Matías J. Motta, Federico Brissón Egli & Fernando E. Novas (2017)
Tail anatomy of Buitreraptor gonzalezorum (Theropoda, Unenlagiidae) and comparisons with other basal paravians.
Cretaceous Research (advance online publication)
Tail anatomy of unenlagiid theropods remains poorly known. The most complete and informative taxon of this family is Buitreraptor gonzalezorum from the late Cretaceous of Rio Negro province, Argentina. The aim of the present contribution is to carry out an analysis of the tail anatomy in Buitreraptor, based on the holotype and a newly collected specimen. Similarities shared by Buitreraptor, Rahonavis, Anchiornis and Archaeopteryx include: mid-caudal vertebrae with postzygapophyses longer than prezygapophyses, and mid-caudal centra with a system of lateral laminae and concavities. Preservation of paravian skeletons, as well as muscular reconstruction, indicate the presence of two different functional sections of the tail. This contribution sheds light on paravian tail evolution and provides new data on tail changes that occurred along the theropod line towards modern birds.