New cranial remains of titanosaurian sauropod dinosaurs from the Late Cretaceous of Fox-Amphoux-Métisson (Var, SE France)

Abstract

The Fox-Amphoux Syncline of the Aix Basin (SE France) has yielded a diverse Late Cretaceous vertebrate assemblage, including several taxa of dinosaurs. Here, we report on cranial material of titanosaurian sauropods, which consist of a partial braincase, two fragmentary skull roofs, and nine teeth, from the Métisson locality (Var Department). The braincase differs from those found previously in Europe (i.e., Ampelosaurus atacis, Lirainosaurus astibiae, and an unnamed juvenile skull from Romania) as well as from other titanosaurian braincases in having a groove that extends along the ventral surface of the occipital condyle neck (this feature may be autapomorphic). One of the fragmentary skull roofs may belong to the same taxon, whereas the other suggests the presence of a second titanosaur at Métisson very close to Ampelosaurus. Two dental morphologies are present in the sample; one of them includes teeth of different sizes. We suggest that this could be accounted for by age differences within a single taxon, or be due to different positions in the tooth row. The presence of a new, still unnamed titanosaurian taxon in the Ibero-Armorican Island supports previous works indicating a high titanosaurian diversity during the Campanian-Maastrichtian in southern Europe.