Keays's Rice Rat
Encyclopedia
Nephelomys keaysi, also known as Keays's Oryzomys or Keays's Rice Rat, is a species of rodent
in the genus Nephelomys
of family Cricetidae
. It is found from southeastern Peru
to northern Bolivia
on the eastern slope of the Andes
in Yungas
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
", destruction of its habitat may pose a threat to some populations.
In 1900, Joel Asaph Allen
described two rodents from Juliaca
, Peru, at an altitude of 6000 feet (1,828.8 m) 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
, 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
in 1913, as Zygodontomys obtusirostris, but admitted that it was atypical for its long tail. In 1944, Philip Hershkovitz
published a revision of the genus Nectomys
as then understood, and in comparing it to what is now Sigmodontomys alfari, he listed, in a footnote, the names he understood as synonym
s of Oryzomys albigularis. 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.
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 genus Nephelomys
Nephelomys
Nephelomys is a genus of South American oryzomyine rodents found in the Andes from Bolivia to Venezuela, with a westward extension into the mountains of Costa Rica...
of 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 found from southeastern 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....
to northern Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
on the eastern slope of 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...
in Yungas
Yungas
The Yungas is a stretch of forest along the eastern slope of the Andes Mountains from southeastern Peru through central Bolivia. It is a transitional zone between the Andean highlands and the eastern forests. Like the surrounding areas, it has characteristics of the Neotropic ecozone...
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
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
", destruction of its habitat may pose a threat to some populations.
In 1900, Joel Asaph Allen
Joel Asaph Allen
Joel Asaph Allen was an American zoologist and ornithologist, born in Springfield, Massachusetts.He studied at Harvard University under Louis Agassiz...
described two rodents from Juliaca
Juliaca
Juliaca is San Roman's capital city in Puno Region, which is situated in southeastern Peru. It is the region's largest city with a population of 225,146 inhabitants , on the Altiplano, Juliaca above sea level, is located in the Collao Plateau and it is northwest of Lake Titicaca...
, Peru, at an altitude of 6000 feet (1,828.8 m) 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
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...
, 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
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. It contains two species: Zygodontomys brunneus and Zygodontomys brevicauda....
in 1913, as Zygodontomys obtusirostris, but admitted that it was atypical for its long tail. In 1944, Philip Hershkovitz
Philip Hershkovitz
Philip Hershkovitz was an American mammalogist. Born in Pittsburgh, he attended the Universities of Pittsburgh and Michigan and lived in South America collecting mammals. In 1947, he was appointed a curator at the Field Museum of Natural History in Chicago and he continued to work there until his...
published a revision of the genus Nectomys
Nectomys
Nectomys is a genus of rodent in the tribe Oryzomyini of family Cricetidae. It is closely related to Amphinectomys and was formerly considered congeneric with Sigmodontomys...
as then understood, and in comparing it to what is now Sigmodontomys alfari, he listed, in a footnote, the names he understood as synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
s of Oryzomys albigularis. 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.
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. ISBN 978-0-8018-8221-0
- 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.
- Weksler, M., A. R. Percequillo, and R.S. Voss. 2006. Ten new genera of oryzomyine rodents (Cricetidae: Sigmodontinae). American Museum Novitates 3537:1–29.
- Zeballos, H., Vargas, J. and Weksler, M. 2008. Nephelomys keaysi. In IUCN. 2008 IUCN Red List of Threatened Species. Retrieved on April 24, 2009.