Oligoryzomys fornesi (Massoia)

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 : 20-21

Oligoryzomys fornesi (Massoia)

Identification. Craniodental characters of the mid-Araguaia specimens ( Fig. 11 ) closely agree with descriptions by Weksler and Bonvicino (2005) and Weksler (2006). The skull is small with tapered rostrum; zygomatic notches are deep and smoothly rounded; the interorbital region is hourglass shaped. The incisive foramen is long, terminating at the anterior of plan of M1; the mesopterygoid fossa is slightly arched or M-shaped and it is distant from M3. Sphenopalatine vacuities are large apertures along the presphenoid. It has the pattern 2 of carotid circulation (sensu Voss 1988) in which the stapedial foramen and posterior opening of alisphenoid canal are large, and the squamosalalisphenoid groove and sphenofrontal foramen are absent. The alisphenoid strut is absent. Upper incisors are opisthodont; the labial accessory root of M1 is absent; the hypoflexus of M3 is minute and disappears with wear.

Measurements (n = 9): HB = 67–82, T = 93–112, HF = 20–23, E = 15–17, W = 12–22.

Distribution. This species occurs in central Brazil ( Musser & Carleton 2005). This is the northwestermost record of O. fornesi , which expands the distribution of this Cerrado species to a transitional area with Amazonia.

Natural history. Eleven specimens (nine adults and two juveniles) were captured in pitfalls (n = 7) and Sherman traps (n = 4) placed in flooded forests at PEC and FSF, as well as in grasslands at FLV. In July and October 2008 two females were collected with four embryos each, and in November 2008 one female was collected with two embryos. Three adult males collected had scrotal testes.

Vouchers (n = 11: 4ɗ 7Ψ): UFES 1371–1379, 1440 –1441.

Figures

FIGURE 11. Dorsal, ventral and lateral views of skull and mandible of Oligoryzomys fornesi (female, UFES 1376).