The Origin of Birds: Current Consensus, Controversy, and the Occurrence of Feathers

Abstract

AbstractResearch in the late 1900s has established that birds are theropod dinosaurs, with the discovery of feather preservation in non-avian theropods being the last decisive evidence for the dinosaur origin of this group. Partially due to the great interest in the origin of birds, more phylogenetic analyses of non-avian theropod dinosaurs have probably been published than any other group of fossil vertebrates. Despite a lot of uncertainty in the exact placement of many taxa and even some major clades, there is a remarkable consensus about the hierarchical position of birds (here used for the total group, Avialae) within theropod dinosaurs. Thus, birds are part of Paraves, together with such well-known theropod groups as dromaeosaurids and troodontids; Paraves are part of Maniraptora, which furthermore include Oviraptorosauria, Therizinosauria, and Alvarezsauroidea; Maniraptora belong to Maniraptoriformes, which also include Ornithomimosauria; Maniraptoriformes are a subclade of Coelurosauria, to which Tyrannosauroidea and some other basal taxa also belong; Coelurosauria are part of Tetanurae, together with Allosauroidea and Megalosauroidea; finally, Tetanurae are a subclade of Theropoda, which also include Ceratosauria and Coelophysoidea.KeywordsTheropodaAvialaeAvesPhylogenetic hierarchy