Under my skin: dinosaur tracks with skin impressions at the La Buitrera Paleontological Area (Candeleros Formation, Cenomanian), Río Negro Province, Argentina

DÍAZ MARTÍNEZ, IGNACIO; APESTEGUÍA, SEBASTIÁN; DE VALAIS, SILVINA; RIGUETTI, FACUNDO; PÉREZ MAYORAL, JOAQUÍN; VEIGA, GONZALO D.

Congreso; Reunión de Comunicaciones de la Asociación Paleontológica Argentina; 2022

The La Buitrera Paleontological Area (LBPA) preserves fossilized remains of theKokorkom Desert at the uppermost section of the Candeleros Formation, as well as arich vertebrate fauna. In 2017 Candia and collaborators reported tracks found on wetand dry interdune. New evidence from 2020 and 2022 fieldtrips enabled the recognitionof tracks both in cross-section and plan view in non-channelized ephemeral fluvialdominated facies within the main aeolian setting. The cross-section tracks commonlyidentified in these facies are 15 cm long and 5-10 cm deep. Some of them preserve thinand shallow structures in the filling of the original track wall interpreted here as tracesof the trackmaker integument. Specimens preserve two kinds of skin impressions. Thefirst ones are parallel, mostly oblique striations which sometimes cross each other at ahigh angle, produced by the pes during penetration and withdrawal from the substrate.The second ones directly under the foot are subrounded to polygonal, here interpreted asscale traces of the pes ventral pad. Two clear, subtriangular to curved, and elongated,claw impressions are recorded in one track that allow us to relate it with a sauropodtrackmaker. The tracks preserved in plan view are exposed in at least two levels, one ofthem correlated with the cross-section tracks. Tracks found in the study area areassociated with non-channelized ephemeral fluvial sandy facies from a fluvialdominated depositional stage and were located in the vicinity of the wettest recordedarea of the La Buitrera Locality: the Cañadón de las Tortugas.