Sicista tianshanica
Creators: name: Don E. Wilson
name: Russell A. Mittermeier
name: Thomas E. Lacher, Jr
Publisher: name: Lynx Edicions
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Dipodidae
Sicista
Sicista tianshanica

description: 3.
Tian Shan Birch Mouse
Sicista tianshanica
French: Siciste du Tian Shan / German: Tienschan-Birkenmaus / Spanish: Raton listado de Tien Shan
Taxonomy. Sminthus tianshanica Salensky, 1903,
between Kapchagay (Chapzagaigol) and Tsaima (Zanma) rivers (= Kunges Basin, Gongnaisi River, tributary of Ili River, Xinyuan), S slope of Tian Shan Mts, Xinjiang, China.
Eastern Montane Species Group. Sicista tianshanica was described by W. Salensky, but he had no opportunity to compare material available to him with specimens of Sicista from other parts of Central Asia. J. R. Ellerman and T. C. S. Morrison-Scott in 1951 and A. V. Afanasyev in 1960 considered tianshanica a subspecies of S. concolor. Sicista tianshanica has a well-defined distribution, and no basis has been established for recognizing it as a population or subspecies of S. concolor (nominate population). V. E. Sokolov and Yu. M. Kovalskaya in 1990 described karyological and spermatozoal characteristics that supported recognition of S. tianshanica as a separate species, although they had no comparative material from S. concolor. According to T. Cserkész and colleagues, S. tianshanica forms the basal clade on the phylogenetic tree of Sicista, representing the earliest diverged lineage within the genus. Three chromosomal races have been identified with the following distributions: “Dzungarian” 2n = 34 form from Dzungarian Alatau, Tarbagatai Mountains, and Saur Mountains; “Terskei” 2n = 32 form from Inner and northern Tian Shan, Terskei Alatau, and Ketmen mountain ranges; and “Talgar” 2n = 32 form from the upper reaches of Talgar River (Trans-lli Alatau) and southern Dzungarian Alatau (Tyshkan River) near the Chinese border. The 2n = 34 “Dzungarian” form is currently being described by Cserkész and colleagues in 2017 as a separate, closely related species. They documentsignificant genetic divergence between the Talgar form (2n = 32, Trans-Ili Alatau) and the new species (Dzungarian form, 2n = 34 form, Dzungarian Alatau). It has not yet been determined if the distribution of the new species overlaps that of the Talgar form of S. tianshanica. Treated here as monotypic.
Distribution. E Tarbagatai Mts (including the Saur Mts) and Tian Shan (E from Chatkal River Valley), and possibly the Dzungarian Alatau in E Kazakhstan and NW China (W Xinjiang).
Descriptive notes. Head—body 57-73 mm, tail 102-113 mm, ear 12-5-15 mm, hindfoot 17-19 mm; weight 7-2-13 g. The Tian Shan Birch Mouse is the largest species of Sicista. Dorsum is grayish brown, venteris grayish yellow, and chin and throat are whitish. Throat and chest have white patches of variablesizes on ¢.81% of individuals; patches are less common on individuals from Terskei Alatau and Central Tian Shan and completely absent on individuals from Dzungarian Alatau, Tarbagatai, and Saur mountains. Sides of body and cheeks appear paler and brighter due to absence of black-tipped guard hairs. Hindfoot is long, ¢.25-27% of head-body length. Tail is long, ¢.147% (Terskei Alatau) to ¢.160% (Trans-Ili Alatau, and Tarbagatai Mountains) of head-body length. Tails are bicolored, darker above, and paler beneath. Condylobasal lengths are 18-3-20-6 mm, zygomatic breadths are 9-8-10-5 mm,interorbital breadths are 3-8—4-3 mm, and lengths of upper tooth rows are 3-2-3-5 mm. Diploid number is 2n = 32 with two distinctive karyotypic forms. External and cranial measurements of adult males were from Trans-Ili Alatau published by G. I. Shenbrot and colleagues in 1995 and 2008.
Habitat. Foothills to subalpine zone at elevations of 400-3500 m. Highest densities of Tian Shan Birch Mice were detected in upper limits of forests in subalpine zones, but they have been caught in a variety of habitats, such as edges of spruce (Picea, Pinaceae) forests, pastures, tall herb meadows, high mountain meadows, steppe-covered southern slopes, forest clearings, and subalpine meadows with junipers (Juniperus, Cupressaceae). Tian Shan Birch Mice also inhabit coniferous and broadleaf montane forests in alpine and subalpine zones, piedmont steppes, wet ravines, and slopes densely covered with tall herbs and shrubs, according to V. A. Bibikova in 1959, R. P. Zimina and M. A. Merkova in 1960, and P. Giraudoux and F. Raoul in 2015.
Food and Feeding. In Terskei Alatau (Kyrgyzstan), according to Zimina and Merkova in 1960, Tian Shan Birch Mice mostly eat insects and other animals such as snails, followed by seeds; fewer berries (strawberries, stone berry, currant, honeysuckle, rose hips) and herbs were found in stomachs. Proportion of insects and other animal food decreased from June to September, and quantities of seeds and berries increased. Proportions of herbsin diets remain about the same throughout summer (18-6-21%) and decrease in September (10-5%). Uneaten food is stored, along with debris (fir cones and chitinous parts of beetles and ants) that accumulates in the nest.
Breeding. Tian Shan Birch Mice breed once a year, producing litters of 3-7 young. Juveniles are sexually mature after their first winter. Reproduction begins in the first half of July, but elevation influences starting date and length of breeding seasons, being much shorter at higher elevations. In midlands of Trans-Ili Alatau, pregnant females were found in mid-June and late July. Young were first caught on 4 August, as noted by A. A. Sludskiy and colleagues in 1977. The oldest known Tian Shan Birch Mouse survived three winters, so highest life expectancy is c.4 years.
Activity patterns. Tian Shan Birch Mice are mainly crepuscular and nocturnal, although they are sometimes active during the day, particularly young individuals. Terrestrial and arboreal; they are agile climbers. Pitfall traps after a cold night—normal in the high mountains—regularly contained individuals lying curled on their side with closed eyes, seemingly in a state of torpor. They usually quickly became active when warmed in the hand. Tian Shan Birch Mice hibernate in winter, so their active period is only 3-5 months and is affected by elevation. In Issyk-Kul, mating began in the second half of May and early June, and last active individuals were last observed in the first half of October. In the Trans-Ili Alatau at elevations of ¢.2500 m, males were first trapped in late May and early June; females were first recorded in mid-June. At lower elevations, Tian Shan Birch Mice emerged at the beginning of May and latest capture was in early September. Adults probably enter hibernation in August because only juveniles have been captured in September. In the forest belt of Trans-Ili Alatau, males dominated catches in June due to their early awakening, and higher activity was detected in July, apparently correlated with breeding or increased mating activity. In August, number of captured adults decreased sharply, especially males.
Movements, Home range and Social organization. Zimina and Merkova in 1960 discovered Tian Shan Birch Mice shelters and nests in old decaying stumps and very rarely trunks of trees. Entrances are c.1:5-2 cm in diameter and usually 9-80 cm high on stumps. An 8-34 cm tunnel connected nest and entrance. Other tunnels in stumps either extended vertically and terminated in dead ends or connected with the nest. Nests were 6—12 cm wide and 3-8 cm high, filled with rotten wood, remains of food (termites, chitin of beetles, ants, cones of spruce, dandelion, and seed capsules of some herbaceous plants), pieces of moss and leaves, and rarely sheep wool. In montane forest belt, Tian Shan Birch Mice were found to occupy a cluster of stumps rather than isolated stumps, suggesting that they may form colonies under certain conditions. Stump holes and tunnels are not the only shelters used by Tian Shan Birch Mice. They are also common in alpine meadows or steppes of foothills that lack mature trees and decaying stumps, and in these habitats, they nest in grass nests or underground burrows. According to surveys in 1950-1960s reviewed by Sludskiy and colleagues in 1977, the Tian Shan Birch Mouse is common in suitable habitats, with high but fluctuating densities; such habitats are widespread in the Tian Shan Mountains. In 2017, Cserkész and colleagues reported densities of S. tianshanica sensu stricto captured in 2016 to be 17-3 ind/100 trap-nights in the Trans-Ili Alatau and the “new” species to be 5-5 ind/100 trap-nights in Dzungarian Alatau.
Status and Conservation. Classified as Least Concern on The IUCN Red List. Population trends of Tian Shan Birch Mice are unknown, but there is no reason to predict significant declines if habitats remain intact. The Tian Shan Birch Mouse might be the dominant species in local small mammal communities, and perhaps it is viewed as “hardly visible” and “rare” because there is scant information about its biology due to inadequate trapping methods and long hibernation periods.
Bibliography. Afanasyev (1960), Baskevich (2016), Bibikova (1959), Cassola (2016b), Cserkész, Flop et al. (2017), Ellerman (1961), Ellerman & Morrison-Scott (1951), Giraudoux & Raoul (2015), Gromov & Erbajeva (1995), Holden & Musser (2005), Kuznetsov (1948), Salensky (1903), Shenbrot et al. (1995, 2008), Sludskiy et al. (1977), Smith & Yan Xie (2013), Sokolov & Kovalskaya (1990a, 1990b), Vinogradov (1937), Zimina & Merkova (1960).
description: Published as part of Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Sminthidae, pp. 9-48 in Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona :Lynx Edicions on page 40, DOI: 10.5281/zenodo.6603557