Micoureus demerarae (Thomas)

Rocha, Rita G., Ferreira, Eduardo, Costa, Barbara M. A., Martins, Iracy C. M., Leite, Yuri L. R., Costa, Leonora P. & Fonseca, Carlos, 2011, Small mammals of the mid-Araguaia River in central Brazil, with the description of a new species of climbing rat, Zootaxa 2789, pp. 1-34 : 13

Micoureus demerarae (Thomas)

Identification. A recent revision treats Micoureus as a subgenus of Marmosa in order to keep Marmosa a monophyletic genus ( Voss & Jansa 2009). Herein we follow the previous taxonomy of Wilson and Reeder (2005) and treat Micoureus as a full genus, once that its monophyly is well supported ( Voss & Jansa 2009), and combined with diagnostic characters, warrants recognition at the taxonomic level of genus and not subgenus.

This medium-bodied murine opossum has small eye masks that do not reach the nose, orange cheeks and the forehead is lighter than the rest of the body. Dorsal pelage is gray-brown and ventral pelage ranges from yellow to orange. The throat and inguinal regions have self-colored hairs, and the belly has self-colored hairs restricted to a midline and flanked with gray-based lateral hair. Its long and woolly fur and distinctly furred tail base (average 30 mm of tail length from the base) allow the diagnosis between the juveniles of this species and adult Marmosa murina . All but one M. demerarae had mottled tails (white spots or with the tip completely white), and the specimen UFES 1282 had a completely dark tail. This variation was also reported for the same species at Paracou ( Voss et al. 2001). Females have no pouch.

Measurements (n = 22): HB = 110–190, T = 205–245, HF = 22–30, E = 19–34, W = 71–140.

Distribution. This species occurs in Venezuela, Peru, Bolivia, Colombia, Guianas and northern and central Brazil, throughout humid forests of Amazonia and the northern part of the Atlantic Forest and the drier biomes of Cerrado and Caatinga ( Gardner 2007).

Natural history. Twenty-two individuals of M. demerarae , eleven of each sex, were captured on the ground (n = 18) and in the understory (n = 4) of flooded and upland forest. Six reproductively active females were captured from June to November 2007, three lactating and one with six pouch young and two with eleven pouch young.

Vouchers (n = 5: 2ɗ 3Ψ): UFES 1282–1285.