Cuscomys 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 rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s found in the Andes

Andes

The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

 of Cusco in southern Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

. These relatively large chinchilla rat

Chinchilla rat

Chinchilla rats or chinchillones are members of the family Abrocomidae. This family has few members compared to most rodent families with only 9 known living species. They resemble Chinchillas in appearance, with a similar soft fur and silvery-grey color, but have a body-structure more like a...

s are dark grey with a distinct white line running from the crown to the nose. The genus was coined in 1999 when C. ashaninka was scientifically described, but later it was discovered that C. oblativus, a species traditionally placed in the genus Abrocoma

Abrocoma

Abrocoma is a genus of abrocomid rodents found in the Andes of South America, from southern Peru to central Chile. The genus contains eight species, most of which are found in isolated mountain ranges in northwestern Argentina.- Species :...

, actually belonged in Cuscomys. They are very poorly known, as C. ashaninka only is known from the holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

, while C. oblativus usually has been considered extinct, as it was only known from remains found in 1912, buried alongside people in ancient Inca

Inca civilization

The Andean civilizations made up a loose patchwork of different cultures that developed from the highlands of Colombia to the Atacama Desert. The Andean civilizations are mainly based on the cultures of Ancient Peru and some others such as Tiahuanaco. The Inca Empire was the last sovereign...

 tombs at the Machu Picchu

Machu Picchu

Machu Picchu is a pre-Columbian 15th-century Inca site located above sea level. It is situated on a mountain ridge above the Urubamba Valley in Peru, which is northwest of Cusco and through which the Urubamba River flows. Most archaeologists believe that Machu Picchu was built as an estate for...

 ruins. However, photos of a rodent taken at the ruins in late 2009 likely show this species. It is unclear if the Cuscomys truly are extremely rare, as they may be easily overlooked due to their remote distributions and arboreal habits.

Species

• Cuscomys ashaninka
  Cuscomys ashaninka
  The Asháninka Arboreal Chinchilla Rat is a large species of chinchilla rat from the Andes of far northern Cusco in Peru. It was only scientifically described in 1999. The animal has grey fur, with a white nose and lips, and a line of white fur running down its head...
  
  – Asháninka Arboreal Chinchilla Rat
• Cuscomys oblativus
  Cuscomys oblativus
  Cuscomys oblativus known as the Machu Picchu Arboreal Chinchilla Rat, is a large species of South American chinchilla rat, known from remains found in 1912, buried alongside people in ancient Inca tombs at Machu Picchu in Peru...
  
  – Machu Picchu Arboreal Chinchilla Rat