Macroscelides micus, Dumbacher & Rathbun, 2014

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 : 229-230

8.

Etendeka Round-eared Sengi

Macroscelides micus

French: Sengi de I'Etendeka / German: Etendeka-Kurzohrriisselspringer / Spanish: Sengi de orejas redondas de Etendeka

Other common names: Etendeka Round-eared Elephant-shrew

Taxonomy. Macroscelides micus Dumbacher & Rathbun, 2014 ,

“ 20.7281°S, 14.1305°E at about 720 m above sea level ... about 10 km south by southwest (200°) of the Mikberg formation, Kunene District, [NW] Namibia.”

This species is monotypic.

Distribution. Etendeka Formation N & S of Huab River in NW Namibia.

Descriptive notes. Head-body 85-100 mm, tail 82-97 mm, ear 17-28 mm,

hindfoot 28-31 mm; weight 19-43 g. There is no evidence of sexual dimorphism in body size. The Etendeka Round-eared Sengi is round-bodied, with a round face. Tail length is ¢.95% of head-body length, short relative to other species of Macroscelides . Pinnae are broad, rounded, and shorter than on most species of Elephantulus . Snout is long, thin, and flexible. Hairis long, soft, and silky. Dorsal and lateral pelage is graybrown, with obvious rust-colored tinge, most prominent on face, rump, and tail. Hairs at distal end oftail are slightly longer and form rust colored tuft. Venteris off-white. Small but distinct patch of rust-colored fur occurs on each side of anus. Skin color of pinnae and limbs is pink, and hair on these areas is sparse. Prominent subcaudal gland, rust-colored fur, distinct perianal pattern, and pink skin of ears and limbs are diagnostic. There is no distinct eye-ring as occurs on many species of soft-furred sengis. 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 highly developed. Dental formulais13/3,C1/1,P4/4,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. Karyotype is unknown.

Habitat. LLow-gradient, rust-colored gravel slopes with scattered rocks and boulders and widely spaced perennial bunchgrasses, forbs, and few (if any) bushes taller than 30 cm at elevations of 340-860 m. Climate is hyper-arid with less than 20 mm of annual rainfall. The Etendeka Round-eared Sengi occurs in the Etendeka Formation between the coastal Namib Desert and the inland escarpment.

Food and Feeding. Given habitat and biological similarities with other species of Macroscelides , the Etendeka Round-eared Sengi is almost certainly omnivorous, with insects comprising the greatest proportion of the diet.

Breeding. The Etendeka Round-eared Sengi has small litters (probably 1-2) of highly precocial young. Breeding likely occurs year-round and perhaps with seasonal variability. Direct paternal investment is absent from all species of sengis that have been studied. No soft-furred sengis use nests to shelter or for rearing their young.

Activity patterns. Etendeka Round-eared Sengis are fully terrestrial and strictly nocturnal. Individuals shelter separately during the day under a single rock with a horizontal crevice as an entrance. One shelter is used per night, and the same shelter is rarely reused. Etendeka Round-eared Sengis tend to choose shelters where entrances face prevailing midday sun, perhaps a thermoregulation strategy. Shelters are entered near dawn and are notaltered (e.g. by digging or collected bedding).

Movements, Home range and Social organization. The Etendeka Round-eared Sengi is monogamous, and home ranges of male-female pairs overlap. Proportion of overlap probably depends on densities in suitable habitat. Average home range is conservatively estimated at c.7-2 ha. Foot drumming might be limited compared to other species of soft-furred sengis. There is no evidence thattrails are built or maintained.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Population trend of the Etendeka Round-eared Sengi is unknown.

Bibliography. Corbet & Hanks (1968), Dumbacher, Rathbun, Osborne et al. (2014), Dumbacher, Rathbun, Smit & Eiseb (2012), Evans (1942), Olbricht & Stanley (2009), Rathbun (2009), Rathbun & Dumbacher (2015a, 2015b).

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. Etendeka Formation N & S of Huab River in NW Namibia.