The Ashaninka oldfield mouse (Thomasomys onkiro) is a species 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....

 in the family Cricetidae

Cricetidae

The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, and New World rats and mice...

. It is known only from a single locality (which includes Otishi National Park

Otishi National Park

The Otishi National Park is a protected area in Peru located in the Junín Region , Junín Province and Satipo Province, Río Tambo District and in the Cusco Region , La Convención Province, Echarate District. It protects Southwest Amazon moist forests at lower elevations and Peruvian Yungas at...

) in the Cordillera Oriental of the 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....

vian 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...

, in montane forest at an elevation of 3350 m. It has terrestrial habits. The common name refers to the Asháninka

Asháninka

The Asháninka or Asháninca are an indigenous people living in the rainforests of Peru and in the State of Acre Brazil....

, the largest indigenous group of the Peruvian Amazon.