The morphofunctional design of Montealtosuchus arrudacamposi (Crocodyliformes, Upper Cretaceous) of the Bauru Basin, Brazil

Abstract

Montealtosuchus arrudacamposi, a Peirosauridae from the Upper Cretaceous of the Bauru Basin, was a Crocodyliformes of terrestrial habits. The fossils analyzed in this study belong to the pectoral girdle (scapula and coracoid) and anterior appendicular skeleton (humerus, radius, ulna, carpals, radiale, ulnale, metacarpals and phalanges). In this study we infer the locomotion habits of M. arrudacamposi. A morphometric, morphofunctional and 3D reconstruction of the elements of the pectoral girdle and the anterior limbs of M. arrudacamposi were performed. For a better understanding of the most plausible pectoral girdle and anterior limb posture, the studied bones were virtually disarticulated and articulated on 3D reconstruction. The herein results obtained indicate the structures present a relatively thin and elongated aspect, thus allowing an interpretation that M. arrudacamposi possessed more slender anterior limbs than living crocodyliforms. This condition allowed for an adducted stance and cursorial habits that would enable movement through terrestrial environments for prey searching.