''Eostrix'' is a genus of extinct primitive

owl Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...

s in the family Protostrigidae, along with ''Oligostrix'' and ''Minerva''. These owls date from the early

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, and

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

. They have been described based on fossil remains. The genus was created by

Pierce Brodkorb William Pierce Brodkorb (September 29, 1908, Chicago – July 18, 1992, Gainesville, Florida) was an American ornithologist and paleontologist. Interested in birds since childhood, he was taught to prepare birds at the age of 16. Later, he rec ...

in 1971 to place a fossil species known until that time as ''Protostrix mimica''. The following species are recognised: * ''E. mimica'' described in 1938 by

Alexander Wetmore Frank Alexander Wetmore (June 18, 1886 – December 7, 1978) was an American ornithologist and avian paleontologist. He was the sixth Secretary of the Smithsonian Institution. He was also an elected member of both the American Philosophical Soc ...

using hindlimb elements in Eocene strata in Wyoming. * ''E. martinellii'' was described in 1972 from a left

tarsometatarsus The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bird bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) a ...

(lower leg bone) recovered from an escarpment above the southeastern bank of Cottonwood Creek in

Fremont County, Wyoming Fremont County is a County (United States), county in the U.S. state of Wyoming. As of the 2020 United States census, the population was 39,234, making it the fifth-most populous county in Wyoming. Its county seat is Lander, Wyoming, Lander. T ...

by Jorge Martinelli on a field trip in 1970 under the auspices of the University of Kansas. The strata was a Lysite member of the Wind River Formation. Martinelli was studying paleontology at the University of Barcelona. Paleontologists Larry D. Martin and Craig Call Black from the University of Kansas Natural History Museum named it in his honour. The smaller of the two species, it was similar in size to the living

long-eared owl The long-eared owl (''Asio otus''), also known as the northern long-eared owlOlsen, P.D. & Marks, J.S. (2019). ''Northern Long-eared Owl (Asio otus)''. In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook o ...

(''Asio otus''). Differences in the trochleas (grooves) of the lower end of the tarsometatarsus set it apart from living owls, namely a groove in the trochlea for digit 2, a deeper posterior groove in a relatively narrow trochlea for digit 3, and an unusually rounded trochlea for digit 4. * ''E. vincenti'' described in 1980 by Colin Harrison from the early Eocene

London Clay The London Clay Formation is a Sediment#Shores and shallow seas, marine formation (geology), geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago) age which outcrop, crops out in the southeast of England. The London C ...

in England, known from pedal phalanx and proximal

bones. Some scholars think ''E. vincenti'' resembles '' Necrobyas'' more than ''Eostrix''. * ''E. tsaganica'' described in 2011 by

Evgeny Kurochkin Yevgeny Nikolayevich Kurochkin (Евгений Николаевич Курочкин; 12 July 1940 - 13 December 2011) was a Russian paleornithologist at the Paleontological Institute of the Russian Academy of Sciences. He served as President of ...

and Gareth J. Dyke, found in Mongolia. In 2016, Gerald Mayr described ''E. gulottai'' from the early Eocene Nanjemoy Formation in

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

. However, in 2022, Mayr, alongside Andrew C. Kitchener, moved '' 'E.' gulottai'' to the genus '' Ypresiglaux'' as the new combination ''Y. gulottai''.

References

Eocene birds of North America Protostrigidae Eocene birds of Europe Eocene animals of Asia {{Strigiformes-stub