Elephantulus rupestris (A. Smith, 1831)

Russell A. Mittermeier & Don E. Wilson, 2018, Macroscelididae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 206-234 : 233

17.

Western Rock Sengi

Elephantulus rupestris

French: Sengi des rochers / German: Westliche Elefantenspitzmaus / Spanish: Sengi de roca occidental

Other common names: Western Rock Elephant-shrew, Smith's Rock Elephant-shrew, Smith's Rock Sengi

Taxonomy. Macroscelides rupestris A. Smith, 1831 ,

mountains near the mouth of the Orange River . Restricted by G. C. Shortridge in 1934 to Little Namaqualand, South Africa.

This species is monotypic.

Distribution. W & S Namibia and W South Africa (Northern Cape, Western Cape, and Eastern Cape provinces).

Descriptive notes. Head-body 116-133 mm, tail 124-162 mm, ear 25-31 mm, hindfoot 32-35 mm; weight 44-65 g. Female Western Rock Sengis can be slightly larger than males, but there is no substantial sexual dimorphism in bodysize. Overall, the Western Rock Sengi looks very much likeits sister species, the Bushveld Sengi ( E. intufi ). In the wild, these two species can be difficult to distinguish, particularly where they occur adjacent to one another in areas where scrublands abut rocky outcrops. Distinguishing characteristics include longer tail (Western Rock Sengi c.115% of head-body length vs. Bushveld Sengi ¢.105%), darker dorsal tail (Western Rock Sengi near-black vs. Bushveld Sengi speckled gray), and presence of terminal tail tuft (absent in Bushveld Sengi). Pinnae are broad and upright, and snoutis long, thin, and flexible. Dorsum is gray-brown or rufous-brown. Some hairs, particularly along mid-dorsal axis, are longer and have black tips. Pelage of dorsal head and face is similar in color to dorsal body. Lateral fur is gray, and venter is gray-white to off-white. Behind each ear, distinctive patch of rufous-buff-yellow hair extends onto nape of neck. Long pale hairs grow along anterior margin of each pinna. White eyering is present (but subtle), without intruding post-ocular patch. Hairs on top oftail

are nearly black but are paler below. Black hairs form tuft near tip of tail. Skin of plantar pesis black and hairless. Females have two anterior, two intermediate, and two posterior nipples; males have no nipples. Five digits are present on each manus and pes. Pectoral gland is absent, and subcaudal gland is present. Dental formula is 13/3,C1/1,P 4/4, M 2/2 (x2) = 40. Canine sizes are subequal to adjacent teeth. Several bilateral pairs of palatal foramina are present. Postorbital processes are absent. Karyotype is 2n = 26.

Habitat. Arid to semiarid rocky substrates including kopjes, outcrops, and boulder piles. Habitats of Western Rock Sengis have minimal vegetative cover but can be adjacent to relatively flat and sparsely vegetated compact sandy ground. Sheltering occurs among boulders and in rock crevices.

Food and Feeding. Insects, predominantly ants and termites, are the principal diet of the Western Rock Sengi. Other small invertebrates and small quantities of plant material are eaten.

Breeding. The Western Rock Sengi is probably monogamous. Females can produce severallitters per year, suggesting year-round mating, but in southern areas, reproduction can be seasonalas in the Bushveld Sengi. Embryo counts indicate that litters have 1-2 young. Direct paternal investment is absent from all species of sengis that have been studied. No species of soft-furred sengis use nests to shelter or for rearing their young.

Activity patterns. Western Rock Sengis are fully terrestrial and mainly crepuscular, with nocturnal tendencies. Midday activity is least frequent.

Movements, Home range and Social organization. Trapping efforts often yield male— female pairs of Western Rock Sengi, suggesting their home ranges overlap.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Western Rock Sengiis widespread, but its population trend is unknown.

Bibliography. Corbet & Hanks (1968), Evans (1942), Faurie (1996), Olbricht & Stanley (2009), Perrin (2013e), Rathbun (2009), Rathbun & Smit-Robinson (2015b), Rautenbach & Schlitter (1977), Shortridge (1934, 1942), Tolliver et al. (1989), Withers (1979).

Figures

1. Golden-rumped Seng (Rhynchocyon chrysopygus), 2. Chequered Sengi (Rhynchocyon cirne), 3. White-tailed Sengi (Rhynchocyon stuhlmanni), 4. Black-and-rufous Sengi (Rhynchocyon petersi), 5. Gray-faced Sengi (Rhynchocyon udzungwensis), 6. Namib Round-eared Sengi (Macroscelides flavicaudatus), 7. Karoo Round-eared Sengi (Macroscelides proboscideus), 8. Etendeka Round-eared Sengi (Macroscelides micus), 9. Four-toed Sengi (Petrodromus tetradactylus), 10. North African Sengi (Petrosaltator rozeti), 11. Rufous Sengi (Elephantulus rufescens), 12. Somali Sengi (Elephantulus revoulii), 13. Dusky-footed Sengi (Elephantulus fuscipes), 14. Short-snouted Sengi (Elephantulus brachyrhynchus), 15. Dusky Sengi (Elephantulus fuscus), 16. Bushveld Sengi (Elephantulus intufi), 17. Western Rock Sengi (Elephantulus rupestris), 18. Eastern Rock Sengi (Elephantulus mywrus), 19. Cape Rock Sengi (Elephantulus edwardii), 20. Karoo Rock Sengi (Elephantulus pilicaudus)

Distribution. W & S Namibia and W South Africa (Northern Cape, Western Cape, and Eastern Cape provinces).