''Nephelomys keaysi'', also known as Keays's oryzomysMusser and Carleton, 2005, p. 1149 or Keays's rice rat, is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

in the genus '' Nephelomys'' of family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At over 870 species, it is either the largest or second-largest family ...

.Weksler et al., 2006, p. 18 It is found from southeastern

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

to northern

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

on the eastern slope of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

Yungas The Yungas ( Aymara ''yunka'' warm or temperate Andes or earth, Quechua ''yunka'' warm area on the slopes of the Andes) is a bioregion of a narrow band of forest along the eastern slope of the Andes Mountains from Peru and Bolivia, and extends i ...

humid forest at altitudes of 1000 to 2600 m. Although its continued existence is not in serious danger and it is listed as "

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

", destruction of its habitat may pose a threat to some populations. In 1900,

Joel Asaph Allen Joel Asaph Allen (July 19, 1838 – August 29, 1921) was an American zoology, zoologist, mammalogy, mammalogist, and ornithology, ornithologist. He became the first president of the American Ornithologists' Union, the first curator of birds and ma ...

described two rodents from

Juliaca Juliaca (; Quechua language, Quechua and ) is the capital of San Román Province in the Puno Region of southeastern Peru. It is the region's largest city with a population of 276,110 inhabitants (2017 Peru Census, 2017). On the Altiplano, Juliaca ...

, Peru, at an altitude of on the basis of specimens collected in 1899 and 1900 by H. H. Keays. One he named, after Keays, ''Oryzomys keaysi'', and the other ''Oryzomys obtusirostris''. He considered the former to have no close relatives and the latter to be close to '' O. longicaudatus''.

Oldfield Thomas Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist. Career Thomas worked at the Natural History Museum, London, Natural History Museum on mammals, describing about 2,000 new species and subspecies for ...

, in reporting on some specimens from Peru, concurred with the latter allocation, but considered ''O. keaysi'' to be part of the group around '' O. albigularis'', and suggested that these should perhaps all be placed in the same species. After re-examining his specimens of ''O. obtusirostris'', Allen reclassified the animal to the genus ''

Zygodontomys ''Zygodontomys'' is a genus of rodent in the tribe Oryzomyini of the family Cricetidae. Its closest relative may be '' Scolomys''. It ranges from Central America east to the Guianas The Guianas, also spelled Guyanas or Guayanas, are a geog ...

'' in 1913, as ''Zygodontomys obtusirostris'', but admitted that it was atypical for its long tail. In 1944,

Philip Hershkovitz Philip Hershkovitz (12 October 1909 – 15 February 1997) was an American mammalogy, mammalogist. Born in Pittsburgh, he attended the Universities of Pittsburgh and Michigan and lived in South America collecting mammals. In 1947, he was appointed ...

published a revision of the genus ''

Nectomys ''Nectomys'' is a genus of rodent in the tribe Oryzomyini of family Cricetidae. Musser and Carleton, 2005. It is closely related to '' Amphinectomys'' and was formerly considered congeneric with '' Sigmodontomys''. It consists of five species, wh ...

'' as then understood, and in comparing it to what is now '' Sigmodontomys alfari'', he listed, in a footnote, the names he understood as

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

s of ''Oryzomys albigularis''.Hershkovitz, 1944, p. 72, footnote 16 This list included both ''keaysi'' and ''obtusirostris'', and since then the two have remained associated with each other and with ''O. albigularis'', initially as synonyms or subspecies. By the 1990s, however, the distinctiveness of ''O. keaysi'' with respect to both ''O. albigularis'' and '' O. levipes'' was recognized, and as a result ''O. keaysi'' was again classified as a separate species, now with ''O. obtusirostris'' as a synonym. When ''O. albigularis'' and related species were transferred to the new genus ''Nephelomys'' in 2006, this arrangement remained in place, but with the species now known as ''Nephelomys keaysi''.

References

Literature cited

*Allen, J.A. 1900. On mammals collected in southeastern Peru by Mr. H. H. Keays, with descriptions of new species. Bulletin of the American Museum of Natural History 13:219–228. *Allen, J.A. 1913. New South American Muridae. Bulletin of the American Museum of Natural History 32:597–604. *Hershkovitz, P. 1944. A systematic review of the Neotropical water rats of the genus ''Nectomys'' (Cricetinae). Miscellaneous Publications Museum of Zoology, University of Michigan 58: 1–88. *Musser, G.G. and Carleton, M.D. 2005. Superfamily Muroidea. Pp. 894–1531 in Wilson, D.E. and Reeder, D.M. (eds.). Mammal Species of the World: a taxonomic and geographic reference. 3rd ed. Baltimore: The Johns Hopkins University Press, 2 vols., 2142 pp. *Thomas, O. 1901. New mammals from Peru and Bolivia, with a list of those collected from the Inambari River, Upper Madre de Dios. Annals and Magazine of Natural History (7)7:178–190. * * {{Taxonbar, from=Q1762205 Mammals of Bolivia Mammals of Peru Nephelomys Mammals described in 1900 Taxa named by Joel Asaph Allen Taxonomy articles created by Polbot