''Pseudocrypturus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of extinct

paleognathous Palaeognathae (; ) is a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contain ...

bird. One species is known, ''Pseudocrypturus cercanaxius''. It is a relative of such modern birds as

ostrich Ostriches are large flightless birds of the genus ''Struthio'' in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There a ...

es. It lived in the early

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

. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

fossil is in the collection of the Smithsonian's

National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with ...

. It has catalog number USNM 336103. It was collected from the Fossil Butte Member,

Green River Formation The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine ...

Lincoln County, Wyoming Lincoln County is a county in the U.S. state of Wyoming. As of the 2020 United States Census, the population was 19,581. Its county seat is Kemmerer. Its western border abuts the eastern borders of the states of Idaho and Utah. History Lincol ...

, USA.Houde, Peter W. (1988)

Taxonomy

''Pseudocrypturus'' means false

tinamou Tinamous () form an order of birds called Tinamiformes (), comprising a single family called Tinamidae (), divided into two distinct subfamilies, containing 46 species found in Mexico, Central America, and South America. The word "tinamou" comes ...

. The species name cercanaxius comes from ancient Greek words , tail, and , worthless, in reference to the rudimentary

pygostyle Pygostyle describes a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main compo ...

of this species.

Footnotes

References

* * {{Taxonbar, from=Q7254714 Bird genera Eocene genus extinctions Paleognathae Paleogene birds of Europe Paleogene birds of North America Fossil taxa described in 1988