466.

Brazilian False Rice Rat

Pseudoryzomys simplex

French: Oryzomys de Winge / German: Trug-Reisratte / Spanish: Rata arrocera falsa de Brasil

Other common names: False Oryzomys

Taxonomy. Hesperomys simplex Winge, 1887, cave chamber (Lapa da Escrivania Nr. 5) near Lagoa Santa, Minas Gerais, Brazil.

Pseudoryzomys simplex is the type species of the genus. Although it is treated as monotypic, a subspecies, reigi, was named to distinguish Bolivian populations. Taking into account the large distribution, the possibility of a trinomial classification needs be examined deeply. Monoytpic.

Distribution. Brazil, extreme SE Peru (Pampas del Heath in Madre de Dios Region), Bolivia, Paraguay, and NE Argentina .

Descriptive notes. Head-body 99-127 mm, tail 102-133 mm, ear 18-21 mm, hindfoot 27-31 mm; weight 32:3-46 g. The Brazilian False Rice Rat is medium-sized, with coarsely grizzled brownish dorsum and gray-based yellowish or buffy venter. Pinnae are small, covered with short hair colored like fur on head, and do not appear naked. Hindfeet are long and narrow, with second, third, and fourth digits much longer than first and fifth digits; inconspicuous interdigital webbing is present between second, third, and fourth digits; heel is smooth and hairless, but rest of naked plantar surface is densely covered with small tubercles. Tail is distinctly bicolored (dark above and pale below), about as long as head-body length, and covered with short hairs, underlying epidermal scales are clearly visible; there is no terminal tail tuft of distinctly longer hair. There are four pairs of mammae in inguinal, abdominal, postaxial, and pectoral position. Chromosomal complement is 2n = 56, FN = 54.

Habitat. Tropical and subtropical grasslands and mostly flooding or wetland habitats below elevations of ¢.1000 m. The Brazilian False Rice Rat is largely confined to lowland unforested or savanna areas with strongly seasonal rainfall, such as grasslands and wetlands found throughout Chaco, Cerrado, and more rarely Caatinga domains.

Food and Feeding. The Brazilian False Rice Rat is supposedly herbivorous.

Breeding. No information.

Activity patterns. The Brazilian False Rice Rat is nocturnal. Individualss were captured on the ground in grassy habitats, usually seasonally flooded. A few morphological traits support close association between Brazilian False Rice Rats and freshwater bodies; however, no specimen has been trapped directly from water.

Movements, Home range and Social organization. The Brazilian False Rice Rat is hard to trap, surely because it avoids traditional baits, and most known specimens have been recovered from raptor pellets or caught in pitfall traps.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Nevertheless, the Brazilian False Rice Rat has suffered regional extinctions during the Holocene, particularly in southern areas such as Argentina and southern Brazil.

Bibliography. Anderson (1997), Bezerra et al. (2009), Bonvicino & Bezerra (2003), Carmignotto & Aires (2011), D’Elia, Mora et al. (2008), Hadler et al. (2016), Hershkovitz (1962), Lessa & Talamoni (2000), Machado et al. (2016), Massoia (1976), Pardinas (1995b), Pardinas, Cirignoli & Galliari (2004), Percequillo, Weksler, Pardinas & D’Elia (2016), Pine & Ranck (1969), Pine & Wetzel (1976), Thomas (1921b), Voss (2015d), Voss & Myers (1991), Wetzel & Lovett (1974), Winge (1887), Wolf et al. (2016).