Lithornis celetius is a member of the Lithornithidae

Lithornithidae

Lithornithidae are a family of palaeognathous birds from the early Tertiary of the northern hemisphere.-Species:The family was erected by Peter Houde in 1988. It includes the genera Lithornis, Paracathartes, and Pseudocrypturus...

 family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

, which was alive during the late Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

.

Description

Lithornis celetius was of average size in its genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

. It is from the Bangtail Quarry, Sedan Quadrangle, Park County, Montana

Montana

Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

, USA, and was described by Peter Houde (1988). It is from the Fort Union Formation

Fort Union Formation

The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane....

, which is earliest Tiffanian, Late Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

. The type fossil is USNM 290601.

Etymology

Celetius is derived from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 word keletion a race horse for which the type locality is also named.