JesÃs Reolid, F. Javier Cardenal, MatÃas Reolid & Emilio Mata (2020)
3D Imaging of southernmost Triassic archosaur footprints from Europe (Southern Spain).
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 JaÃn (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).
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Roy M. Farman and Phil R. Bell (2002)
Australia's earliest tetrapod swimming traces from the Hawkesbury Sandstone (Middle Triassic) of the Sydney Basin.
Journal of Paleontology (advance online publication)
DOI:
https://doi.org/10.1017/jpa.2020.22 https://www.cambridge.org/core/journals/journal-of-paleontology/article/australias-earliest-tetrapod-swimming-traces-from-the-hawkesbury-sandstone-middle-triassic-of-the-sydney-basin/2C787D68A8F2F300B2111A0E68E5981CThe Hawkesbury Sandstone (Hawkesbury Series, Sydney Basin) on the southeastern coast of New South Wales, Australia, preserves a depauperate but important vertebrate tetrapod body-fossil record from the Early and Middle Triassic. As with many fossil sites around the world, the ichnological record has helped to shed light on the paleoecology of this interval. Herein, we investigate historical reports of a trackway pertaining to a putative short-tailed reptile found at Berowra Creek in the 1940s. Reinvestigation of the surviving track-bearing slabs augmented by archival photographs of the complete trackway, suggests that these impressions, which consist primarily of didactyl tracks (plus less common monodactyl and tridactyl traces), represent the earliest example of a swimming tetrapod found in Australia. Another isolated specimen (possibly from a nearby locality at Annangrove) appears to represent similar didactyl swim traces of a second, larger individual. Although the identities of the trackmakers are unknown, the Berowra Creek individual had an estimated body length of between ~80 cm (short-coupled) and 1.35 m (long-coupled), and produced the subaqueous trackway while travelling upslope (against the current) on a sandbar within a braided river system of the Hawkesbury Sandstone. These trackways partially resemble amphibian swim traces in the so-called Batrachichnus C Lunichnium continuum, but appear to represent a unique locomotion trace. This reanalysis of the Berowra Creek trackway provides insight into the locomotion of tetrapods of the Triassic Hawkesbury Series, which remains a poorly understood aspect of their life history.
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