''Scolomys ucayalensis'', also known as the long-nosed scolomysMusser and Carleton, 2005 or Ucayali spiny mouse is a

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 ...

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 ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. It is part of the genus ''

Scolomys ''Scolomys'' is a genus of rodent in the tribe Oryzomyini of the family Cricetidae. Some evidence suggests that it is related to ''Zygodontomys''. It is characterized, among other traits, by spiny fur. It contains two species, '' S. melanops'' an ...

'' within the tribe

Oryzomyini Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern United States to the southernmost parts of S ...

. It is found in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...

and

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

in various different habitats in the

Amazon rainforest The Amazon rainforest, Amazon jungle or ; es, Selva amazónica, , or usually ; french: Forêt amazonienne; nl, Amazoneregenwoud. In English, the names are sometimes capitalized further, as Amazon Rainforest, Amazon Forest, or Amazon Jungle. ...

Description

''Scolomys ucayalensis'' has a head-and-body length of between and a tail around 83% of this. The head is small but broad with a pointed snout and small rounded ears. The fur is a mixture of fine hairs and thicker, flattened spines. The dorsal surface is some shade of reddish-brown to reddish-black, sometimes grizzled or streaked with black, and the underparts are grey. The tail is nearly naked, and the hind feet are small but broad. The

hypothenar The hypothenar muscles are a group of three muscles of the palm that control the motion of the little finger. The three muscles are: * Abductor digiti minimi * Flexor digiti minimi brevis * Opponens digiti minimi Structure The muscles of hypot ...

pad (next to the outer digit on the sole of the foot) is either absent or reduced in size on the hind feet, and this contrasts with the otherwise similar '' Scolomys melanops '' which has well-developed hypothenar pads. The

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 ...

of ''S. ucayalensis'' has 2n = 50 and FN = 68, while that of ''S. melanops'' has 2n = 60, FN = 78.

Distribution and habitat

''S. ucayalensis'' is found on the eastern side of the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

in South America. Its range extends from southern Colombia and southern Ecuador, through western Brazil to northern Peru, and completely surrounds the range of ''S. melanops''. Its habitat varies, with specimens being found in primary terra firme (non-flooded) lowland humid forest in Brazil, in undergrowth growing where primary forest had been cut back, and in cloud forest where the trees are clad in

moss Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta (''sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hor ...

es and

bromeliads The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...

. Its altitudinal range is between .

References

Literature cited

* * {{Taxonbar, from=Q1768827 Scolomys Mammals described in 1991