Otomys cf. karoensis, Roberts, 1931

Taylor, Peter John, Kearney, Teresa, Dalton, Desire Lee, Chakona, Gamuchirai, Kelly, Christopher M. R. & Barker, Nigel P., 2020, Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys), Zoological Journal of the Linnean Society 189, pp. 1046-1066 : 1063

Otomys cf. karoensis sp. 1 clade

Vlei rat species show extreme morphological conservatism, which makes them difficult to identify in the field. Small, pallid-coloured specimens from the Sneeuberg Range (preset study) and Tiffendell (from the study by Phukuntsi et al. 2016) were genetically distinct from O.auratus , O.irroratus and O.sloggetti and from O. karoensis s.s. Morphometric and craniodental analysis ( Fig. 3 and Results above) confirm their specific separation from these four species, highlighting the crucial importance of retaining museum voucher specimens in molecular studies, especially in the case of cryptic species. We describe this new O. cf. karoensis sp. 1 lineage as O. willani above. This result confirms our hypothesis, based on the cryptic speciation observed in O. irroratus s.l. ( Engelbert et al., 2011), that co-occurring O. karoensis s.l. would also show evidence of speciation between grassland and fynbos biomes from the Southern Escarpment and Cape Fold Belt mountain ranges, respectively. The drivers of this speciation were therefore probably the same for both species complexes and are described below for the O. irroratus – O. auratus clade.