On the origin of the great white shark Carcharodon carcharias

The fossil record of modern sharks mainly consists of isolated teeth due to their poorly mineralized cartilaginous endoskeleton and a continuous tooth replacement that forms thousands of teeth during a sharks’ lifetime. As a result, phylogenetic analyses of extinct shark taxa are mostly based on isolated teeth and therefore often lead to ambiguous results. The great white shark Carcharodon carchariasis known since the late Miocene, a period in which a number of big lamniform sharks occurred, i.e., †Otodus megalodon,†Cosmopolitodus hastalisand †Carcharodon hubbelli, which vanished after the Plio-Pleistocene marine megafauna extinction (2.5 mya). The evolutionary history of the great white shark remains highly debated and two hypotheses have been proposed: (1) C. carcharias is closely related to the megatoothed sharks, including †O. megalodon; (2) C. carchariasshares a more recent common ancestor with mako sharks and descended from the broad toothed mako shark †C.hastalis. Although the latter hypothesis iscurrently favoured, the occurrence of a narrow-and a broad-toothed form of †C.hastalisfurther complicates the reconstruction of the evolutionary history of the great white shark. Here we report of an exceptional find of two well preserved shark skeletons of a juvenile (TL ~1.7m) and an adult (TL ~5m) †Cosmopolitodus hastalisfrom the late Miocene Pisco Formation of Peru, which display broad teeth. The presence of articulated jaws allowed us to reconstruct the tooth files of this species and thus a more accurate phylogenetic analysis of lamniform sharks based on dental characters could be performed, including extinct mako sharks, Isurus spp. Furthermore, geometric morphometric analyses are performed to visualize the morphospace occupation of Isurus,†Cosmopolitodus andCarcharodon.This combined approach allowedus to reconstruct the origin of Carcharodon carchariasand the dental transition from fossil mako sharks to the extant great white shark.