Dinosaur tracks with skin impressions in the La Buitrera Paleontological Area (Candeleros Formation, Cenomanian), Río Negro Province, Argentina

Abstract

The La Buitrera Paleontological Area, in the north of the Río Negro Province, Argentina, preserves the uppermost section of the Cenomanian Candeleros Formation, as well as a rich vertebrate fauna that inhabited the Kokorkom Desert paleo-erg. Candia Halupczok et al. (2017) reported tracks found on wet and dry interdune. New evidence from 2020 to 2022 fieldtrips enabled the recognition of tracks in cross-section in non-channelized ephemeral fluvial dominated facies within the main aeolian setting located in the vicinity of the wettest recorded area of the La Buitrera Locality: the Cañadón de las Tortugas. The cross-section tracks commonly identified in these facies are from 30 to 75 cm long and 20–30 cm deep. Some of them preserve thin and shallow structures in the filling of the original track wall interpreted here as traces of the trackmaker integument. Specimens preserve two kinds of skin impressions. The first ones are parallel, mostly oblique striations, which sometimes cross each other at a high angle, produced by the pes during penetration and withdrawal from the substrate. The second ones are subrounded to polygonal, here interpreted as scale traces of the sole foot. Two clear, subtriangular to curved, and elongated, claw impressions are recorded in one track that allow us to relate it with a sauropod trackmaker.