439.

Mato Grosso Pygmy Rice Rat

Oligoryzomys mattogrossae

French: Colilargo du Mato Grosso / German: Mato-Grosso-Zwergreisratte / Spanish: Rata arrocera pigmea de Mato Grosso

Other common names: Mato Grosso Colilargo

Taxonomy. Oryzomys (Oligoryzomys) maittogrossae J. A. Allen, 1916, Utarity, Matto Grosso, Brazil.

Some populations of O. mattogrossae in Brazil have been referred to as O. fornesu. Monotypic.

Distribution. NE & SC Brazil and E Paraguay.

Descriptive notes. Head—body 90-95 mm, tail 115-130 mm, ear 13-2-14 mm, hindfoot 21-1-22-2 mm; weight 16-4-18-8 g.

The Mato Grosso Pygmy Rice Ratis a small-sized species of Oligoryzomys species. It has rufous-toned dorsum, especially on rump; underparts are light ocherous buff; dorsal and ventral colors are well-delineated; and upper one-half of ventral hairs is yellowish, with gray bases. Tail is longer than head-body length, sparsely haired, and covered with conspicuous epidermal scales;it lacks long tuft of terminal hairs and is weakly bicolored, dark gray above and light gray below.

Habitat. Open vegetation biomes such as Cerrado and Caatinga but also formations in transition with Amazonian forest. In a study in the Pantanal of Brazil, the Mato Grosso Pygmy Rice Rat was found in grasslands, savanna woodlands, and Bromelia-dominated forest edge but not in deciduous semideciduos forest.

Food and Feeding. The Mato Grosso Pygmy Rice Rat is granivorous, but it seasonality can prefer insect parts.

Breeding. Adult male Mato Grosso Pygmy Rice Rats were collected in March and August. Pregnant females were collected in March and September—October; numbers of embryos were 1-4.

Activity patterns. Mato Grosso Pygmy Rice Rats are terrestrial and crepuscular or nocturnal.

Movements, Home range and Social organization. Some competition for space and food was reported between the Mato Grosso Pygmy Rice Rat and the Terraced Rice Rat ( Cerradomys subflavus). In several studies, the Mato Grosso Pygmy Rice Rat was reported as one of the most abundant species of rodents, although it is difficult to separate it from other sympatric species of Oligoryzomys, such as the Utiariti Pygmy Rice Rat ( O. utiaritensis).

Status and Conservation. Not assessed on The IUCN Red Lust.

Bibliography. Allen (1916), Boroni et al. (2015), Carmignotto, Bezerra & Rodrigues (2014), Carmignotto, de Vivo & Langguth (2012), Emmons (2009), Hannibal & Caceres (2010), Lacher & Alho (2001), Lacher et al. (1990), Mares, Braun & Gettinger (1989), Mares, Ernest & Gettinger (1986), Olds & Anderson (1987), de la Sancha (2014), Weksler & Bonvicino (2015b), Weksler et al. (2017).