Integrative taxonomy within the Hylomyscus denniae complex (Rodentia: Muridae) and a new species from Kenya

Abstract

A new species of African wood mouse (Hylomyscus) is described from the western Kenya region. Previous studies have hypothesized that populations of Hylomyscus from this region may be assignable to either H. vulcanorum or H. cf. anselli. We compared 3 populations of Hylomyscus from western Kenyan montane forests to sister taxa from the Hylomyscus denniae group on the basis of morphology, morphometrics, mitochondrial DNA gene trees, multilocus species trees, and coalescent-based species delimitation to clarify relationships within these clades. Our results were congruent across data sets in support of this new species as sister to H. anselli and reproductively isolated from H. endorobae on the Mau Escarpment of Kenya where the 2 taxa are sympatric and syntopic. Lineages within the H. anselli group differ by 3.2-7.4% in (corrected) cytochrome-b sequences. Phylogeographic analysis of Hylomyscus n. sp. suggests strong population or range expansion, or both, since the last glacial maxima. A dated multilocus species tree places divergence of Hylomyscus n. sp. from H. anselli during the middle Pleistocene and the H. anselli group from the H. denniae group during the late Miocene to early Pliocene. This species is known from protected sites on Mt. Elgon, as well as unprotected sites within the Mau Escarpment and Cherangani Hills where extensive human habitat disturbance warrants conservation attention. © 2014 American Society of Mammalogists.