Beryl A. Bwong

The species richness of flora and fauna in the Nzoia River drainage basin is documented through a study of museum specimens, catalogues and databases. The catchment area and basin covers 2.2% (12900/580367 km2) of Kenya's total land area with an altitudinal range of 1140 to 4300 m and varied ecosystem and land uses. We recorded approximately 9.3% (3239/34677) of Kenya's current known species of vascular plants, invertebrates (insects and spiders), fish, amphibians, reptiles, birds and mammals. Bird species made up the highest proportion 58.3% (650/1114) of the national total followed by amphibians 37.3% (41/110), reptiles 45.0% (86/191), mammals 31.3% (122/390), vascular plants 17.9% (1251/7000), fish 6.7% (58/872) (32.2% (58/180) for freshwater fish only) and invertebrates (insects and spiders) 4.1% (1031/25000). Ninety-five species recorded in this area are endemic to Kenya and 42 globally threatened. The species recorded contribute to several ecosystem services including pest control, pollination, bio-indicators, medicine and cosmetics, building materials, ecotourism, research and education. Data available differed substantially across counties and taxon groups with gaps apparent in five counties (Bungoma, Busia, Elgeyo Marakwet, Siaya and Usain Gishu) and four taxa plants, invertebrates, fungi and bacteria where a dearth of information exists. To fill these gaps we recommend prioritisng future survey effort on taxa and counties with fewer than 10% of the total numbers of records.

The taxonomic validity of the East African reed frogs Hyperolius mitchelli Loveridge, 1953 and Hyperolius rubrovermiculatus Schiøtz, 1975 has been questioned in the literature, with the latter having been recognised as a distinct lineage, but also synonymised as a colour variant of H. mitchelli. The recent description of a new closely related congener from Mozambique, Hyperolius stictus (Conradie et al., 2018), along with evidence of genetic differentiation within H. mitchelli has suggested that this widely distributed species might be a species complex. In this study, we reassess the relationships of these closely related species with new field sampling, molecular, morphological and bioacoustics analyses with the aim to assign the correct taxonomic identity to H. cf. mitchelli from northern Tanzania. Our results demonstrate that there are four distinct lineages within this group: H. stictus from Mozambique; H. rubrovermiculatus from southern Kenya; H. mitchelli sensu stricto from central and southern Tanzania and Malawi and H. cf. mitchelli from north-eastern Tanzania. Based on our combined analyses we assign H. cf. mitchelli as a new population of H. rubrovermiculatus with distinct colouration, extending the range of this species from Kenya into northern Tanzania. We also clarify the genetic, morphological and acoustic variation within and between all lineages to further knowledge of this group and provide direction for future study into this fragmented and variable lineage.