''Emydops'' is an extinct genus of

dicynodont Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivorous animals with a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typica ...

therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented mor ...

from the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Pale ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

. ''Emydops'' was first named by South African paleontologist

Robert Broom Robert Broom FRS FRSE (30 November 1866 6 April 1951) was a British- South African doctor and palaeontologist. He qualified as a medical practitioner in 1895 and received his DSc in 1905 from the University of Glasgow. From 1903 to 1910, ...

in 1912 when he described ''Emydops minor''. In the following years, the genus grew to include thirteen species. Many of these species were erected on the basis of differences in the teeth and the positioning of the

frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music *The Front (band), an American rock band signed to Columbia Records and active in the 1980s and ea ...

and

parietal bone The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named ...

s. A 2008 study narrowed ''Emydops'' down to two species, ''E. arctatus'' (first described by English paleontologist

Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Ow ...

as ''Kistecephalus arctatus'' in 1876) and the newly described ''E. oweni''. Both species of ''Emydops'' are small. The skull of ''Emydops'' was 5 cm (2 in) long. Tusks are present in most skulls, but some lack them. The eye sockets are positioned far forward in the skull and face somewhat forward and upward. A wide area on the lower jaw called the lateral

dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

shelf is another distinguishing feature of the genus. The temporal regions behind the eyes are large, and the back of the skull is wide and square-shaped. 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 ...

specimen of ''E. oweni'' is unusual in that it has two pairs of tusks. The second pair of tusks is not seen in any other dicynodont, and is a feature unique to the specimen. The extra tusks are considered a

pathological Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in t ...

feature; they are thought to have been the result of a mutation in the individual and are not considered a defining characteristic of the species.

References

Dicynodonts Guadalupian synapsids Lopingian synapsids of Africa Fossil taxa described in 1912 Taxa named by Robert Broom Lopingian genus extinctions Anomodont genera {{anomodont-stub