Comments on the Morphology of Basal Paravian Shoulder Girdle: New Data Based on Unenlagiid Theropods and Paleognath Birds

In 1976 John Ostrom published an enlightening paper about the anatomical transformations in shoulder girdle and forelimb elements along origin of birds. Most his ideas were based on comparing Archaeopteryx lithographica with extant New World vulture Cathartes aura . offered innovative range movements function wing basal bird Further, he explored that may have occurred at early stages evolution flight established several hypothetical steps toward acquisition flapping modern Since then, however, our understanding paravian diversity anatomy has increased dramatically. Based novel information derived from recent experiments, currently available evidence paravians, present aims to review some important topics pectoral related origins. a brief analysis osteology myology paleognath Rhea americana is also included aim test whether Ostrom’s still remain valid under this new context, phylogenetic frameworks.