A large Megaraptoridae (Theropoda: Coelurosauria) from Upper Cretaceous (Maastrichtian) of Patagonia, Argentina

Megaraptora is a theropod clade known from former Gondwana landmasses and Asia. Most members of the clade are known from the Early to Late Cretaceous (Barremian-Santonian), with Maastrichtian megaraptorans known only from isolated and poorly informative remains. The aim of the present contribution is to describe a partial skeleton of a megaraptorid from Maastrichtian beds in Santa Cruz Province, Argentina. This new specimen is the most informative megaraptoran known from Maastrichtian age, and is herein described as a new taxon. Phylogenetic analysis nested the new taxon together with other South American megaraptorans in a monophyletic clade, whereas Australian and Asian members constitute successive stem groups. South American forms differ from more basal megaraptorans in several anatomical features and in being much larger and more robustly built.

Automated summary

This study describes a partial skeleton of a megaraptorid from the Maastrichtian beds in Argentina, which is the most informative megaraptoran known from this time period and is identified as a new taxon. Phylogenetic analysis shows that South American megaraptorans form a monophyletic clade, while Australian and Asian members are stem groups. South American megaraptorans differ from more basal forms in several anatomical features and are larger and more robustly built.