The Hon Khoai squirrel (''Callosciurus honkhoaiensis'') is a species of

squirrel Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

in the family

Sciuridae Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the small island group of

Hon Khoai Hon Khoai (also called ''Ile Independence'' or ''Paulo Obi, Pulo Ubi)'' is a small archipelago located about 14 kilometers south from Ca Mau province, Vietnam. It is considered to be the southernmost point of Vietnam. The Hon Khoai islands consis ...

, which is located off the

Indochinese Peninsula Mainland Southeast Asia, also known as the Indochinese Peninsula or Indochina, is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west an ...

off the coast of south

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...

. It can be physically differentiated from other species of ''Callosciurus'' by the hairs at the tip of the tail being white with a black base, as well as the cream-colored

ventral side Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and feet. This species was likely separated from the mainland by the repeated

glaciations A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...

and interglaciations during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

. Its closest relative is the gray-bellied squirrel (''Callosciurus caniceps''), which it diverged from as early as the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58insular dwarfism Insular dwarfism, a form of phyletic dwarfism, is the process and condition of large animals evolving or having a reduced body size when their population's range is limited to a small environment, primarily islands. This natural process is disti ...

, it is much smaller than its mainland relative.

References

{{Taxonbar, from=Q58835703 Callosciurus Endemic_fauna_of_Vietnam Mammals described in 2018