Nephelomys nimbosus
Encyclopedia
Nephelomys nimbosus is a species of rodent
in the genus Nephelomys
of family Cricetidae
. Its type locality
is at San Antonio on the northeastern slope of the Tungurahua
in the Andes
of Ecuador
, at an altitude of about 6700 feet (2,042.2 m). The type series included five individuals.
The fur of the upperparts is brown to blackish, becoming lighter towards the sides. The underparts are grayish, with a white patch at the throat. The long tail virtually lacks hairs and is darker above than below. In the holotype
, the total length is 304 millimetres (11.97 in), the head and body length is 140 millimetres (5.51 in), the combined length of the tail vertebrae is 164 millimetres (6.46 in), the hindfoot length (including claws) is 34 millimetres (1.34 in), and the length of the skull is 35.5 millimetres (1.4 in). In most species of Nephelomys, the posterolateral palatal pits
, perforations of the palate
near the third molar, are conspicuous and receded into a depression or fossa
, but in N. nimbosus and N. caracolus, they are much smaller.
It was first described, in 1926, by American zoologist H. E. Anthony as a subspecies
of Oryzomys auriventer. It is smaller than that animal and differs in coloration and in the shape of the incisive foramina
, which resembles that seen in N. moerex
. In his description, Anthony anticipated that O. auriventer would eventually be demoted to a subspecies of Oryzomys albigularis, which was indeed done in the early 1960s. Subsequently, O. auriventer was reinstated as a species separate from, though related to, O. albigularis, and nimbosus was considered to belong to the same species. When the members of the Oryzomys albigularis group, including O. auriventer, were transferred to the new genus Nephelomys
in 2006, N. nimbosus was recognized as a separate species.
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...
. Its type locality
Type locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
is at San Antonio on the northeastern slope of the Tungurahua
Tungurahua
Tungurahua, , rahua : "Throat of Fire" or from Panzaleo) is an active stratovolcano located in the Cordillera Oriental of Ecuador. The volcano gives its name to the province of Tungurahua...
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 Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, at an altitude of about 6700 feet (2,042.2 m). The type series included five individuals.
The fur of the upperparts is brown to blackish, becoming lighter towards the sides. The underparts are grayish, with a white patch at the throat. The long tail virtually lacks hairs and is darker above than below. In 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...
, the total length is 304 millimetres (11.97 in), the head and body length is 140 millimetres (5.51 in), the combined length of the tail vertebrae is 164 millimetres (6.46 in), the hindfoot length (including claws) is 34 millimetres (1.34 in), and the length of the skull is 35.5 millimetres (1.4 in). In most species of Nephelomys, the posterolateral palatal pits
Posterolateral palatal pits
In anatomy, posterolateral palatal pits are gaps at the sides of the back of the bony palate, near the last molars. Posterolateral palatal pits are present, in various degrees of development, in several members of the rodent family Cricetidae...
, perforations of the palate
Palate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...
near the third molar, are conspicuous and receded into a depression or fossa
Fossa (anatomy)
In anatomical terminology, fossa has come to mean a depression or hollow, in general, in a bone. Other parts of the body may be involved, for example, the antecubital fossa...
, but in N. nimbosus and N. caracolus, they are much smaller.
It was first described, in 1926, by American zoologist H. E. Anthony as a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of Oryzomys auriventer. It is smaller than that animal and differs in coloration and in the shape of the incisive foramina
Incisive foramen
The fossa incisiva is an opening in the bone of the oral hard palate where blood vessels and nerves may pass. There are four of these openings in the incisive fossa.-Formation:...
, which resembles that seen in N. moerex
Nephelomys moerex
Nephelomys moerex is a species of rodent in the genus Nephelomys of family Cricetidae. The type locality is at Mindo in western Ecuador, where it has been recorded together with three other rodents of the oryzomyine group, Sigmodontomys aphrastus, Mindomys hammondi, and Handleyomys alfaroi, as well...
. In his description, Anthony anticipated that O. auriventer would eventually be demoted to a subspecies of Oryzomys albigularis, which was indeed done in the early 1960s. Subsequently, O. auriventer was reinstated as a species separate from, though related to, O. albigularis, and nimbosus was considered to belong to the same species. When the members of the Oryzomys albigularis group, including O. auriventer, were transferred to the new 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...
in 2006, N. nimbosus was recognized as a separate species.
Literature cited
- Anthony, H.E. 1926. Preliminary report on Ecuadorean mammals. No. 7. American Museum Novitates 240:1–6.
- 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
- Weksler, M., A. R. Percequillo, and R.S. Voss. 2006. Ten new genera of oryzomyine rodents (Cricetidae: Sigmodontinae). American Museum Novitates 3537:1–29.