Species of the cyprinid genus Garra in Mount Kenya, East Africa: Species delineation, taxonomy and historical biogeography

The cyprinid genus Garra is so far represented in Mount Kenya streams by a single species, but which species it should be referred to as remains yet to be determined. Molecular phylogenetic analysis of Garra species from the mountain is still lacking. Here, an integrative analysis, based on morphological and molecular data, unravelled the hidden species diversity of Garra from Mount Kenya. In mitochondrial genes-based trees, samples formerly identified as Garra dembeensis from the mountain nested into three distinct lineages that were distantly allied to the lineage constituted by topotypical samples of the species; the three lineages are morphologically distinguishable, and thus represent three distinct species: Garra hindii and two undescribed species, herein named as Garra alticauda sp. nov. and Garra minibarbata sp. nov., respectively, from the Mara River and the Ragati River of the mid-upper Tana River basin. The phylogeographic pattern of the three species is incongruent with the present-day basin pattern of Mount Kenya. The allopatry of the paired species G. alticauda and G. hindii points to river piracy ever incurring between the upper Ewaso Ngiro River and the middle Tana River basin in Mount Kenya. Besides, the molecular phylogenetic analysis of sampled African Garra species in this study, based on a broad set of sequences, provides evidence in support for the existing hypothesis of Asia-to-Africa biodispersal via the Arabian Peninsula to the Horn of Africa.