Analysis identifies unique trace fossils in Carnian deposits, suggesting swimming behavior of small tetrapods.
Small trace fossils are recorded in the top and the bottom of a thin sandstone bed located in the upper part of the K1 unit (lower Carnian, Upper Triassic), in the Tabular Cover. In the top surface, two trace fossils have been identified: a tridactyl digitigrade elongated scratch mark with preserved triangular claws (20 mm long and 19 mm wide), with two lateral elongated (30 mm) and curved marks are located back to the margins of the tridactyl footprint, and a longitudinal furrow (185 mm long and 3 mm wide). In the bottom surface there are two autopodium impressions preserved as convex hyporeliefs, counter moulds (45 mm long, 26 mm wide, and 18 mm long, 14 mm wide). They are tridactyl, elongated scratch marks, located very close and forming an angle of 48º. Trace fossils are interpreted as produced on the bottom by small tetrapods when floating in a low energy shallow environment. In the top surface correspond to the right hindlimb and the tail. In the bottom surface the scratch marks are more elongated and may be related to pes and manus. The potential authors are uncertain. This is a new example of swimming trace fossil for the Carnian deposits of the southern and eastern Iberia.
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Cardenal et al. (2025) studied this question.
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