Rhinoceros unicornis was the
scientific name used by
Carl Linnaeus in 1758 who
described a rhinoceros with one horn. As
type locality, he indicated Africa and India. He described two species in India, the other being
Rhinoceros bicornis, and stated that the Indian species had two horns, while the African species had only one. The Indian rhinoceros is a single
species. Several specimens were described since the end of the 18th century under different
scientific names, which are all considered
synonyms of
Rhinoceros unicornis today: •
R. indicus by
Cuvier, 1817 •
R. asiaticus by
Blumenbach, 1830 •
R. stenocephalus by
Gray, 1867 •
R. jamrachi by
Sclater, 1876 •
R. bengalensis by Kourist, 1970
Etymology The
generic name rhinoceros is derived through Latin from the , which is composed of (
rhino-, "of the nose") and (
keras, "
horn") with a horn on the nose. The name has been in use since the 14th century. The
Latin word
ūnicornis means "one-horned".
Evolution Ancestral rhinoceroses first diverged from other
perissodactyls in the
Early Eocene. Mitochondrial DNA comparison suggests the ancestors of modern rhinos split from the ancestors of
Equidae around 50 million years ago. The extant family, the Rhinocerotidae, first appeared in the
Late Eocene in
Eurasia, and the ancestors of the extant rhino species dispersed from Asia beginning in the
Miocene. The last common ancestor of living rhinoceroses belonging to the subfamily Rhinocerotinae is suggested to have lived around 16 million years ago, with the ancestors of the genus
Rhinoceros diverging from the ancestors of other living rhinoceroses around 15 million years ago. The genus
Rhinoceros has been found to be overall slightly more closely related to the
Sumatran rhinoceros (as well as to the extinct
woolly rhinoceros and the extinct Eurasian genus
Stephanorhinus) than to living African rhinoceroses, though there appears to have been
gene flow between the ancestors of living African rhinoceroses and the genus
Rhinoceros, as well as between the ancestors of the genus
Rhinoceros and the ancestors of the woolly rhinoceros and
Stephanorhinus. |style=font-size:100%;line-height:80%}}The earliest fossils of the genus
Rhinoceros date to the Late Miocene, around 8–9 million years ago. The divergence between the Indian and
Javan rhinoceros is estimated to have occurred around 4.3 million years ago. They also appear to have ranged as far south as
Tamil Nadu in India, based on
subfossil remains as recent as the
Neolithic. A
Late Pleistocene-aged partial fossil skeleton of
R. unicornis was described from
Kanchanaburi, Thailand in 2018. Several fossil
Rhinoceros species from South Asia, such as
R. palaeindicus &
R. sivalensis (from the
Late Pliocene or
early Pleistocene of
Nahan),
R. deccanensis (from the
Pleistocene of
Karnataka) and
R. namadicus (from the Pleistocene of
Madhya Pradesh) are potentially synonymous with
R. unicornis. == Characteristics ==