Cryptic diversity in forest shrews of the genus <italic>Myosorex</italic> from southern Africa, with the description of a new species and comments on <italic>Myosorex tenuis</italic>

Abstract

Forest or mouse shrews (Myosorex) represent a small but important radiation of African shrews generally adapted to montane and/or temperate conditions. The status of populations from Zimbabwe, Mozambique, and the north of South Africa has long been unclear because of the variability of traits that have traditionally been ‘diagnostic’ for the currently recognized South African taxa. We report molecular (mitochondrial DNA and nuclear DNA), craniometric, and morphological data from newly collected series of Myosorex from Zimbabwe (East Highlands), Mozambique (Mount Gorogonsa, Gorongosa National Park), and the Limpopo Province of South Africa (Soutpansberg Range) in the context of the available museum collections from southern and eastern Africa and published DNA sequences. Molecular data demonstrate close genetic similarity between populations from Mozambique and Zimbabwe, and this well-supported clade (herein described as a new species, Myosorex meesteri sp. nov.) is the sister group of all South African taxa, except for Myosorex longicaudatus Meester & Dippenaar, 1978. Populations of Myosorex in Limpopo Province (herein tentatively assigned to Myosorex cf. tenuis) are cladistically distinct from both Myosorex varius (Smuts, 1832) and Myosorex cafer (Sundevall, 1846), and diverged from M. varius at approximately the same time (2.7 Mya) as M. cafer and Myosorex sclateri Thomas & Schwann, 1905 diverged (2.4 Mya). Morphometric data are mostly discordant with the molecular data. For example, clearly distinct molecular clades overlap considerably in craniometric variables. On the other hand, extreme size differentiation occurs between genetically closely related populations in the Soutpansberg Range, which coincides with the bissection of the mountain range by the dry Sand River Valley, indicating the potential for strong intraspecific phenotypic divergence in these shrews. © 2013 The Linnean Society of London