Sicista napaea Hollister 1912
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 napaea

description: 8.
Altai Birch Mouse
Sicista napaea
French: Siciste de Altai / German: Nordliche Altai-Birkenmaus / Spanish: Raton listado de Altai
Taxonomy. Sicista napaea Hollister, 1912,
“ Tapucha [= Topuchaya], Altai Mountains, Siberia,” Russia.
Northern Species Group. In the opinion of B. S. Vinogradov in 1937, S. napaea was similar in color to members of the Eastern Montane Species Group but possessed many characters that separated it from other species in that group, such as tail length and structure and dimensions of hindfoot. Although karyotype of S. napaea is similar to S. strandi and S. pseudonapaea, unique morphology of glans penis of S. napaea supports its status as a valid species. Latest phylogenetic analysis using DNA sequences by T. Cserkész and colleagues in 2017 indicated that S. napaea is genetically close to S. betulina and S. strandi. D. 1. Bibikov and I. I. Stogov in 1963 caught three individuals in Chingiz-Tau Mountains, an area isolated from distribution of the nominal subspecies; they described a new subspecies, tschingistauca, based on those specimens. No other study has confirmed the status of this named form, and its phylogenetic legitimacy requires further study. Two subspecies recognized.
Subspecies and Distribution.
S.n.napaeaHollister,1912—NW&WAltaiMts(EKazakhstan),AltaiRepublic,andSWSiberia(Russia).
S. n. tschingistauca Bibikov & Stogov, 1963 — Chingiz-Tau Mts, Kazakh Uplands (E Kazakhstan).
Descriptive notes. Head-body 65-79 mm, tail 82-103 mm, ear 9-16 mm, hindfoot 16-20 mm; weight 9-19 g. The Altai Birch Mouse is one of the larger species of Sicista relative to body size. Dorsum is grayish brown with yellow hue or reddish brown;fur is sometimes more intensely colored compared with other species of unicolored Sicista. Dorsum of tschingistauca is brownish gray without red tones; body size is similar to that of nominal subspecies. Venteris grayish white, often with pale yellow or rusty tinge. Sides of body and cheeks appear paler and brighter due to absence of black-tipped guard hairs. Hindfoot is ¢.22-25% of head-body length. Tail is somewhat short, c.130% of head-body length. Tail is bicolored, brownish above, and whitish below, and in some individuals, it appears almost unicolored. Condylobasal lengths are 18-19-5 mm, zygomatic breadths are 9-8-10-4 mm, interorbital breadths are 3-8—4-2 mm, and lengths of upper tooth rows are 3-2-3-6 mm. Diploid number is 2n = 42. External and cranial measurements were obtained from adults captured from north-western and western Altai Mountains, published by G. I. Shenbrot and colleagues in 1995 and 2008. Penile morphology was described by Vinogradov in 1925; glans penisis cylindrical and covered with many small, and several large, lateral spines arranged in two rows. The two most prominent lateral spines can be seen with the naked eye and aids in identification of adult males and unambiguous distinction between adult male Altai Birch Mice and Gray Birch Mice (S. pseudonapaea).
Habitat. Wide variety of lowland and upland open habitats. N. G. Shubin and N. G. Suchkova in 1970 and 1971 captured 357 specimens of Altai Birch Mice on left banks of the Anuy and Charysh rivers in coastal shrubland (peashrub, Caragana, Fabaceae and meadowsweet, Filipendula, Rosaceae) and meadows and slopes of low mountains sparsely occupied by birch (Betula, Betulaceae). A. A. Sludskiy and colleagues in 1977 stated that they occur at elevations of 400-2220 m along riverbanks and in foothill steppes to alpine meadows covered with forb-grass vegetation and bushes. Additional specimens were captured above the forest zone (above 2200 m) in an alpine meadow near a colony of marmots. Altai Birch Mouse can be common in steep alpine meadows with freestanding cedars, spruce (Picea, Pinaceae)birch forests, and subalpine meadows with shrubs and rocky outcrops and in tall grasslands; they are rare in birch-larch (Larix, Pinaceae) forests, upland birch forests, and in short-grass habitats.
Food and Feeding. Diet of Altai Birch Mice consists of insects, seeds, and vegetative parts of plants. Shubin and Suchkova in 1975 reported that 23 stomach samples from the Soloneshnaya River Valley in July-August contained herb fragments (91:3% of total stomachs examined), seeds (82:6%), and insects (34-8%).
Breeding. Breeding period of Altai Birch Mice begins at the end of June, continues through July, and ends during the first half of August. Onelitter per year is produced, with 1-6 young/litter (four on average). Some individuals can reproduce twice in a year, as evidenced by a single female that was simultaneously lactating and pregnant.
Activity patterns. Altai Birch Mice are crepuscular and nocturnal. They are active c.4 months of the year and accumulate fat reserves in summer for use during hibernation, which lasts 7-5-8-5 months depending on climatic conditions. Shubin and Suchkova caught the first individuals on 18 May and the last one in early September. Altai Birch Mice are very sensitive to low temperatures. When an individual was captured in an alpine meadow on 22 July, it was torpid and immobile; researchers thought it had died from exposure to overnight low temperatures (2-3°C), but after being held in warm hands, the animal began to awaken and move about. Species of Sicista are known to enter this state in pitfall traps presumably to avoid damage from high or low temperatures and risk of desiccation, and they can quickly return to normal activity. It is likely that they aestivate during the active season, protecting themselves against extreme high or low ambient temperature fluctuations that are common in high mountains and semi-deserts.
Movements, Home range and Social organization. The Altai Birch Mouse is probably solitary. Density can be high in suitable habitats and reports of low abundance in ideal habitat may reflect difficulty of capturing them with conventional methods. B. S. Yudin and colleagues in 1979 reported the Altai Birch Mouse to be one of most abundant small mammals in the Tigireksky Nature Reserve on northern extensions of the Tigireksky Range in the north-western Altai highland.
Status and Conservation. Classified as Least Concern on The IUCN Red List. Populations ofAltai Birch Mice appearstable throughoutits distribution; however, its mountain habitats require protection. Several nature reserves have been established in the Altai Mountains, such as Katon-Karagay National Park in Kazakhstan and Tigireksky Nature Reserve and Golden Mountains of Altai UNESCO World Heritage Site in Russia.
Bibliography. Baskevich (2016), Bibikov & Stogov (1963), Cassola (2016a), Cserkész, Rusin et al. (2017), Gromov & Baranova (1981), Holden & Musser (2005), Kuznetsov (1965), Shenbrot et al. (1995, 2008), Shubin & Suchkova (1975), Sludskiy et al. (1977), Vinogradov (1925, 1937), Vozniychuk (2014), Yudin et al. (1979).
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 43, DOI: 10.5281/zenodo.6603557