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

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 ...

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 ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. 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, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

and

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

in various different habitats in the

Amazon rainforest The Amazon rainforest, also called the Amazon jungle or Amazonia, is a Tropical and subtropical moist broadleaf forests, moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin ...

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 hand, palm that control the motion of the little finger. The three muscles are: * Abductor minimi digiti muscle (hand), Abductor digiti minimi * Flexor digiti minimi brevis (hand), Flexor ...

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 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 ...

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 Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

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 plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

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