Postcranial remains of Knoetschkesuchus guimarotae (Atoposauridae, Crocodylomorpha) from the Late Jurassic of Portugal and its locomotor behaviour

Abstract

Small bodied material of crocodylomorphs from the Late Jurassic of Portugal is rare and provenances are limited to just a few sites. Furthermore, most recovered material consists of single isolated skeletal elements. In this study a specimen comprising over fifty postcranial elements from the Porto de Barcas Member of the Lourinhã Formation near Baleal, Peniche, Portugal, is discussed. Micro CT-scans were performed in order to describe, measure and analyse the fragile specimen. Based on osteoderm morphology and comparisons to referred material of Knoetschkesuchus guimarotae, the specimen was ascribed to this taxon. Linear measurements of this specimen and referred material were used in a morphometric analysis to infer the locomotor behaviour of K. guimarotae. This quantitative approach indicates a semi-aquatic lifestyle, like present-day crocodylians. Due to the consistent postcranial osteology within Atoposauridae, this conclusion might extend to the entire family. Further research on this specimen could potentially reveal more about its lifestyle within the deltaic environment of the Lusitanian Basin during the Late Jurassic.