419.

Guinean Grass Rat

Arvicanthis rufinus

French: Rat-roussard de Temminck / German: Rote Grasratte / Spanish: Rata de hierba de Guinea

Other common names: Guinean Arvicanthis, Rufous Grass Rat

Taxonomy. Mus rufinus Temminck, 1853,

Elmina, Ghana.

Arvicanthis rufinus was previously treated as a form of A. niloticus . It is best diagnosed on chromosomal complement, 2n = 62, FN = 76 (“ANI4” of V. T. Volobouev and others in 2002), which correspond to specimens from west of the Niger River from Nigeria to Guinea. A. Monadjem and colleagues in 2015 assigned specimens from Central African Republic having 2n = 62,

FN = 56-58 to this species (referred to as “ANI-2” by G. Dobigny and others in 2013), but the status of populations east of the Niger River remain uncertain. On mtDNA grounds, rufinus is closest (5:4%) to “ANI-2” from Central African Republic, but this association is not supported by morphometric data. Wider sampling is required to test whether the Central African population is a distinct species. Monotypic.

Distribution. Guinea E to Nigeria, with isolated records from N Cameroon and Central African Republic.

Descriptive notes. Head-body 115-177 mm, tail 127-146 mm, ear 16-24 mm, hindfoot 29-38 mm; weight 59-168 g. This is a medium-sized rat; along with Blick’s Grass Rat ( A. blicki) it is the largest species in the genus. Fur is dorsally buffy brown, flecked with black, tinged with pale to deep red on the back and flanks, and whitish to gray ventrally. Ears are small, rounded and reddish. Tail is relatively long (96% of headbody length), dark above and whitish or pale brown below. On forefoot, first digit is absent and fifth is highly reduced but still bears a claw; five digits on hindfoot. Females have three pairs of nipples.

Habitat. Guinean and southern Sudanian deciduous forest and woodland savannas,as well as clearings in adjacent evergreen forests.

Food and Feeding. Guinean Grass Rats are presumably herbivorous.

Breeding. Reproduction is presumably seasonal.

Activity patterns. The Guinean Grass Rat is diurnal and terrestrial.

Movements, Home range and Social organization. Guinean Grass Rats are presumably colonial.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Dobigny et al. (2013), Ducroz et al. (1998), Fadda & Corti (2001), Happold (2013a), Monadjem et al. (2015), Volobouev, Ducroz et al. (2002).