Holochilus sciureus Wagner

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 : 14

Holochilus sciureus Wagner

Identification. Holochilus sciureus was the largest cricetid species captured in the study area. The dorsal pelage is long and soft, and brown streaked with black hairs. The dorsum is darker than the body sides, which become gradually lighter toward orange. The ventral pelage is a mix of white and orange fur. Younger individuals present darker dorsal pelages and completely white ventral pelages. Ears are rounded and hairy. The tail is slightly shorter than the body, bicolored and covered with thin hairs. Hind feet are webbed between the toes.

Craniodental characters ( Fig. 5 ) closely conform to published descriptions of this species (e.g., Voss & Carleton 1993; Patton et al. 2000; Barreto & García-Rangel 2005). The rostrum is broad and the zygomatic notches are deeply concave. The interobital region is hourglass shaped with distinct ridges extending over the temporal region. Incisive foramina are oval shaped and long, nearly extending to the anterior margin of molar rows. The mesopterygoid fossa extends to the posterior margin of molar rows. The alisphenoid strut is present and it has pattern 3 of carotid circulation (sensu Voss 1988) in which the spatedial foramen is small and the squamosal-alisphenoid groove and sphenofrontal foramen are absent. M1 and M2 have expanded paracones and no mesolophs. The same pattern is observed in the lower dentition, where m1 and m2 have no mesolophids.

Measurements (n = 2): HB = 136–170, T = 129–151, HF = 38–41, E = 21–25, W = 80–168.

Distribution. This species occurs in Venezuela, Guianas, Colombia, Ecuador, Bolivia, Peru and north and central Brazil throughout Amazonia and Cerrado biomes ( Musser & Carleton 2005).

Natural history. Four specimens of H. sciureus were captured in 30L pitfalls (n = 2) and Sherman traps (n = 2) placed close to the Javaés River at PEC, and near to an irrigation canal at FLV. One juvenile female was caught in August 2007, and two adults with scrotal testes and one juvenile male were trapped in October 2008.

Vouchers (n = 4: 3ɗ 1Ψ): UFES 1304–1307.

Figures

FIGURE 5. Dorsal, ventral and lateral views of skull and mandible of Holochilus sciureus (male, UFES 1306).