Probing hidden diversity to enhance conservation of the endangered narrow-range endemic Eastern Cape rocky, Sandelia bainsii (Castelnau 1861)

Accurate delimitation of species boundaries is a fundamental requirement for formulating environmental policies and spatial conservation planning to prevent loss of biodiversity (e.g. Nel et al. 2011). However, because morphological differences may remain undetected as a result of their subtlelty and the experience or expertise of the observer, there are several cases where two or more morphologically similar species have been mistakenly classified into a single taxon, thus compromising conservation of rare, cryptic and narrow-range species (Bickford et al. 2007). The use of molecular data has resulted in the discovery of new species and several historically isolated lineages within many groups of freshwater fishes that were previously considered to be single wide-ranging species. This is particularly true for the Cape Fold freshwater ecoregion (CFE) in South Africa and the Eastern Zimbabwe Highlands freshwater ecoregion (EZH), where new species, unique lineages and taxonomic conflicts have been discovered in various species groups (e.g. Bronaugh, Swartz & Sidlauskas 2020; Chakona et al. 2018a; Chakona, Swartz & Gouws 2013; Swartz, Skelton & Bloomer 2009; Wishart et al. 2006). Such findings have stimulated renewed interest in the systematics and taxonomic revisions of freshwater fishes in southern Africa (e.g. Chakona & Skelton 2017; Chakona & Swartz 2013; Chakona, Swartz & Skelton 2014; Maake, Gon & Swartz 2014). This information has also been critical in guiding accurate International Union for Conservation of Nature (IUCN) redlist assessments for freshwater fishes in South Africa (Chakona et al. in prep).