''Nephelomys caracolus'', also known as the Costa Central oryzomysMusser and Carleton, 2005, p. 1146 or caracol rice rat, is a species of

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

in the genus ''

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. Its generic name is derived from the Ancient Greek word ''nephelê'' "mist", ...

'' 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 almost 608 species, it is the second-largest family of mammals, and has m ...

.Weksler et al., 2006, p. 18 It is found in

cloud forest A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest (TMCF), is a generally tropical or subtropical, evergreen, montane, moist forest characterized by a persistent, frequent or seasonal low-level cloud c ...

in the

Cordillera de la Costa Central The Cordillera de la Costa Central is a range of the Venezuelan Coastal Ranges System (''Cordillera de la Costa''), in northern Venezuela. Geography The mountain range runs east— west along the northern Caribbean Sea coast. It is also known a ...

Aragua Aragua State ( es, Estado Aragua, ) is one of the 23 States of Venezuela, states of Venezuela. It is located in the north-central region of Venezuela. It has plains and jungle (terrain), jungles and Caribbean beaches. The most popular are Cata a ...

, Miranda, and the

Distrito Federal A federal district is a type of administrative division of a federation, usually under the direct control of a federal government and organized sometimes with a single municipal body. Federal districts often include capital districts, and they e ...

in north-central

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

at elevations from 1000 to 2500 m. It is

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

and terrestrial, and has a varied diet. In most ''Nephelomys'' species, the

posterolateral palatal pits In anatomy, posterolateral palatal pits are gaps at the sides of the back of the bony palate, near the last molars.Weksler, 2006, p. 34 Posterolateral palatal pits are present, in various degrees of development, in several members of the roden ...

, perforations of the

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 sepa ...

near the third molar, are conspicuous and receded into a fossa, but in ''N. caracolus'' and the

Ecuadorian Ecuadorians ( es, ecuatorianos) are people identified with the South American country of Ecuador. This connection may be residential, legal, historical or cultural. For most Ecuadorians, several (or all) of these connections exist and are collect ...

species '' N. nimbosus'', the pits are much smaller.Wekser et al., 2006, p. 19

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

originally described the species, in 1914, as a member of ''

Oryzomys ''Oryzomys'' is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (''O. palustris'') of the United States and ...

'', ''Oryzomys caracolus''. From 1960 on, it was included in '' Oryzomys capito'', the current ''

Hylaeamys megacephalus ''Hylaeamys megacephalus'', also known as Azara's broad-headed oryzomys or the large-headed rice rat, is a species of rodent in the genus ''Hylaeamys'' of family Cricetidae, of which it is the type species. It is found mainly in lowland tropical ...

'', and subsequently in '' Oryzomys albigularis''. In the 1990s, studies of the Venezuelan populations of the ''O. albigularis'' group, based on data from

karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...

s and

morphometrics Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...

, provided evidence for the distinctiveness of ''O. caracolus'' and the other Venezuelan species of the group, '' O. meridensis''. The patterns recovered differ in details among the studies, however, and some authors chose to retain ''O. caracolus'' and ''O. meridensis'' as

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of ''O. albigularis'', suggesting a need for further study on the classification of Venezuelan members of the group. When the members of the ''O. albigularis'' group were transferred to the new genus ''Nephelomys'' in 2006, ''caracolus'' was retained as a species, ''Nephelomys caracolus''.

References

Literature cited

* * * {{Taxonbar, from=Q1766831 Mammals of Venezuela Nephelomys Mammals described in 1914 Taxa named by Oldfield Thomas