A new basal rebbachisaurid (Sauropoda, Diplodocoidea) from the Early Cretaceous of the

CARBALLIDO, J.L.; SALGADO, L.; POL, D.; CANUDO, I.; GARRIDO, A.C.

Historical Biology

Taylor & Francis Ltd

Lugar: London; Año: 2012 vol. 24 p. 631 - 654

0891-2963

Despite that the origin of rebbachisaurids is retrieved as Late Jurassic is not until the upper Lower Cretaceous that this groupcan be recognised in the fossil record. The group is geographically restricted to Gondwana and Europe, and is particularlydiverse in the lower Upper Cretaceous of South America. In this subcontinent, Early Cretaceous forms are solely representedby Amazonsaurus and Zapalasaurus, being the former the putative basalmost rebbachisaurid known. Here, we provide arevised description of the sauropod from the Lohan Cura Formation (Aptian?Albian) that was previously identified asLimaysaurus sp. The new information available (mainly based on new elements) allows us to recognise a new taxon,Comahuesaurus windhauseni gen. et sp. nov. The phylogenetic analysis carried out retrieved this taxon as a relatively basalform of rebbachisaurid, well separated from Limaysaurinae. In this phylogenetic context, the new taxon revealed thepresence of a reduced hyposphene?hypantrum system in rebbachisaurids more derived than Histriasaurus, which iscompletely lost only in Limaysaurinae. Finally, a biogeographical scenario for rebbachisaurids is analysed through the use ofa Dispersal, Extinction and Cladogenesis analysis, which retrieves a South American origin for this linage, and a fastdispersion to Africa and Europe during the Hauterivian?Barremian.