Paradipus ctenodactylus
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
Paradipus
Paradipus ctenodactylus

description: 25.
Comb-toed Jerboa
Paradipus ctenodactylus
French: Gerboise a peignes / German: Kammzehen-Springmaus / Spanish: Jerbo de pies en peine
Taxonomy. Scirtopoda ctenodactyla Vinogradov, 1929,
Repetek, Turkmenistan.
This species is monotypic.
Distribution. Karakum and Kyzylkum deserts in Turkmenistan, Uzbekistan, and S Kazakhstan.
Descriptive notes. Head-body 140-165 mm, tail 180-225 mm, ear 32-40 mm, hindfoot 75-84 mm; weight 112-185 g. There is no significant secondary sexual dimorphism. Condylo-basal lengths of skulls are 32-36-3 mm, mastoid breadths are 21-1-23-7 mm, and maxillary tooth row lengths are 6-3-7-7 mm. Head and dorsum are sandy yellow; sides and ventral pelage are pure white; and tail banneris bicolored, wide and flattened, with ash-gray subterminal field (30-40 mm length) and long (35-45 mm length) white terminal tuft. Toes of hindfeet are covered from below with brushes of white relatively short (3 mm), firm, straight, and long (8-9 mm) soft hairs; toes do not have conic calluses at bases. Auditory bullae are inflated but project weakly from under braincase laterally and caudally. Mastoid cavity is large and completely subdivided into three sections. In volume, mastoid cavity is c.1-5 times smaller than tympanic cavity. Front surfaces of incisors are white. P' is absent. Molars are high-crowned, with flat masticatory surfaces; crown heights of unworn molars are ¢.225% of their lengths; molar crowns constantly grow up to 1-1-5 years of age, and roots start to develop only at this age. Glans penis is massive, conical, elongated, 9 mm long, 6 mm in diameter at base, and divided by deep longitudinal folds into two ventrolateral lobes and one dorsal lobe; lobes are subdivided by shallow longitudinal folds, three dorsally and ventro-laterally into two sections; dorsal lobe with pair of short clawshaped, forward-directed styles rooted at top of lobe; and surfaces of lobes are covered by backward-directed scales, two-apex at lateral surfaces and comb-like with 4-5 scallops on dorsal and ventral surfaces. Os penis (baculum) is long (its length about equal to length of glans penis), thin, and curved upward in central part, with small flat horizontal broadening at proximal end and narrow transversal bar at distal end. Chromosomal complement has 2n = 48 and FN = 94.
Habitat. Exclusively non-stabilized sands, with sparse shrubs (5-7% of canopy cover) represented by chenopods (Amaranthaceae), such as Haloxylon persicum or Salsola richteri, and Ammodendron sp. (Fabaceae).
Food and Feeding. The Comb-toed Jerboa is a specialized folivorous stenophage. Its diet contains mainly green leaves and stems of shrubs;it also eats insects in spring and seeds in late summer and autumn. Number of feeding plant speciesis low; local lists of foraging plants include 7-12 species of shrubs, annual and perennial grasses, and forbs. Comb-toed Jerboas obtain leaves and stems of succulent shrubs by cutting branches at heights of 30-150 cm by jumping and climbing into shrubs. They eat cut branches in the open 10-15 m from the nearest shrub.
Breeding. Breeding of the Comb-toed Jerboa occurs in April-July. Litters have 2-3 young (average range 2-4-2-8). One-year-old females produce one litter per year; 2-3-year-old females produce two litters. Sexual maturity occurs at 10-11 months after overwintering.
Activity patterns. The Comb-toed Jerboa is nocturnal. Aboveground activity usually starts 20-50 minutes after sunset and ends before sunrise. Hibernation lasts 2-3 months from the end of November/mid-December to mid-February/early March. Hibernation is related to seasonal absence of green plant food rather than cold weather.
Movements, Home range and Social organization. Comb-toed Jerboas move slowly when foraging, using bipedal pacing with alternating support by left and right hindfeet; lengths of steps are 16-24 cm. When running fast, they use asynchronous ricochet jumps. Maximum length of jump is 300 cm, and maximum speed is 8-8 m/s. Escape behavior is characterized by running fast along sand dune ridges, with frequent changes to the opposite dune slope. Total lengths of nightly movements are 3-5 km for females and 10-11 km for males in spring but only ¢.2-5 km in autumn. Home range are relatively narrow and extend along sand dune ridges;sizes are 3 ha at high densities to 20-30 ha for females and 50 ha for males at low densities. Home ranges overlap widely. Burrows are usually placed on slopes of moving sand dunes. Summer burrows of males and non-breeding females are simple and contain one tunnel (1:2-2-2 m long) ending in a chamber 13-14 cm in diameter and 25-65 cm deep without a nest; these burrows are used by an individual for 3-6 days, after which it excavates a new burrow. Burrows of breeding females have longer tunnels and soft plant litter in nest chambers; females use these burrows during late stages of pregnancy and lactation (c.50 days). Wintering burrows are used only during hibernation. These burrows are long (tunnel length up to 4-5 m) and deep (chambers at depths of 1-3 m).
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 pages 95-96, DOI: 10.5281/zenodo.6591722