Species
Mus imberbis
Description
Mus imberbis Rüppel, 1842
It is an easily distinguished taxon, very large compared to other Nannomys (sequenced individual weighted 25 g) and with a black dorsal stripe. It was previously considered as a separate genus Muriculus, but genetic analysis clearly showed that it is an internal lineage of Mus (Meheretu et al. 2015). It is an endemic species of the high plateaux of Ethiopia, known only from a few individuals. Until the study of Meheretu et al. (2015), only 34 specimens of this species had been known, 12 of them captured before 1940 (Yalden 2013) and the remaining 22 reported by a single study (Assefa & Zerihun 1980; unfortunately, no vouchers from this study were preserved, so the species identification cannot be confirmed). The type locality of this species is characterized as open upland grasslands in the Semien Mts., at 2800 m a.s.l. Assefa & Zerihun (1980) collected the species from bushes and grassland habitats at the edges of farmlands close to streams, between 2490 and 2900 m a.s.l. Some specimens have also been collected from anthropogenic habitats around the type locality (Yalden et al. 1996). The specimen reported by Meheretu et al. (2015), as well as recently collected material from Mt. Chilalo (Kostin et al. 2019) and Semien Mts. (Craig et al., in lit.), were all collected in fragmented ericaceous shrub growth, suggesting that this species might have a wider ecological distribution than previously thought. However, because several attempts to trap the species from its presumed natural habitats have not been successful, including the extensive sampling from 1968 to 1998 by Yalden and colleagues, it has been suggested that the species has become rarer in its natural habitat since 1940 in response to habitat destruction (Yalden et al. 1976, 1996, Lavrenchenko & Schlitter 2008). Assefa & Zerihun (1980) captured most of the specimens by flooding burrows with water, and they stated that the species was not attracted to peanut butter bait and was rarely captured in snap traps even at localities where flooding was very successful. Two recent specimens in the Arsi Mts. (Meheretu et al. 2015, Kostin et al. 2019; both at 3200 m a.s.l.) were captured in a snap trap and a Sherman live trap, respectively, while in the Semien Mts. (Craig et al., in lit.; 3250 and 3600 m a.s.l.) the species was captured in Sherman traps (n = 2) and pitfall traps (n = 2). The low trapping success by conventional methods may also be related to its partly fossorial lifestyle (Yalden 2013).
Taxonomy
Mus imberbis is a species. It belogs to the Muridae family.
