Tail anatomy of Buitreraptor gonzalezorum (Theropoda, Unenlagiidae) and comparisons with other basal paravians

NOVAS, FERNANDO E.; BRISSÓN EGLI, FEDERICO; MOTTA, MATÍAS J.

CRETACEOUS RESEARCH (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2018 vol. 83 p. 168 - 181

0195-6671

Tail anatomy of unenlagiid theropods remains poorly known. The most complete and informative taxon of this family is Buitreraptor gonzalezorum from the Upper Cretaceous of Rio Negro province, Argentina. The aim of the present contribution is to carry out an analysis of the tail anatomy of Buitreraptor based on its holotype and a newly collected specimen as well. 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.