A new taxon of birds (Aves) from the Early Cretaceous of Western Siberia, Russia

摘要

In recent decades numerous findings, mostly from the Early Cretaceous of China, have changed traditional conceptions about the diversity and evolution of the most ancient Aves. Findings of Mesozoic birds in Russia are extremely rare. Here we describe a new bird from the Lower Cretaceous (Barremian-Aptian, Ilekskaya Svita) Shestakovo-1 locality (southern Western Siberia, Russia), that has also yielded dinosaurs, mammals, crocodiles, pterosaurs and lizards. Mystiornis cyrili gen. et sp. nov. is based on an isolated metatarsus which displays a mosaic of morphological features allowing us to create a new order, Mystiornithiformes. Mystiornis has a fully consolidated (oraithurine-like) gracile metatarsus with a primitive coplanar arrangement of the metatarsals, three separate proximal articular facets, and a uniquely located distal interosseal canal. It also displays diving adaptations previously documented only in Ornithurae.