Rucervus is a 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...

 of deer

Deer

Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

 from India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, Nepal

Nepal

Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...

, Indochina

Indochina

The Indochinese peninsula, is a region in Southeast Asia. It lies roughly southwest of China, and east of India. The name has its origins in the French, Indochine, as a combination of the names of "China" and "India", and was adopted when French colonizers in Vietnam began expanding their territory...

, and the Chinese

People's Republic of China

China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...

 island Hainan

Hainan

Hainan is the smallest province of the People's Republic of China . Although the province comprises some two hundred islands scattered among three archipelagos off the southern coast, of its land mass is Hainan Island , from which the province takes its name...

. They are threatened

Threatened species

Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

 by habitat loss and hunting, and one species has already gone extinct.

They were previously thought to be members of the genus Cervus

Cervus

Cervus is a genus of deer that primarily are native to Eurasia, although one species occurs in northern Africa and another in North America. In addition to the species presently placed in this genus, it has included a whole range of other species now commonly placed in other genera, but some of...

, but were moved to Rucervus based mainly on morphological

Morphology (biology)

In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 differences. Based on genetic

Genetics

Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

 evidence, the Eld's Deer should be moved back to Cervus, while the two last species remain in Rucervus or –less likely– could be moved to Axis.

Species

Following the third edition of Mammal Species of the World

Mammal Species of the World

Mammal Species of the World, now in its 3rd edition, is a standard reference work in zoology giving descriptions and bibliographic data for the known species of mammals.An updated Third Edition of Mammal Species of the World was published late in 2005:...

from 2005, three species are placed in Rucervus, but it has been suggested that the Eld's Deer should be split into two species.

• Rucervus duvaucelii - Barasinga or Swamp Deer
• Rucervus eldii - Eld's Deer or Brow-antlered Deer
• Rucervus schomburgki - Schomburgk's Deer (extinct, 1938)

Furthermore, it has also been suggested that the Eld's Deer should have its own genus, Panolia, and is closer to Père David's Deer

Père David's Deer

Père David's Deer, Elaphurus davidianus, also known as the Milu , is a species of deer known only in captivity. It prefers marshland, and is believed to be native to the subtropics of China. It grazes on a mixture of grass and water plants. It is the only extant member of the genus Elaphurus...

.