilometers north of Las Lajas, have permitted initial taphonomic studies.The facies associations evidence the deposit of fluvial channel, with lateral migration bars and scarce development of floodplains. The fossils are found in a tabular medium-to coarse-grained sandstone bed of 1.5-2 meters thick, with thin interbedded of conglomerate and well-sorted very coarse-grained sandstones (facies a). The remains are semi-articulated, disarticulated, and associated or non-associated. The long bones are principally NE-SW oriented, with post-mortem modifications such as low to moderate abrasion, surface modification suggests weathering stage1 to 2, and fragile deformation recognized in 60% of the specimens. According to these taphonomic features, the larger specimens are considered to be parautochthonous in origin, although with no significant carcass transportation. Dispersions of remains would be due to intermittent energy pulses, which are inferred from gradation very coarse-grained sandstones to well-selected conglomerates. Small skeletal elements were easily transported, so there are not associated with semi-articulated elements of the main carcass.