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Comahuesaurus, new rebbachisaurid sauropod from Early Cretaceous of Argentina

From: Ben Creisler

A new taxon in the new issue of Historical Biology:

José Luis Carballido, Leonardo Salgado, Diego Pol, José Ignacio Canudo
& Alberto Garrido (2012)
A new basal rebbachisaurid (Sauropoda, Diplodocoidea) from the Early
Cretaceous of the Neuquén Basin; evolution and biogeography of the
Historical Biology 24(6): 631-654

Despite that the origin of rebbachisaurids is retrieved as Late
Jurassic is not until the upper Lower Cretaceous that this group can
be recognised in the fossil record. The group is geographically
restricted to Gondwana and Europe, and is particularly diverse in the
lower Upper Cretaceous of South America. In this subcontinent, Early
Cretaceous forms are solely represented by Amazonsaurus and
Zapalasaurus, being the former the putative basalmost rebbachisaurid
known. Here, we provide a revised description of the sauropod from the
Lohan Cura Formation (Aptian–Albian) that was previously identified as
Limaysaurus 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 basal form of rebbachisaurid,
well separated from Limaysaurinae. In this phylogenetic context, the
new taxon revealed the presence of a reduced hyposphene–hypantrum
system in rebbachisaurids more derived than Histriasaurus, which is
completely lost only in Limaysaurinae. Finally, a biogeographical
scenario for rebbachisaurids is analysed through the use of a
Dispersal, Extinction and Cladogenesis analysis, which retrieves a
South American origin for this linage, and a fast dispersion to Africa
and Europe during the Hauterivian–Barremian.