Remains of Sauropoda (Reptilia, Saurischia) in the Lower Cretaceous (Upper Hauterivian/Lower Barremian) Limestones of SW Istria (Croatia)

摘要

Remains belonging to sauropod dinosaurs have recently been discovered in Upper Hauterivian/Lower Barremian (Lower Cretaceous) limestones of SW Istria (Croatia). The material consists of a complete cervical vertebra, a nearly complete cervical centrum, fragments of possible cervical ribs, three partial dorsal and five more or less incomplete caudal vertebrae, parts of caudal neural spines, a chevron, the distal part of a femur, the proximal portion of a tibia and other fragments of bones. The bones were collected randomly from the sea bottom, therefore despite the fact that they come from the same outcrop, the same level and probably the same bed, they cannot be assigned with certainty to the same taxon. Their vastly different sizes indicate the presence of several individuals while different morphologies suggest the probable presence of more than one taxon. The complete cervical and the anterior to mid-caudal vertebrae present a more strict affinity with Brachiosauridae, a proximal cervical centrum resembles those of “Chondrosteosaurus”, and a caudal neural spine is similar to those of the camarasaurids. The dorsal vertebrae have peculiar features (a very tall neural arch, well developed laminar complex, etc.) and characters suggesting their assignation to basal Titanosauriformes and, possibly, to Diplodocimorpha. A posterior dorsal vertebra testifies the presence of a new Diplodocimorph similar to Rebbachisaurus but more primitive.