Skull Anatomy and Pneumaticity of the Enigmatic Coelurosaurian Theropod Bicentenaria argentina.

FERNANDO E. NOVAS

The anatomical record

American Association for Anatomy

Año: 2019

1932-8494

The enigmatic basal coelurosaur Bicentenaria argentina is a small theropodthat comes from the Upper Cretaceous of Patagonia. It is constituted bymore than 130 elements, including cranial remains. These are represented byan incomplete snout, palate, dermatocranium, and lower jaws still in articulation.The skull material of Bicentenaria was preliminarily studied by previousauthors. In this study, we conducted a CT scan of the holotype of Bicentenaria,which allowed us to fully describe all preserved skull bones, including somepreviously unknown elements. The morphological analysis indicates thatBicentenaria shares many cranial features with other basal coelurosaurs ascompsognathids, Ornitholestes, and tyrannosauroids. Otherwise, results of thisanalysis show that Bicentenaria exhibits a set of traits unique to this taxon.Furthermore, several pneumatic recesses were closely matched with thosepneumatic features present in many derived coelurosaurs, particularlytyrannosauroids. This new information, together with future discoveries, willimprove our knowledge about the muscular correlates of Bicentenaria andother coelurosaurs, and may shed light about the phylogenetic relationships ofthis group.