Mystiornis

Mystiornis is an extinct genus of bird which existed in what is now western Siberia, Russia during the early Cretaceous period (Barremian/Aptian age). It is known from an isolated metatarsus found in the Shestakovo-1 locality of southern Western Siberia. It was named by Evgeny N. Kurochkin, Nikita V. Zelenkov, Alexandr O. Averianov and Sergei V. Leshchinskiy in 2011, and the type species is Mystiornis cyrili.[1] While most recent studies place it as an Enantiornithine, specifically an Avisaurid, the authors note that the placement in both groups is tentative and further material will be required to make a firm decision on placement due to the unusual features of the existing material.[2]

Mystiornis Temporal range:
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Avialae
Clade:	†Enantiornithes
Family:	†Avisauridae
Genus:	†Mystiornis Kurochkin et al., 2011
Species:	†M. cyrili
Binomial name
†Mystiornis cyrili Kurochkin et al., 2011

Based on the strongly shortened metatarsal II and orientation of throchleae, Mystiornis had diving adaptations similar to that of Gansus and Neogaeornis. It was the size of a thrush.[1]