''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 (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 ''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 over 870 species, it is either the largest or second-largest family ...

.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, is a generally tropical or subtropical, evergreen, Montane forest, montane, Tropical and subtropical moist broadleaf forests, moist forest characteri ...

in the Cordillera de la Costa Central of

Aragua Aragua State (, ) is one of the 23 states of Venezuela. It is located in the north-central region of Venezuela. It has plains, jungles and Caribbean beaches. The most popular beaches are Cata and Choroni. It has Venezuela's first national par ...

, Miranda, and the

Distrito Federal A federal district is a specific administrative division in one of various federations. These districts may be under the direct jurisdiction of a federation's national government, as in the case of federal territory (e.g., India, Malaysia), or th ...

in north-central

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

at elevations from 1000 to 2500 m. It is

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

and terrestrial, and has a varied diet. In most ''Nephelomys'' species, the posterolateral palatal pits, 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 sep ...

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

Ecuadorian Ecuadorians () 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 collectively the source o ...

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, London, Natural History Museum on mammals, describing about 2,000 new species and subspecies for ...

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 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 discerned by de ...

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 Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

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