Swimming reptile prints from the Keuper facies (Carnian, Upper Triassic) of Los Gallegos new tracksite (Iberian Range, Valencia province, Spain)

Abstract

A new locality of Carnian reptile tracks (Upper Triassic) is described from the Manuel Sandstone Formation (Keuper facies). The track-bearing layer is located in the Los Gallegos creek (municipality of Cortes de Pallás, Valencia province) and the prints are preserved as natural casts. The tracks are isolated and, although there are certain alignments, these do not constitute trackways. Most of the prints are made up of sub-parallel digital marks. The number of digits and their size is variable, being tetradactyl the most complete ones. In some cases, the heel area has been preserved, although the impression of the V toe has never been so. No handprints have been found either. This preservation does not allow precise identification, although general characters as well as age suggest that these tracks may be related to the chirotheroid group and therefore, with archosauriform or archosaur crurotarsal reptiles. The characteristics of sediment, footprints and the presence of structures such as digit reflectures, Z-traces, posterior overhangs and longitudinal striations suggest that the ichnites were produced by swimming, totally or partially buoyant reptiles in a context dominated by a fluvial system with restricted marine influence during the Carnian Humid Episode.