The first fossil owls (Aves: Strigiformes) from the Paleogene of Asia and a review of the fossil record of Strigiformes

The fossil record of owls (Strigiformes) is one of the most extensive among the neornithine birds, yet at the same time largely restricted geographically to Europe and North America. Various fossil owls are known from the Paleocene (ca. 60 Ma) to Recent. Here we present the first taxonomic description of new species of Paleogene owls from Asia, two new taxa from the Eocene and Oligocene of Mongolia. The anatomy of Heterostrix tatsinensis gen. et sp. nov., represented by a complete Early Oligocene tarsometatarsus, sheds light on the evolution of perching adaptations in these birds and expands the family diversity of this order. Eostrix tsaganica sp. nov. from the Early Eocene extend the known range of the protostrigid genus Eostrix into Asia (the other known species come from Europe and western North America). The paper also provides a review of the fossil record of owls, which gives evidence for the Late Cretaceous evolutionary radiation of this lineage. In spite of the absence of specimens from the Mesozoic, fossil owl collector-effort (since the 1860s) suggests that, in contrast to many other avian clades, the fossil record of these birds is complete enough for biological signal to be extracted.