Jaculus orientalis Erxleben 1777
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
Jaculus
Jaculus orientalis

description: 31.
Greater Egyptian Jerboa
Jaculus orientalis
French: Gerboise d'Erxleben / German: Grote Wiistenspringmaus / Spanish: Jerbo grande de Egipto
Other common names: Oriental Jerboa
Taxonomy. Jaculus orientalis Erxleben, 1777,
“Aegypto, in monticulis Aegyptum ab Arabia diuidentibus [= Egypt, in the mountains separating Egypt from Arabia]”.
Morphologically and genetically, J. orienta lis is a member of the subgenus Haltomys, the sister group of the subgenus Jaculus. Molecular reconstructions retrieved two divergent allopatric lineages in North Africa: one in Morocco, Algeria, Tunisia, and western Libya and another in eastern Libya and Egypt. These two lineages diverged c.0-67 million years ago. Sinai Peninsula and Israel populations have not been studied genetically. Three subspecies recognized.
Subspecies and Distribution.
J.o.orientalisErxleben,1777—NEEgypt(SinaiPeninsula)andSIsrael(NNegev).
J.o.gerboaOlivier,1800—NELibyaandEgyptWofNileValley.
J. o. mauritanicus Duvernoy, 1841 — NE Morocco, N Algeria, Tunisia, and NW Libya.
Descriptive notes. Head-body 95-145 mm, tail 172-215 mm, ear 18-25 mm, hindfoot 55-70 mm; weight 104-182 g. Females are slightly larger than males. Head and dorsum of the Greater Egyptian Jerboa are brownish orange; sides and ventral pelage are pure white. Basal part of vibrissae is dark gray. Tail banner is wide and well flattened, with fuzzy white basal ring; black subterminal field and white terminal tuft are about equal in length; and ventral side of black subterminalfield has no white stripe along tail rod. Toes of hindfeet are covered from below with brushes of relatively long soft hairs; external hairs of brushes are white, with dark brown tips and internal black or dark brown; and toes do not have conic calluses at bases. Rostral part of skull is slender. Auditory bullae are strongly inflated and project from under braincase laterally and caudally. Mastoid cavity is large and partially subdivided into three sections by septs. In volume, mastoid cavity is about three times larger than tympanic cavity. Front surfaces of incisors are white. P! is absent. Molars are high-crowned, with terraced masticatory surfaces; crown heights of unworn molars are 140-150% of their lengths. Glans penis is massive, cylindrical, slightly elongated, and subdivided by deep longitudinal folds into two ventro-lateral lobes and one dorsal lobe; ventro-lateral lobes have shallow longitudinal depressions; dorsal lobe has pair ofstylet-shape, forward-directed thorns rooted in middle of lobe; anterior part of surface of dorsal lobe is covered by singlevertex, backward-directed aciculae increasing in size in backward direction; and posterior part of surface of dorsal lobe and all surfaces of ventro-lateral lobes are covered by flat, backward-directed comb-like scales. Os penis (baculum) is large (its length about equalto length of glans penis) and straight, with long horizontal proximalplate, large flat horizontal broadenings at distal end and vertical ridge. Chromosomal complement has 2n = 48 and FN = 92.
Habitat. Atlas steppe, clay and loess deserts, and salt marshes with Salicornia and other chenopod (Amaranthaceae) shrubs along Mediterranean coast, preferring areas with mosaic of patches of relatively dense shrubby vegetation and open spaces.
Food and Feeding. The Greater Egyptian Jerboa eats leaves, roots, and seeds. In the wild, it mainly eats leaves; in captivity, it can survive on only wheat and barley grains.
Breeding. Breeding of the Greater Egyptian Jerboa was recorded from end of March to August. Litters have 2-7 young (usually three).
Activity patterns. The Greater Egyptian Jerboa is strictly nocturnal. Some individuals become active at dusk, but most start their activity two hours after sunset. Hibernation is obligate and lasts from November to mid-March. Although some earlier research reported absence of hibernation, recent studies provided clear evidence of seasonal physiological changes typical of hibernation.
Movements, Home range and Social organization. When moving slowly, Greater Egyptian Jerboas use bipedal pacing, with alternating support by left and right hindfeet. At medium-speeds and when running fast, they use asynchronous ricochet jumps. Hops are 30-46 cm long; maximum speed is 3-2 m/s. Burrows are simple and usually have one tunnel with 2-3 right-angled turns. Tunnel starts at the ground’s surface with usually a plugged entrance and ends with nest chamber at depths of 40-80 cm (up to 200 cm); lengths of tunnels are 210-340 cm. In some cases, burrows have 1-2 additional tunnels ending with emergency exits. Wild Greater Egyptian Jerboas are mainly solitary, but they can be sociable and relatively frequently seen in groups of 2-3 individuals.
Status and Conservation. Classified as Least Concern on The IUCN Red List.
Bibliography. Ben Faleh, Granjon, Tatard, Ben Othmen et al. (2012), El Hilali & Veillat (1975), Hooper & El Hilali (1972), Kowalski & Rzebik-Kowalska (1991), Mendelssohn & Yom-Tov (1999), Osborn & Helmy (1980), Pisano et al. (2015), Ranck (1968), Schropfer et al. (1985), Shahin & Ata (2001), Shenbrot (2013).
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 98, DOI: 10.5281/zenodo.6591722