Pathological features and insect boring marks in a crocodyliform from the Bauru Basin, Cretaceous of Brazil

Abstract

The type specimen of Stratiotosuchus maxhechti (DGM 1477-R), a baurusuchid mesoeucrocodylian from the Bauru Basin (Upper Cretaceous of Brazil) displays some abnormalities that are here described. The holotype was examined macroscopically and compared with other skeletal elements of S. maxhechti and Baurusuchus salgadoensis (UFRJ DG 288-R). After this analysis, the elements with signs of alterations were subjected to a computed tomography (CT) scan exam which gave more information about them. The medial and proximal thirds of the right metacarpal V show an extensive bone growth, which modified the normal form of this element. The left metatarsals I and II exhibit an abnormal bone callus covering part of the medial third of the distal end. Based on their morphology these features are regarded as the result of two injuries of distinct natures. In the right metacarpal V, the presence of a large bone callus and a fracture, with two possible causes: post-traumatic infection or tumour. In the metatarsal I and II a case of stress fracture with a marked bone callus. Additionally, insect boring marks in the left ulna and right and left tibia of the same specimen were observed, which could be confused with pathologies. These bone changes may provide additional clues about the palaeoenvironment, such as habitat conditions, in which the specimen studied here lived. © 2011 The Linnean Society of London.