Thin Mouse Shrew

Myosorex tenuis is a medium-sized shrew with dark fur. It is sometimes distinguished from other species of the genus by a smaller skull size, but species in this genus are typically difficult to morphologically identify due to significant intra-species variation. It is primarily separated from the similar M. cafer by genetic differences and habitat, and is estimated by Taylor et al to have diverged from its nearest genetic relative, M. varius, approximately 2.7 million years ago. A 2023 climatic niche modelling study proposes that the divergence from M. varius was due to habitat contraction during a interglacial cycle; the divergence roughly coincided with the start of the Pleistocene glacial cycles. The species habitat is Afromontane grassland, and they are more common at higher elevations. Specimens have primarily been collected from wetlands and moist grassland. The species was originally identified in Wakkerstroom District, Mpumalanga Province, South Africa, while the species identified by Taylor et al provisionally identified with M. tenuis is found in Limpopo Province, South Africa. The species range may reach Eswatini and Mozambique. Due to its limited range and the loss and fragmentation of grassland habitat, the species is considered endangered, though there is no clear estimate of its population numbers. Modelling by Taylor et al. …