Cardiocranius paradoxus Satunin 1903
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
Cardiocranius
Cardiocranius paradoxus

description: 1.
Five-toed Pygmy Jerboa
Cardiocranius paradoxus
French: Gerboise a cinq doigts / German: Flinfzehen-Zwergspringmaus / Spanish: Jerbo pigmeo pentadactilo
Other common names: Five-toed Dwarf Jerboa, Satunin’s Jerboa
Taxonomy. Cardiocranius paradoxus Satunin, 1903,
Scharogol-Dzhin, Nan-Shan, NW Gansu, China.
This species is monotypic.
Distribution. E Kazakhstan (N of Lake Balkhash), NW & N China (N Xinjiang, N Gansu, Inner Mongolia [= Nei Mongol], Ningxia, and W Qinghai), NW & S Mongolia, and SE Russia (Ubsu-Nur Lake, S Tuva).
Descriptive notes. Head—body 52-68 mm, tail 68-91 mm, ear 7-10 mm, hindfoot 24-28 mm; weight 9-19 g. The Five-toed Pygmy Jerboa is very small, with no significant secondary sexual dimorphism. Condylo-basal lengths of skulls are 17-1-18-8 mm, mastoid breadths are 15-8-18-2 mm, and maxillary tooth row lengths are 3-4-4 mm. Head and dorsum are grayish, reddish brown, or clay-gray and less often ash-gray or brownish ocher; sides and ventral pelage are pure white. Tail is short and fatty, without banner. Hindfeet have five toes and conic calluses at bases of toes. Toes of hindfeet are covered from below with brushes of relatively short (4-5 mm length) soft hairs; external hairs of brushes are white; and internal hairs are gray or dark brown. Ears are short and tubiform. Auditory bullae are greatly inflated and strongly project from under braincase laterally and caudally. Mastoid cavity is large and completely subdivided into four sections by septum. In volume, mastoid cavity is about twice as large as the tympanic cavity. Front surfaces of incisors are orange-yellow. P' is present but c.2-5 times smaller in diameter than M?®. Molars are low-crowned, with tuberculous surfaces; crown heights of unworn molars are ¢.60% oftheir lengths. Glans penis 1s medium-sized, spindle-shaped, compressed dorso-ventrally, and subdivided by deep longitudinal ventral and dorsal folds into two lateral lobes; ventral side has pair of stylet-shape, forward-directed thorns rooted in middle of ventral fold; and surfaces of lobes are covered by small single-vertex, backward-directed aciculae not differentiated in size. Os penis (baculum) is small and rachis-like;its length about equal to one-fourth of length of glans penis. Chromosomal complement has 2n = 48 and FN = 96.
Habitat. Gravel plains of semi-deserts and deserts in lower parts of mountain foothills with perennial grasses of Stipa (Poaceae): S. sareptana and S. orientalis in central Kazakhstan and S. gobica and S. glareosa in Mongolia.
Food and Feeding. The Five-toed Pygmy Jerboa is granivorous and specializes mainly on seeds of species of Stipa.
Breeding. Pregnant Five-toed Pygmy Jerboas were recorded in eastern Kazakhstan in June and Mongolia in July-August. Females produce one litter per year. Litters have 1-5 young (average 3-5).
Activity patterns. The Five-toed Pygmy Jerboa is strongly nocturnal; activity lasts 4-6 hours. Hibernation starts in September and ends probably in April.
Movements, Home range and Social organization. Home ranges of Five-toed Pygmy Jerboas are 0-6-3 ha. Social interactions are mainly agonistic but distant, usually without direct fighting. Living summer burrows have up to four entrances and one nest chamber 8 cm in diameter at depths of 25-35 cm. Winter burrows have two entrances and 3-4 nest chambers at depths of 30-80 cm.
Status and Conservation. Classified as Data Deficient on The IUCN Red List. The Fivetoed Pygmy Jerboa is classified as data deficient on The Mongolian Red List of Mammals and vulnerable in The Red Data Book ofKazakhstan.
Bibliography. Shenbrot et al. (2008), Sokolov et al. (1996), Zhang Yongzu et al. (1997).
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 83, DOI: 10.5281/zenodo.6591722