92.

Robert’s Snow Vole

Chionomys roberti

French: Campagnol de Robert / German: Robert-Schneemaus / Spanish: Topillo nival de Robert

Taxonomy. Microtus roberti Thomas, 1906, “Sumela, south of Trebizond [= Trabzon, Turkey]. Alt. 700-1300 m.”

Chionomys roberti is in the roberti species group. Two subspecies ( roberti and personatus) are consistent with phylogenetic structuring, but their geographical extents are not resolved. Subspecific taxonomy requires reassessments.

Distribution. E Pontic Mts in NE Turkey and Caucasus in SW European Russia, Georgia, and N Azerbaijan.

Descriptive notes. Head-body 125-156 mm, tail 80-108 mm; weight 40-78 g. Although Robert’s Snow Vole closely resembles other species of Chionomys in external appearance and craniodental morphology,itis substantially larger, has shorter and less soft fur, has relatively long tail (57-80% of head-body length), and has dark pelage. Dorsal side is dark brown, and belly is smoke gray, shaded drab. Tail is blackish brown above and gray below. Terminal pencils are 4-5 mm. Vibrissae are up to 45 mm and black.Juveniles are darker, with slate colored belly, gray hindfeet, and nearly uniformly dark tail. Females have eight nipples. Skull is shallow, with small bullae and short incisive foramina. Supraorbital ridges converge but remain c.l mm apart even in the oldest individuals. M” is complex, with 4-5 inner salient angles.

Habitat. Humid coniferous, deciduous, or mixed forests, with dense understory along mountain creeks from sea levelto elevations of ¢.3200 m, optimally 1000-1500 m.

Food and Feeding. Robert's Snow Vole prefers ferns and leaves of black elder ( Sambucus nigra, Adoxaceae). It feeds on the ground and in bushes and trees up to several meters high. Fresh food is stored under stones along river beds.

Breeding. Breeding season of Robert’s Snow Vole is in May-August at high elevations or to late October close to the sea. Numbers of embryos are 1-4/female (mean 2-5) in Turkey, but up to seven embryos are reported from the Caucasus.

Activity patterns. Robert's Snow Vole is primarily nocturnal and semi-arboreal. Nests are under roots or stones.

Movements, Home range and Social organization. Robert's Snow Vole climbs trees up to 3-4 m aboveground. It does not swim to cross rivers but jumps from stone to stone.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Overall distribution of Robert’s Snow Vole is ¢.80,000 km?.

Bibliography. Bannikova et al. (2013), Gromov & Erbajeva (1995), Krystufek (1999c), Krystufek & Vohralik (2005), Pecheniuk (1974), Shenbrot & Krasnov (2005).