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[dinosaur] Saltasaurine titanosaur from Angostura Colorada Formation in Argentina

Ben Creisler

A new paper. Apparently the taxon has not been named.

Virginia Zurriaguz, Agustín Martinelli, Guillermo W. Rougier & Martín D. Ezcurra (2017)
A saltasaurine titanosaur (Sauropoda: Titanosauriformes) from the Angostura Colorada Formation (upper Campanian, Cretaceous) of northwestern Patagonia, Argentina.
Cretaceous Research (advance online publication)
doi: http://dx.doi.org/10.1016/j.cretres.2017.03.016


We describe the first saltasaurine sauropod of the Angostura Colorada Formation.
The saltasaurine from the Angostura Colorada Formation is more closely related to Saltasaurus loricatus and Rocasaurus muniozi than to Neuquensaurus australis.
The specimen described here shows extreme pneumaticity of the tail, indicating a considerable posterior expansion of abdominal air sac, even invading the chevrons. This is the first record of pneumatized chevrons among sauropodomorphs.


Saltasaurine titanosaurs are characterized by their relatively small size compared to other sauropods, extreme postcranial pneumaticity, and dermal armour covering the body. This group has been reported in the Upper Cretaceous of the Lecho, Allen, and Anacleto formations of Argentina. We describe here a new saltasaurine specimen (MACN-Pv RN 233) from the Campanian of the Angostura Colorada Formation (Río Negro Province) that is represented by eight caudal vertebrae and six osteoderms. This specimen is described in detail and its phylogenetic relationships with the other three known saltasaurines, as well as its implications to the knowledge of caudal vertebra and osteoderm anatomy, are discussed. Our results place MACN-Pv RN 233 more closely related to Saltasaurus loricatus and Rocasaurus muniozi than to Neuquensaurus australis. MACN-Pv RN 233 possesses a combination of features that differ from other saltasaurines, but because of the fragmentary nature of the specimen we decided for the sake of taxonomic stability to not erect a new taxon. This specimen shows the first unambiguous evidence of chevron pneumatisation for a sauropodomorph, implying a broader osteological invasion of the diverticula from the abdominal air sac than previously thought for this group of dinosaurs. MACN-Pv RN 233 preserves two osteoderm morphotypes, one similar to those reported for Neuquensaurus australis and Saltasaurus loricatus. This new specimen expands the distribution of the group to a new geological unit and increases the dinosaur diversity known for the Angostura Colorada Formation.