''Leptomeryx'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

ruminant Ruminants (suborder Ruminantia) are ungulate, hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by Enteric fermentation, fermenting it in a specialized stomach prior to digestion, principally ...

of the family Leptomerycidae, endemic to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

during the

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

through

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

38–24.8 Mya, existing for approximately . It was a small

deer Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...

-like ruminant with somewhat slender body. Leptomeryx BW

Fossil distribution

Sites and species recovered: *Titus Canyon,

Inyo County, California Inyo County () is a county in the eastern central part of the U.S. state of California, located between the Sierra Nevada and the state of Nevada. In the 2020 census, the population was 19,016. The county seat is Independence. Inyo County is ...

''(L.blacki)'' ~30.6—33.9 Ma. *UNSM Sx-8 (Orella C),

Sioux County, Nebraska Sioux County is a County (United States), county in the U.S. state of Nebraska. As of the 2010 United States Census, the population was 1,311. Its county seat is Harrison, Nebraska, Harrison. Sioux County is included in the Scottsbluff, Nebrask ...

''(L. elissae)'' ~33.9—24.8 Ma. *Anxiety Butte,

Saskatchewan, Canada Saskatchewan ( ; ) is a province in western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on the south by the U.S. states of Montana and North Dak ...

''(L. sp., L. evansi)'' ~38—24.8 Ma. *Calf Creek,

, ''(L. mammifer)'' ~38—33.3 Ma. *Toadstool Park,

''(L. speciosus)'' ~37.2—33.3 Ma. *Medicine Pole Hills,

Bowman County, North Dakota Bowman County is a county in the U.S. state of North Dakota. As of the 2020 census, the population was 2,993. Its county seat is Bowman. History The legislature of the Dakota Territory designated Bowman (named for Edward M. Bowman, a member o ...

''(L. yoderi)'' ~38—33.9 Ma.Paleobiology database: Medicine Pole Hills collection
/ref>

References

* Webb, S.D., 1998. Hornless ruminants. pp. 463–476 ''in'' C.M. Janis, K.M. Scott, and L.L. Jacobs (''eds.'') ''Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals.'' Cambridge University Press, Cambridge. * Heaton, T.H. and Emry, R.J., 1996

pp. 581–608 ''in'' D.R. Prothero and R.J. Emry (''eds.'') ''The Terrestrial Eocene-Oligocene Transition in North America.'' Cambridge University Press, Cambridge. * Eocene even-toed ungulates Oligocene even-toed ungulates Eocene mammals of North America Oligocene mammals of North America White River Fauna Eocene United States Paleogene United States Eocene genus first appearances Chattian genus extinctions Fossil taxa described in 1853 Prehistoric even-toed ungulate genera {{paleo-eventoedungulate-stub