New fossils of the giant pholidosaurid genus Sarcosuchus from the Early Cretaceous of Tunisia

Abstract

The Lower Cretaceous vertebrate assemblages from southeastern Tunisia contain one of the most diverse, unique and significant vertebrate faunas of this period in North Africa. The fossil record of crocodyliforms from these assemblages is becoming better understood with the increasing number of palaeontological discoveries that have been made over the past few years. However, very little data is available on the North Gondwanan pholidosaurid crocodyliform Sarcosuchus due to the paucity of material likely because of selective taphonomic factors. Here, I describe and figure new fossils of the pholidosaurid genus Sarcosuchus from Aptian-Albian deposits of the Tataouine Basin in southeastern Tunisia. These fossils include well-preserved dorsal osteoderms, which were found in anatomical connection, several isolated teeth and fragmentary remains mostly pertaining to the appendicular and axial skeletons. Anatomical studies and comparisons with other specimens have been performed, supporting the attribution of the material to the genus Sarcosuchus. I show that no attempt at a specific level can be made on the basis of the present fossils. The large size of the osteoderms and the stout conical teeth indicate that many Sarcosuchus individuals reached enormous body sizes.Sarcosuchus would have prospered in a flood dominated river-delta system that characterized the Tethyan margin of Gondwana by the end of the Lower Cretaceous. The abundant remains of diverse fish taxa including actinopterygians, sarcopterygians and chondrichthyans are indicative of a productive ecosystem, and further suggest that the diet of the Tunisian taxon included large bodied fish. This discovery provides a substantial addition to the extremely poor record of the North African crocodylomorphs with new insights into their palaeobiogeographic distribution, palaeoecology and extinction.