A confuciusornithiform (Aves, Pygostylia)-like tarsometatarsus from the Early Cretaceous of Siberia and a discussion of the evolution of avian hind limb musculature

We describe a new isolated tarsometatarsus from the Early Cretaceous (Barremian-Aptian) Ilek Formation Shestakovo-3 locality in western Siberia. The new specimen represents a new taxon, Evgenavis nobilis, gen. et sp. nov., significantly increasing the Mesozoic avifauna from Russia. The specimen shares morphologies with a number of basal ornithothoracine taxa, but shows most similarity to the basal pygostylian Confuciusornis sanctus, the oldest...