Elephantulus mywrus, Thomas & Schwann, 1906

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 : 233-234

18.

Eastern Rock Sengi

Elephantulus mywrus

French: Sengi du Limpopo / German: Ostliche Elefantenspitzmaus / Spanish: Sengi de roca oriental

Other common names: Eastern Rock Elephant-shrew, Transvaal Elephant-shrew, Transvaal Sengi

Taxonomy. Elephantulus rupestris myurus Thomas & Schwann, 1906 , “ Woodbush , North-eastern Transvaal ,” Limpopo Province, South Africa .

This species is monotypic.

Distribution. Zimbabwe, W Mozambique, E Botswana, N, C & E South Africa, and N Swaziland; perhaps Lesotho.

Descriptive notes. Head-body 114-133 mm, tail 125-159 mm, ear 25-28 mm, hindfoot 37-42 mm; weight 48-67 g.

There is no evidence of sexual dimorphism in body size. Tail of the Eastern Rock Sengi is relatively long at ¢.110% of head-body length, pinnae are broad and upright, and snout is long, thin, and flexible. Dorsum is buff-gray, with dark gray hair tips. Lateral pelage is paler, and fewer hairs have dark gray tips. Colors of dorsal head and face are similar to dorsal body. White eye-ring is present, without intruding post-ocular patch. Venter is off-white or pale gray. Behind each ear, patch of buff hair extends onto nape of neck; it can be more conspicuous on individuals from northern parts of the distribution. Long pale hairs grow along anterior margin of each pinna, but otherwise pinnae are nearly hairless. Sparse hair covers tail, darker above than below. There is no tail tuft. Skin of plantar pes is black. 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 I 3/3, 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 = 30.

Habitat. Semiarid savanna woodlands among scattered boulders and kopjes and rocky outcrops with minimal vegetative cover but sometimes adjacent to relatively flat and sparsely vegetated compact sandy grounds. The Eastern Rock Sengishelters in cracks and crevices of rocks and boulders.

Food and Feeding. Insects, mainly ants and termites, are the principal diet of the Eastern Rock Sengi. Other small invertebrates and limited plant material are eaten. Foraging occurs from covered areas, with rapid emergence to seize prey. Larger insects (e.g. grasshoppers) are carried back to cover for ingestion; this is probably a risk sensitive behavior.

Breeding. The Eastern Rock Sengi is monogamous, and pairs mate forlife. In South Africa, births occur in September—March, corresponding with the warm, wet season. Male sperm are viable year-round, buttestes size and sperm count drop significantly when reproduction pauses during the cool season. Females can produce up to 89 ova per ovary per cycle, but limited uterus implantation sites constrain litter size. In Botswana and South Africa,litters have 1-2 young. Young are born with open eyes, fully furred, and highly precocial. Mothersvisit young infrequently for nursing, and there is no direct paternal care. Young females become sexually mature at 35-42 days. No species of soft-furred sengis use nests to shelter or for rearing their young.

Activity patterns. Eastern Rock Sengis are fully terrestrial. At the Weenen Game Reserve, South Africa, individuals are active at all hours (polycyclic) but are most active

and furthest from their home range center for periods of about five hours beginning at dusk and at dawn. Periods of least activity are overnight and during the afternoon.

Movements, Home range and Social organization. Home ranges of monogamous pairs overlap, but combined area has limited overlap with home ranges of neighboring pairs. Males and females of a pair infrequently interact except during estrus. If a male disappears, a neighboring male might engage in temporary polygyny during the vacancy. One study found that average home ranges were ¢.0-3 ha for males and c.0-2 ha for females, and maximum home range of males was c.1-3 ha. Monogamous mating system is probably a mate-guarding strategy. Limited home range overlap with neighboring pairs might indicate territoriality or at least mutual avoidance.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Eastern Rock Sengi is widespread, and its population trend is stable.

Bibliography. Corbet & Hanks (1968), Evans (1942), Olbricht & Stanley (2009), Perrin & Rathbun (2013e), Rathbun (2009, 2015e), Rautenbach & Schlitter (1977), Ribble & Perrin (2005), Tripp (1971, 1972), Woodall & Mackie (1987), Woodall & Skinner (1989).

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. Zimbabwe, W Mozambique, E Botswana, N, C & E South Africa, and N Swaziland; perhaps Lesotho.