The titanosaurian dinosaur Atsinganosaurus velauciensis (Sauropoda) from the Upper Cretaceous of southern France: New material, phylogenetic affinities, and palaeobiogeographical implications

International audience; New remains of the titanosaurian sauropod Atsinganosaurus velauciensis from its Upper Cretaceous type horizon and type locality in Velaux-La Bastide Neuve (Bouches-du-Rhône Department, Provence) in southern France are described. This locality is considered to be upper Campanian (Argiles et Grès à Reptiles Formation, Aix-en-Provence Basin). The new material consists of skull fragments, including a partial braincase, isolated teeth, elements of the axial skeleton (cervical, dorsal and caudal vertebrae, ribs), and appendicular bones (scapula, humeri, ulna, metacarpals, ilia, ischia, femur, tibia, metatarsal) from at least 3 individuals. Histological investigation shows that the analysed individuals were mature. The emended diagnosis of Atsinganosaurus velauciensis includes a pubic peduncle of the ilium with a posterior concave surface in its distal half, surrounded by two sharp ridges. Equations for predicting body mass and size in sauropods suggest a body size up to 12 m and a body mass of at least 3.5–5 tonnes for the largest individuals.A phylogenetic analysis including 29 sauropod taxa was performed, with the European titanosaurs Atsinganosaurus, Ampelosaurus, Lirainosaurus, Lohuecotitan, Paludititan (Late Cretaceous) and Normanniasaurus (Early Cretaceous) all scored in the same analysis for the first time. Atsinganosaurus and Ampelosaurus form a clade that is phylogenetically proximal to Lirainosaurus within Lithostrotia – a clade here named Lirainosaurinae nov. – whereas Lohuecotitan and Paludititan form a clade towards the base of Lithostrotia. Normanniasaurus is resolved outside Lithostrotia, but within Titanosauria. From a palaeobiogeographical perspective, the phylogenetic results suggest that European titanosaurs belong to at least three distinct lineages and that two lithostrotian lineages were present during the latest Cretaceous in the European archipelago.