Allactaga severtzovi Vinogradov 1925
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
Allactaga
Allactaga severtzovi

description: 10.
Severtzov’s Jerboa
Allactaga severtzouvi
French: Gerboise de Severtsov / German: Severtzov-Pferdespringer / Spanish: Jerbo de Severtzov
Taxonomy. Allactaga severtzovi Vinogradov, 1925,
Tamar-Utkul’, Taldy-Kurgan District, Kazakhstan.
Two subspecies are recognized.
Subspecies and Distribution.
A. s. severtzovi Vinogradov, 1925 — SE Kazakhstan (Almaty Region S of Lake Balkhash); it probably occurs in adjacent Xinjiang (NW China).
A. s. chorezmi Shenbrot, 1991 — S & SW Kazakhstan, Uzbekistan, N & NW Turkmenistan, and NW & SW Tajikistan.
Descriptive notes. Head—body 145-185 mm, tail 205-250 mm, ear 49-61 mm, hindfoot 67-81 mm; weight 122-220 g. There is no significant secondary sexual dimorphism. Condylo-basal lengths of skulls are 37-6-40-6 mm, zygomatic breadths are 26-29-4 mm, and maxillary tooth row lengths are 7-2-9-1 mm. Head and dorsum of Severtzov’s Jerboa are grayish clay; sides and ventral pelage are pure white; and tail banner is wide and well flattened, bicolored, with moderately long (35-55 mm) black subterminal field and long (40-60 mm) white terminal tuft; ventral side of black subterminal field is dissected along tail rod by wide white stripe with narrow black strip in the middle ofit. Toes of hindfeet are naked; conic calluses at bases of toes are large and high, with relatively narrow bases and rounded apexes. Auditory bullae are moderately inflated. Mastoid cavity is extremely small and not subdivided into sections; tympanic cavity is medium-sized. Front surfaces of incisors are white; incisors are moderately deflected forward. P' is relatively small, 1-6—1-7 times smaller in diameter than M?. Molars are medium-crowned, with terraced masticatory surfaces; crown heights of unworn molars are 90-115% of their lengths. Glans penis is egg-shaped, 6-:2—6-7 mm long and 4-4-5 mm wide,slightly compressed in dorso-ventral direction, subdivided by deep longitudinal dorsal fold into two lateral lobes; surfaces of lobes are covered by single-vertex, backwarddirected aciculae, increasing in size in backward direction; and aciculae are arranged in 4-5 concentric rows, with 9-10 aciculae in each row. Os penis (baculum) is absent. Chromosomal complement has 2n = 48 and FN = 96.
Habitat. Wide variety of desert habitats, avoiding only sands and rocky mountain slopes. Severtzov’s Jerboa inhabits plains with sagebrush (Artemisia, Asteraceae)—glasswort (Tecticornia, Amaranthaceae) vegetation on sandy gravel, sandy loam, loamy, and clay soils, preferring patches with abundant ephemeral plants.
Food and Feeding. Severtzov’s Jerboa is omnivorous. Seeds, insects, and green and underground plant parts are equally represented in the diet.
Breeding. Breeding of Severtzov’s Jerboa occurs in April-June, in some years into September. Litters have 1-7 young (average range 3-5—4-4). One-year-old and threeyear-old females produce one litter per year; two-year-old females usually produce two litters. Most individuals are sexually mature at 8-11 months old, after overwintering; in some rare cases, sexual maturity was observed at ¢.6 months of age when individuals born in spring bred in autumn of the same year. Gestation was estimated at 20-21 days. Young nurse for 40-50 days.
Activity patterns. Severtzov’s Jerboa is nocturnal. Aboveground activity usually starts 30-50 minutes after sunset in spring and autumn and 10-20 minutes after sunset in summer. Activity ends ¢.30 minutes before sunrise. Peak of activity occurs in the first one-half of the night in spring and autumn and at midnight in summer. Hibernation lasts from October/November to February.
Movements, Home range and Social organization. Severtzov’s Jerboas move slowly when they forage, using bipedal pacing with alternating support by left and right hindfeet; lengths of steps are 16-18 cm. When running fast, they use asynchronous ricochet jumps. Maximum length ofjump is 291 cm. Maximum speed when running is 10 m/s, but individuals can only run at this speed for 2-3 minutes. Escape behavior is characterized by a fast run for distances of 40-60 m before hiding in a shelter burrow. Home ranges at high density are 5-4 ha for males and 3-8 ha for females. At low density, home ranges are 7-12 ha. Home ranges of individuals of the same sex overlap marginally; home range of one adult male usually widely overlaps home ranges of 1-2 females. Summer burrows are simple and consist of the main tunnel, starting from the main entrance and ending after 2-3 right-angled turns at the bottom with nest chamber, and 1-2 additional tunnels starting from the main tunnel and leading to emergency exits. Main entrance is usually closed with soil plug. Emergency exits are dug up to 1.5-3 cm from the ground’s surface. Total lengths of tunnels are 1-6-5-3 m; nest chambers are 15-25 cm in diameter and 50-120 cm deep (usually 60-80 cm). Winter burrows differ from summer burrows by presence of additional nest chambers and greater depths (85-170 cm, usually 100-130 cm). Night shelter burrows are simple, with one tunnel 50-80 cm long and 60-70 cm deep. One individual can have 2-3 shelter burrows in its home range. Entrances of shelter burrows are obvious because of long (90-270 cm), well-used paths leading to them. In the wild, Severtzov’s Jerboas are solitary, and their interactions are relatively rare; among observed contacts, 88% were aggressive and the other, mutual avoidance. In captivity, intraspecific contacts are neutral, but interspecific contacts are extremely aggressive; Severtzov’s Jerboas often kill other jerboa species.
Status and Conservation. Classified as Least Concern on The IUCN Red List.
Bibliography. Shenbrot et al. (2008).
description: Published as part of Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Dipodidae, pp. 81-100 in Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona :Lynx Edicions on page 86, DOI: 10.5281/zenodo.6591722