A new ichnosite and ichnogenus from the Lower Cretaceous Rio do Peixe Basin, Brazil, with novel insights into the evolution of Titanosauriformes

Sauropods were a successful group of herbivorous dinosaurs that colonised all continents throughout the Mesozoic. At first glance, the organisms in this group present a conservative shape of quadrupedal animals with elongated necks and tails. However, there was great diversification in the morphology of sauropods, which is still poorly understood in detail, especially during the Early Cretaceous. In this study, we describe a new ichnosite dated from the earliest stages of the Cretaceous of Brazil. The site includes a well-preserved trackway of a large sauropod dinosaur, with manus and pes prints, as well as tracks of theropods and indeterminate tetrapods. The sauropod trackway shows a unique set of characteristics that allowed the erection of a new ichnogenus and ichnospecies, Sousatitanosauripus robsoni igen. nov. et isp. nov. The probable trackmaker was a Titanosauriformes with a mosaic of basal and advanced features, bringing new insights into the diversity and evolution of the group.