Oioceros
Encyclopedia
Oioceros is an extinct genus of sheep from the late Miocene
. Its fossils have been found in Greece
, China
,, Iran
, and Africa
. It was first discovered by Wagner in 1857, and contains nine species, O. rothii, O. atropatenes, O. jiulongkouensis, O. noverca, O. robustus, O. stenocephalus, O. lishanensis, O. wegneri, and O. tanyceras. Former species include O. grangeri (Pilgrim, 1934), now recognized as the genus Sinomegoceros, and O. xiejiaensis (Li and Qui; 1980), now recognized as the genus Sinopalaeoceros.
Oioceros was somewhat resemblant of a gazelle
, and represents the world's oldest-known bovid
.
teeth, which were longer than the molars found in the latter. Pilgrim and Hopwood described the genus as being "small size with long slender muzzle; face bent down on basicranial axis either slightly or to a moderate extent; orbits with expanded orbital roof; horn-cores twisted counter-clockwise in a fairly close spiral of one or two revolutions, widely separate, tilted backward or fairly upright, divergent, with a cross-section almost circular or elliptical, keeled either anteriorly or posteriorly or both; dentition moderately hypsodont, premolar series rather long and slender, molars broad with ribs of medium strength" (Pilgrim and Hopwood, 1928, p. 24). The horn cores of Oioceros have a torsion
.
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
. Its fossils have been found in Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
,, Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
, and Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
. It was first discovered by Wagner in 1857, and contains nine species, O. rothii, O. atropatenes, O. jiulongkouensis, O. noverca, O. robustus, O. stenocephalus, O. lishanensis, O. wegneri, and O. tanyceras. Former species include O. grangeri (Pilgrim, 1934), now recognized as the genus Sinomegoceros, and O. xiejiaensis (Li and Qui; 1980), now recognized as the genus Sinopalaeoceros.
Oioceros was somewhat resemblant of a gazelle
Gazelle
A gazelle is any of many antelope species in the genus Gazella, or formerly considered to belong to it. Six species are included in two genera, Eudorcas and Nanger, which were formerly considered subgenera...
, and represents the world's oldest-known bovid
Bovid
A bovid is any of almost 140 species of cloven-hoofed ruminant mammal at least the males of which bear characteristic unbranching horns covered in a permanent sheath of keratin....
.
Description
In 1997, an almost complete skull of O. rothii proved that it was similar to Samotragus praecursor, with a short face, compared to its relatively long braincase, and isolated horn cores. However, unlike S. praecursor, O. rothii had a jaw of primarily premolarPremolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...
teeth, which were longer than the molars found in the latter. Pilgrim and Hopwood described the genus as being "small size with long slender muzzle; face bent down on basicranial axis either slightly or to a moderate extent; orbits with expanded orbital roof; horn-cores twisted counter-clockwise in a fairly close spiral of one or two revolutions, widely separate, tilted backward or fairly upright, divergent, with a cross-section almost circular or elliptical, keeled either anteriorly or posteriorly or both; dentition moderately hypsodont, premolar series rather long and slender, molars broad with ribs of medium strength" (Pilgrim and Hopwood, 1928, p. 24). The horn cores of Oioceros have a torsion
Torsion of curves
In the elementary differential geometry of curves in three dimensions, the torsion of a curve measures how sharply it is twisting. Taken together,the curvature and the torsion of a space curve are analogous to the curvature of a plane curve...
.
Species
- Oioceros rothii was first named by Wagner in 1857. He originally had the specimen he had found in Pikermi, Greece, under the name "Antilope rothii". In 1902, Gaillard reassigned the species to Oioceros rothii.
- Oioceros atropatenes was first named by Rodler & Weithofer in 1890.
- Oioceros jiulongkouensis was first named by G. Chen and W. Wu in 1976.
- Oioceros noverca was first named by Pilgrim in 1934.
- Oioceros robustus was first named by Chen and Wu in 1976.
- Oioceros stenocephalus was first named by Chen and Wu in 1976.
- Oioceros wegneri was first named by Andree in 1926. It possibly represents an entirely different genus of sheep.
Further reading
- Mammoths, Sabertooths, and Hominids by Jordi Agusti and Mauricio Anton. Published 2002, Columbia University PressColumbia University PressColumbia University Press is a university press based in New York City, and affiliated with Columbia University. It is currently directed by James D. Jordan and publishes titles in the humanities and sciences, including the fields of literary and cultural studies, history, social work, sociology,...
. ISBN 0231116403 - Classification of Mammals by Malcolm C. McKenna and Susan K. Bell. Published 1997, Columbia University PressColumbia University PressColumbia University Press is a university press based in New York City, and affiliated with Columbia University. It is currently directed by James D. Jordan and publishes titles in the humanities and sciences, including the fields of literary and cultural studies, history, social work, sociology,...
. ISBN 0231110138
External links
- Oioceros at the Paleobiology DatabasePaleobiology Database' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...
- Oioceras tanyceras at Zipcodezoo.com
- UAE Interact - A Walk Through Time