The Popayán oldfield mouse (Thomasomys popayanus), also called the "Popayán Thomasomys", 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 present 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 southwestern and central western Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, at elevations from 1800 to 3200 m. It has been found in páramo

Páramo

The term páramo can refer to a variety of ecosystems. Some ecologists describe the páramo broadly as “all high, tropical, montane vegetation above the continuous timberline”. A more narrow term classifies the páramo according to its regional placement - specifically located in “the northern Andes...

, montane forest, and secondary forest

Secondary forest

A secondary forest is a forest or woodland area which has re-grown after a major disturbance such as fire, insect infestation, timber harvest or windthrow, until a long enough period has passed so that the effects of the disturbance are no longer evident...

. It was formerly considered a subspecies of T. aureus. T. nicefori (Thomas

Oldfield Thomas

Oldfield Thomas FRS was a British zoologist.Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and sub-species for the first time. He was appointed to the Museum Secretary's office in 1876, transferring to the Zoological Department in 1878...

, 1921), presently considered a synonym, will likely be raised to the status of a separate species. The specific name comes from the Colombian city of Popayán

Popayán

Popayán is the capital of the Colombian department of Cauca. It is located in southwestern Colombia between Colombia's Western Mountain Range and Central Mountain Range...

.