Sicista kluchorica, Sokolov, Kovalskaya & Baskevich, 1980

Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Sminthidae, Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona: Lynx Edicions, pp. 9-48 : 41-42

5.

Kluchor Birch Mouse

Sicista kluchorica

French

: Siciste du Klukhor / German: KluchorBirkenmaus / Spanish: Raton listado de Kluchor

Taxonomy. Sicista kluchorica Sokolov, Kovalskaya & Baskevich, 1980 ,

at elevation of 2100 m, upper North Klukhor River at Klukhor Pass , Karachayevo-Cherkess Autonomous Region, northern Caucasus, Russia.

Western Montane Species Group. Sicista kluchorica is closely related to three other species that are endemic to the Greater Caucasus and Lesser Caucasus: S. caucasica , S. kazbegica , and S. armenica . According to G. I. Shenbrot and colleagues in 1995 and 2008, western limit of distribution of S. kluchorica is right bank of Kizgich River, a tributary of Bolshoi Zelenchuk River, and eastern limit verified by karyotype is in Baksan ravine, Azau River Valley, near Mount Elbrus. As Shenbrot and colleagues pointed out, S. kluchorica and S. caucasica are virtually indistinguishable based on external appearance and are extremely similar in cranial morphology. It is thus difficult to accurately outline distribution of S. kluchorica without karyological or molecular genetic data, especially in western part of its distribution. Monotypic.

Distribution. W Greater Caucasus in S Russia and NW Georgia.

Descriptive notes. Head-body 61-70-2 mm, tail 86-4-107-5 mm, ear 8:3-10-7 mm, hindfoot 15-9-21-6 mm; weight 5-:9-8-6 g. Dorsum of the Kluchor Birch Mouse is reddish/yellowish brown or yellowish gray, with conspicuous black guard hairs. Venter is grayish white. Sides of body and cheeks appear paler and brighter due to absence of black-tipped guard hairs. Hindfoot is long, ¢.30-35% of head-body length. Tail is very long, c.150-165% of head-body length, and bicolored, darker above and paler beneath. Condylobasal lengths are 17-2-17-9 mm, zygomatic breadths are 9-2 mm, interorbital breadths are 3-5-3-8 mm, and lengths of upper tooth rows are 2:8-3-4 mm. Surface of glans penis of all four species of Sicista endemic to the Caucasus is covered with small keratinized spines but lacks larger spines or penile spikes jutting out of terminus that characterize species in the Northern and Steppe species groups. Diploid number is 2n = 24. External and cranial measurements were taken from adult males captured from the Teberda River Basin, Russia, published by Shenbrot and colleagues.

Habitat. Subalpine meadows, forest glades, and riverbanks with tall grass or herbaceous understory at elevations of 1500-2600 m. Shenbrot and colleagues in 1995 and 2008 summarized habitats in which Kluchor Birch Mice have been captured and emphasized that all collecting localities were characterized by dense grass thickets. On right bank of Kizgich River at 1550 m, individuals were obtained in forest meadow predominantly covered with grass; parsnip ( Pastinaca ) and chervil ( Anthriscus ), both Apiaceae ; and nitrophilic herbs. In the Azau Valley near Elbrus at 2200 m, Kluchor Birch Mice were caught in a trampled meadow in birch ( Betula , Betulaceae ) elfin woodland, with dense cover that included alpine tall grass, and at 2300 m, they were captured in a boulder field with dense grass cover (c.95%) and isolated junipers ( Juniperus , Cupressaceae ). T. Cserkész and colleagues in 2017 captured individuals in the Mukhu River Valley at 2014-2330 m in areas with dense grass and herb cover and near Arkhyz at 1500 m in a marshy meadow surrounded by Scots pine ( Pinus sylvestris, Pinaceae ).

Food and Feeding. Little is known, but V. E. Sokolov and colleagues in 1981 reported that captive Kluchor Birch Mice ate invertebrates, fruit, and seeds.

Breeding. Breeding season of Kluchor Birch Mice begins in earlyJune; most litters are still nursing in late July to early August, although annual variation in temperature may shift breeding season by 2-3 weeks. In earlyJune, a fertilized female was captured that had four placental scars, probably from the previous year’s litter. Pregnant females with 5-7 embryos were captured in late July; average length of embryos of one female was 7-8 mm. Fifteen reproductively mature males were captured in late July in the Northern Klukhor River Valley at 2100 m, with average testes length of 4-6 mm and average testes width of 3-1 mm. In the same area, one female was caught in early August with four placental scars.

Activity patterns. Kluchor Birch Mice are probably predominantly crepuscular and nocturnal but sometimes active during the day. Length of hibernation has not been documented, but the closely related Caucasian Birch Mouse (S. caucasica ) hibernates 8-9-months of the year. There is no information about burrows and nests of the Kluchor Birch Mouse, but closely related species burrow under moss, under or inside of rotting logs and stumps, and emerge after snow recedes and warmer temperatures stabilize.

Movements, Home range and Social organization. Kluchor Birch Mice are solitary. Shenbrot and colleagues in 1995 and 2008 indicated that they were common in high mountain habitats such as Teberda River Basin and captured 18 ind/7 trap-nights. A. Bukhnikashvili and Shenbrot in 2008 stated that Kluchor Birch Mice are generally rare and characterized by low densities. Cserkész and colleagues in 2017 reported capture frequencies of 2-ind/100 trap-nights in intensively grazed subalpine meadow and 13 ind/100 trap-nights in mesophilous broadleaf grassland in Mukhu Valley above Teberda, Russia.

Status and Conservation. Classified as Near Threatened on The IUCN Red List. This classification is due to the limited distribution of the Kluchor Birch Mouse (less than 20,000 km?), relatively few collection sites, and seemingly low densities. Population trend was classified as unknown, but because the Kluchor Birch Mouse occurs in protected areas with no apparent major threats, its conservation status could potentially be changed to Least Concern. International collaborative action plans such as the Ecoregion Conservation Plan for the Caucasus published in 2012 have developed goals to conserve and protect habitats, fauna, and flora in the Caucasus due to its designation by Conservation International and other groups as a biodiversity hotspot based on high levels of diversity and endemism.

Bibliography. Baskevich (1996, 2016), Baskevich, Okulova et al. (2004), Baskevich, Potapov & Mironova (2016), Bukhnikashvili & Shenbrot (2008), Cserkész, Fllop et al. (2017), Shenbrot et al. (1995, 2008), Sokolov, Baskevich & Kovalskaya (1981, 1986a), Sokolov, Baskevich, Lukyanova et al. (1987), Sokolov, Kovalskaya & Baskevich (1980, 1987), Zazanashvili et al. (2012).

Figures

Distribution. W Greater Caucasus in S Russia and NW Georgia.