Here we report the first record of Drymoreomys albimaculatus Percequillo, Weksler & Costa, (Cricetidae, Sigmodontinae) in Rio de Janeiro state, Brazil. The recently described taxon Drymoreomys albimaculatus is endemic to the Brazilian Atlantic Forest and its biology and genetics are still poorly known. Herein. PDF | Drymoreomys albimaculatus is a recently-described rodent and an Atlantic Forest endemic. It is rare and has a poorly defined geographic.

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Drymoreomys is a rodent genus in the tribe Oryzomyini that lives in the Atlantic Forest of Brazil.

Drymoreomys albimaculatus – Wikipédia, a enciclopédia livre

The single species, D. It lives in the humid forest on the eastern slopes of the Serra do Mar and perhaps reproduces year-round. Although its range is relatively large and includes some protected areasit is patchy and threatened, and the discoverers recommend that the animal be considered ” Near Threatened ” on the IUCN Red List.

Within Oryzomyini, Drymoreomys appears to be most closely related to Eremoryzomys from the Andes of Peru, a biogeographically unusual relationship, in that the two populations are widely separated and each is adapted to an arid or a moist environment. The pads on the hindfeet are very well developed and there is brown fur on the upper sides of the feet. The tail is brown above and below. The front part of the skull is relatively long and the ridges on the braincase are weak.

The palate is short, with its back margin between the third molars. Several traits of the genitals are not seen in any other oryzomyine rodent. The name refers to the animal’s occurrence in mountain forest. According to a phylogenetic analysis of evidence from morphologythe nuclear gene Ddrymoreomysand the mitochondrial gene cytochrome bDrymoreomys albimaculatus is most closely related to Eremoryzomys poliusan oryzomyine from northern Peru and the only species in the genus Eremoryzomys.

It is one of several tribes recognized within the subfamily Sigmodontinaewhich encompasses hundreds of species found across South America and into southern North America. Sigmodontinae is the largest subfamily of the family Cricetidaeother members of which include voleslemmingsalbimaculaatusand deermiceall mainly from Eurasia and North America. Drymoreomys albimaculatus is a medium-sized, long-tailed, short-eared, short-footed rodent.

Overall, the abimaculatus of the upperparts is orange to reddish- buff. The sides are reddish brown.

On the underparts, the hairs are grayish at the base and white at the tip, except on the throat, chest, and in some specimens groin, where the hairs are entirely white [12] drymoreomye trait unique among the oryzomyines. The small, rounded ears are covered with dense golden hairs on the outer and with reddish brown hairs on the inner surface.


The mystacial vibrissae whiskers on the upper lip are long, usually extending a little beyond the ears when laid back against the head, but the superciliary vibrissae whiskers above the eyes are short and do not extend beyond the ears. The upper surface on the forefeet is covered with brown fur, and there is white or silvery fur on the digits. Ungual tufts fur around the bases of the claws are present on the second through fourth digits.

On the sole, the pads dfymoreomys very large. In the skull, the rostrum front part is relatively long. The nasal and premaxillary bones extend in front of the incisorsforming a rostral tubewhich is shared among oryzomyines only with Handleyomys. The zygomatic notch a notch formed allbimaculatus a projection at the front of the zygomatic platea bony plate at the side of the skull is shallow. The interorbital region between the eyes drmyoreomys narrow and long, with the narrowest part towards the front.

The crests on the braincase and interorbital region are weakly developed. The incisive foramina openings in the front part of the palate are long, sometimes extending to between the first molars M1.

The bony palate is broad and short, albjmaculatus the posterior margin between the third molars M3. The mandible lower jaw is long and low. The coronoid processthe frontmost of the three main processes projections at the back of the jawbone, is large and about drymoromys high as the condyloid process behind it.

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The angular processbelow the condyloid, is fairly short and does not extend further backwards than the condyloid. The upper incisors are opisthodont with the cutting surface oriented backwards and have orange to yellow enamel. The upper molar rows are either almost parallel or slightly convergent with each other toward the front.

The molars are high-cusped, almost hypsodont. On M1, the anterocone the front cusp is divided into two cuspules on the lingual inner, towards the tongue and labial outer, towards the lips sides of the teeth.

The mesolopha crest near the middle of the labial side of the tooth, is long and well developed on each of the three upper molars.

On the lower molars m1 to m3allbimaculatus cusps on the labial side are located slightly in front of their lingual counterparts. The anteroconidthe front cusp on the m1, is divided in two. The m1, m2, and usually m3 have a mesolophida crest corresponding to the mesoloph but located on the lingual side.

There are 12 ribs and 19 thoracolumbar chest and abdomenfour sacraland 36 to 38 caudal tail vertebrae. There are three digits at the tip of the penis, of which the central one is the largest. The two lateral digits are not supported by mounds of the baculum penis bone. There is only one spine on the papilla nipple-like projection on the upper side of the penis. On the urethral process albimaculatux, located in the crater at the end of the penis, a fleshy process at the side, the lateral lobuleis present.


The preputial glands glands in front of the genitals are large. The lack of lateral bacular mounds, presence of a lateral drymkreomys, and size of the preputial glands are all unique traits among the oryzomyines. Both sex chromosomes are albimaculatud with one arm noticeably longer than the otherand X albimaculatis larger than Y. Blocks of heterochromatin albimacculatus present on all autosomes and the long arm of Y. Telomeric sequences are found near the centromeres of the sex chromosomes.

However, no other oryzomyine has exactly the same karyotype as D. This suggests an evolutionary trend of decreasing chromosome number within the clade. While there are some similar cases of relationships between Andean and Atlantic Forest animals, these involve inhabitants of humid forests in the Andes; Eremoryzomysby contrast, lives in an arid area.

Drymoreomys albimaculatus appears to be a specialist of dense, moist, montane and premontane forest. It has been found in disturbed and secondary forests as well as in pristine forest, but probably needs contiguous forest drynoreomys survive. Reproductive activity has been observed in females in June, November, and December and in males in December, suggesting that the species breeds year-round.

The range of Drymoreomys albimaculatus is relatively large and the species occurs in several protected areasbut it has only been drymoeeomys in seven localities and its habitat is threatened by deforestation and fragmentation. From Wikipedia, the free encyclopedia.

Drymoreomys – Wikipedia

A rodent genus with one species in the family Cricetidae from the Atlantic Forest of Brazil. Species of tribe Oryzomyini rice rats. Retrieved from ” https: Oryzomyini Mammals of Brazil Mammals described in Monotypic rodent genera. Articles with short description Articles with ‘species’ microformats Featured articles.

Views Read Edit View history. In other projects Wikimedia Commons Wikispecies. This page was last edited on 2 Octoberat By using this site, you agree to the Terms of Use and Privacy Policy. Drymoreomys Percequillo, Weksler, and Costa, Drymoreomys albimaculatus Percequillo, Weksler, and Costa, Collection localities of Drymoreomys albimaculatus.