On the presence of the ichnogenus Procolophonichnium Nopcsa, 1923 in the Late Triassic of Brazil

Abstract

In some instances, additional interpretations of tetrapod footprints need to be made taking into consideration the paleoenvironmental context. The extramorphological variation of the tetrapod footprints can be related to the behavioural and/or substrate conditions. We investigated ten specimens from the Candelária Sequence (Hyperodapedon Assemblage Zone) from southern Brazil that preserve a set of pentadactyl footprints and trackways, in both convex and concave reliefs, previously referred to the ichnogenus Dicynodontipus. Pace angulation values are lower than predicted for Dicynodontipus (<110°) and within the standard for Procolophonichnium. The trackmaker is inferred to be a therapsid (cynodont). The environmental context of the lake system, present in Candelária Sequence, made it difficult for small organisms to move. The organisms slipped and sank, allowing for the preservation of footprints in epi- and hyporeliefs of some specimens.