Macroscelides flavicaudatus, Lundholm, 1955

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 : 228-229

6.

Namib Round-eared Sengi

Macroscelides flavicaudatus

French: Sengi de Namibie / German: Namib-Kurzohrrisselspringer / Spanish: Sengi de orejas redondas de Namib

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

Taxonomy. Macroscelides proboscideusflavicaudatus Lundholm, 1955 ,

“ 6 miles [= 9- 6 km] from the mouth of the Omaruru River,” Swakopmund District, Namibia.

Macroscelides flavicaudatus was formerly a subspecies of M. proboscideus but elevated to full species by J. P. Dumbacher and colleagues in 2012. Monotypic.

Distribution. Namib Desert and pro-Namib in W Namibia.

Descriptive notes. Head-body 94-109 mm, tail 98-131 mm, ear 20-32 mm, hindfoot 32-38 mm; weight 22-39 g. There is no evidence of sexual dimorphism in body size.

The Namib Round-eared Sengi is roundbodied, with a round face. Tail is relatively long at c.110% of head-body length. Pinnae are broad, rounded, and shorter than most species of Elephantulus . Snout is long, thin, and flexible. Hair is long, soft, and silky. Dorsum is buff-gray and slightly lighter than on the Karoo Round-eared Sengi ( M. proboscideus ). Lateral pelage continues as buff-gray but with cream tinge. Venteris off-white. Tail hair is very short except for

terminal tuft. Tail color continues buff-gray of dorsum but becomesslightly darker toward tip. Hair color on head and face is similar to dorsum and flanks. There is no distinct eye-ring as 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 I 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 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 unknown.

Habitat. Gravel plains of the Namib Desert and pro-Namib, with very sparse vegetation and widely scattered bunchgrasses and low bushes. Climate is arid but coastal fogs supportlichens in these habitats. Namib Round-eared Sengis shelter among rocks and boulders, in shallow self-dug burrows, or in abandoned rodent burrows.

Food and Feeding. The Namib Round-eared Sengi is omnivorous and probably feeds primarily on insects and secondarily on herbage. As a former subspecies of the Karoo Round-eared Sengi ( M. proboscideus ), dietary proportions of the two are likely similar.

Breeding. Breeding characteristics of the Namib Round-eared Sengi are probably similar to the Karoo Round-eared Sengi. Litters probably have 1-2 young that are highly precocial at birth, with eyes open and mobility shortly after birth. Breeding probably occurs year-round and perhaps with seasonal variability. Direct paternal investment is absent from all species of sengis that have been studied, and no species of soft-furred sengis use nests to shelter or for rearing their young.

Activity patterns. Namib Round-eared Sengis are fully terrestrial. Activity is probably crepuscular, perhaps with some nocturnal tendencies.

Movements, Home range and Social organization. The genus Macroscelides is characterized by monogamous pairs, where males and females have overlapping home ranges. Proportion of overlap probably depends on densities in suitable habitat. Average home range is conservatively estimated at ¢.9 ha. Each member of a male-female pair probably spends most ofits time independently. Combined homes ranges of male—female pairs probably have very little overlap with home ranges of neighboring pairs. Foot drumming might be limited compared to other species of soft-furred sengis. Trail systems are built and actively maintained.

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

Bibliography. Corbet & Hanks (1968), Dumbacher, Rathbun, Osborne et al. (2014), Dumbacher, Rathbun, Smit & Eiseb (2012), Evans (1942), Olbricht & Stanley (2009), Perrin & Rathbun (2013h), Rathbun (2009), Rathbun & Dumbacher (2015a), Rathbun & Eiseb (2015).

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. Namib Desert and pro-Namib in W Namibia.