553.

Serra do Mar Grass Mouse

Castoria angustidens

French: Akodon de la Serra do Mar / German: Serra-do-Mar-Grasmaus / Spanish: Raton campestre de la Sierra del Mar

Other common names: Cerrado Grass Mouse, Serra do Mar Akodont

Taxonomy. Habrothrix angustidens Winge, 1887, Lagoa Santa cave deposits, Minas Gerais, Brazil.

Castoria angustidens is the type species of the genus. Alpha-taxonomy of Castora needs a detailed approach; at least two additional names, serrensis named by O. Thomas in 1902 and leucogula by A. Miranda-Ribeiro, 1905 are available for binomial or trinomial classification. Monotypic.

Distribution. SE & S Brazil (from Espirito Santo to Rio Grande do Sul states) and NE Argentina (Misiones Province).

Descriptive notes. Head-body 84-119 mm, tail 70-101 mm, ear 11-23 mm, hindfoot 22-28 mm; weight 15-60 g. Malesare slightly larger and heavier than females. The Serra do Mar Grass Mouse is small to medium-sized, characterized by darker general color above and below, short mystacial vibrissae, short claws, and moderately long tail although shorter than head-body length. Dorsal and ventral colors are subtly delimited with weak countershading. Skins exhibit thick, soft fur (guard hairs ¢.9-12 mm). Dorsal furis dark yellowish brown to orangish brown; venter is washed with bright buff or tawny over darkgray hair bases. Eyes are small. Mystacial vibrissae do not extend posteriorly much beyond bases of pinnae; genal vibrissae are present. Ears are medium-sized, rounded, and internally and externally covered by brown hair. Tail is dark brown, unicolored, sparsely haired, and covered by sets of three somewhat hispid hairs per scale, with each dorsal hair covering 2-3 scale-rows; apical tuft is absent. Manus and pes are covered by short hair, with their basal portion brown and apical portion whitish. Claws, basally open on pes, are inconspicuous and dorsally covered by several whitish or darker ungual hairs, slightly surpassing their apices. Plantar surface is naked, pigmented, and slightly squamated. Chromosomal complement is 2n = 46, FN = 46.

Habitat. Much restricted to narrow coastal fringe in well-conserved forest remnants at elevations of 300-2100 m. Most recorded localities are located within Serra do Mar coastal forests and Araucaria Moist forests ecoregions. The Serra do Mar Grass Mouse has also been recorded from the Bahia Coastal and Interior Forests and at ecotones with the Alto Parana Atlantic Forests. Preferred vegetation is humid mountain forest, including those with Araucaria augustifolia ( Araucariaceae). The Serra do Mar Grass Mouse was the most frequently trapped small mammal in Desengano State Park, Rio de Janeiro, a disturbed montane forest at ¢.1000-1425 m and also was the dominant species among recorded sigmodontines in an elevational transect of Serra do Brigadeiro State Park from 1200 m to 1800 m, particularly at middle to upper elevations (1450-1800 m).

Food and Feeding. The Serra do Mar Grass Mouse is reported tenuously as insectivore/omnivore. Captive individuals fed mainly on pulp of fruits and also on small to medium-sized seeds of a wide array of plant species from the Atlantic Forest.

Breeding. No information.

Activity patterns. The Serra do Mar Grass Mouse is nocturnal. Analysis of the appendicular skeleton suggests that it uses terrestrial locomotion; individuals are captured mostly on the ground. It inhabits shallow tunnels under matted roots and moss and piles oflitter in thickets of mountain bamboos Chusquea (Poaceae) .

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as Akodon serrensis).

Bibliography. Abreu et al. (2014), Barros (2017), Bonvicino (2011), Bonvicino et al. (2002), Christoff et al. (2000), Coutinho et al. (2013), Geise (1995), Geise, Canavez & Seuanez (1998), Geise, Pereira et al. (2004), Hass et al. (2008), Kosloski (1997), Liascovich & Reig (1989), Miranda-Ribeiro (1905), Modesto et al. (2008), Moreira et al. (2009), Pardinas, D'Elia, Patterson & Teta (2016a), Pardinas, Geise et al. (2016), Pardinas, Teta, Alvarado-Serrano et al. (2015), Rodarte & Lessa (2010), Silveira et al. (2013), Teixeira et al. (2014), Testoni et al. (2012), Thomas (1902a), Ventura et al. (2009), Vieira & Monteiro-Filho (2003), Vieira et al. (2003), Winge (1887).