Macroscelides proboscideus (Shaw, 1800)

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 : 229

7.

Karoo Round-eared Sengi

Macroscelides proboscideus

French: Sengi a oreilles courtes / German: Kurzohrriisselspringer / Spanish: Sengi de orejas redondas de Karoo

Other common names: Karoo Round-eared Elephant-shrew, Round-eared Elephant-shrew, Round-eared Sengi, Shorteared Elephant-shrew, Short-eared Sengi

Taxonomy. Sorex proboscideus G. Shaw, 1800 ,

“ Cape of Good Hope” (= Roodewal) , Oudthoorn Division , Western Cape Province, South Africa .

In the past, M. p. proboscideus and M. p. flavicaudatus were subspecies, but both are now recognized as full species. Monotypic.

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

Descriptive notes. Head—body 104-115 mm, tail 107-134 mm, ear 20-25 mm, hindfoot 32-36 mm; weight 26-38 g. There is no evidence of sexual dimorphism in body size. The Karoo Round-eared Sengi is round-bodied, with a round face. Tail is relatively long at ¢.110% of head-body length. Pinnae are broad, rounded, and shorter than most species of Elephantulus . Snoutis long, thin, and flexible. Hair is long (up to 17 mm), soft, and silky. Dorsum is brown-gray and slightly darker than that of the Namib Round-eared Sengi (M. flavicaudatus). Lateral pelage is also brown-gray but with yellow tinge. Venter is off-white. Tail hairis very short except for terminal tuft; tail color continues brown-gray of dorsum but becomes slightly darker toward tip. Hair color on head and face is similar to dorsum and flanks. There is no distinct eye-ring as seen on many species of soft-furred sengis. Skin color of pinnae and limbs is nearly 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 1 3/3, C 1/1, P 4/4, M 2/2 (x2) = 40. Molariform teeth are more hypsodont in species of Macroscelides than in other extant species of sengis. Canine sizes are subequal to adjacent teeth. Auditory bullae are hyper-inflated. Several bilateral pairs of palatal foramina are present. Postorbital processes are absent. Karyotype is 2n = 26.

Habitat. Arid to semiarid gravel or compact sandy plains with scrub and scattered low bushes. The Karoo Round-eared Sengi shelters in patches of vegetation, shallow selfdug burrows, or abandoned rodent burrows.

Food and Feeding. The Karoo Round-eared Sengi is omnivorous and feeds primarily on insects and secondarily on herbage, with trace quantities of seeds and fruits. Diets vary seasonally and individually but generally contain 46-88% insects. Consumption of herbage is highest in winter. Relatively long cecum and more hypsodont dentition of species of Macroscelides are congruent with a diet that includes more plant material than other species of sengis.

Breeding. The Karoo Round-eared Sengi is monogamous. Breeding occurs yearround, but most pregnancies are during summer. Gestation is c¢.56 days. Females can produce 21 or more ova per ovary per cycle, but limited uterus implantation sites constrain litter size. Litters have 1-2 young, rarely three. Estrous cycles are c.10 weeks. Young are highly precocial at birth, with eyes open and mobility shortly after birth. Nursing occurs infrequently, perhaps once a day, and lasts c.2 weeks. Mothers provision their young with insects collected in their cheeks beginning at the end of the first week postpartum until the third week. There is no direct paternal investment. No species of soft-furred sengis use nests to shelter or for rearing their young.

Activity patterns. Karoo Round-eared Sengis are fully terrestrial. Activity is mainly crepuscular, with some nocturnal tendencies. Diurnal activity is very limited.

Movements, Home range and Social organization. Home ranges of monogamous pairs of Karoo Round-eared Sengis overlap. Proportion of overlap probably depends on densities in suitable habitat. Average home range is conservatively estimated at c.1-3 ha. Each member of a male-female pair probably spends most ofits time independently. Combined home ranges of male-female pairs generally do not overlap with ranges of neighboring pairs. Foot drumming might be limited compared to other species of soft-furred sengis. There is no evidence that trails are built or maintained.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Population trend of the Namib Round-eared Sengiis stable.

Bibliography. Asher & Olbricht (2009), Corbet & Hanks (1968), Dumbacher, Rathbun, Osborne et al. (2014), Dumbacher, Rathbun, Smit & Eiseb (2012), Evans (1942), Kerley (1995), Lawes & Perrin (1995), Olbricht (2009), Olbricht & Stanley (2009), Perrin & Rathbun (2013h), Rathbun (2009), Rathbun & Dumbacher (2015a), Rathbun & Smit-Robinson (2015a), Schubert et al. (2009), Tripp (1971), Woodall & Mackie (1987).

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. S Namibia, W South Africa (Northern Cape, Western Cape, and Eastern Cape provinces), and extreme SW Botswana.