3D Imaging of southernmost Triassic archosaur footprints from Europe (Southern Spain)

Abstract

The application of 3D photogrammetric models to the analysis of rauisuchian archosaur footprints of the Middle-Upper Triassic of the south Iberian palaeomargin improves the knowledge and interpretation of the behaviour of rauisuchian archosaurs that inhabited this area. Two outcrops rich in footprints were scanned at Santisteban del Puerto and Cambil in Jaen (SE Spain). The footprints of Santisteban del Puerto consist of three subparallel concave impressions including two long lateral traces, and a shorter medial one. The footprints of Cambil are preserved as convex hyporeliefs, counter-moulds, at the bottom of inverted strata and record manus and pes impressions. The 3D photogrammetric models provide new data sets such as depth distribution maps, contour line maps, and topographic profiles of the footprints that implement the interpretation obtained during fieldwork. These are useful tools for the study, preservation, and dissemination of such outcrops. Digitally generated depth distribution maps display darker (blue) colours for the most depressed areas of the traces. The contour line maps and digital elevation models of the footprints improve the understanding of the locomotion of the tracemaker. The footprints of Cambil and Santisteban del Puerto represent the only ichnological record of Triassic terrestrial vertebrates in the southern Iberian Peninsula, and the southernmost record of trace fossils of the Triassic in Europe. These outcrops also provide information about different locomotion styles of Triassic archosauromorphs including swimming/floating of bipeds (Santisteban del Puerto) and walking of quadrupeds (Cambil).