Phylogenetic relationships of Unenlagiidae among Paraves (Dinosauria)

Abstract

In recent years, several studies on the osteology, myology and palaeobiology of southern paravians of the clade Unenlagiidae have considerably increased the information on the group. Nevertheless, their phylogenetic relationships in the theropod phylogenetic tree remain under discussion. Unenlagiids were proposed as early divergent members of Avialae or as members of Dromaeosauridae. Using as a base the most comprehensive known coelurosaurian data matrix (TWiG dataset), we aimed to test the phylogenetic affinities of unenlagiids. The dataset includes new available information, scorings based on direct observation of materials, and the addition of 15 taxa (including the Gondwanan Imperobator, Pamparaptor, Unenlagia paynemili and Overoraptor), and 23 characters. The phylogenetic trees obtained in the present analysis support the inclusion of all Gondwanan paravians in the clade Unenlagiidae, as early divergent members of Avialae, and outside of Dromaeosauridae. This emphasizes the importance of Unenlagiidae in interpreting the phylogenetic relationships and early evolution of avialans.