LAUSR

The freshwater caridean genus, Caridina H. Milne Edwards, 1837, is one of the most taxonomically challenging genera within Caridea. Not only does the genus contain around 300 species, a daunting number and thus taxonomically challenging by itself. Historically however, numerous poor descriptions by modern standards abound, often erecting species on what are now known to be variable characters, such as rostral length (e.g., de Mazancourt et al., 2017a). Further, many species, both historically as well as recently described, remain only known from their (often small) type series, confounding a lack of knowledge about intraspecific variation. In recent years, Caridina research has moved more towards integrative taxonomy, with taxa described on the basis of a combination of morphological characters, genetic distinctness and even colour patterns (e.g., Von Rintelen & Cai, 2009; Klotz & Von Rintelen, 2014) or indeed taxa being synonymized following the same multiple lines of evidence (de Mazancourt et al., 2017b). Unavoidably perhaps, several recent descriptions remain solely focussed on morphological characters, due to the absence of molecular grade material for many species, a problem not restricted to Caridina! Despite much effort devoted to Caridina over many decades by numerous devotees, much environmental and biological data is also lacking, especially in the Afrotropical Region. In a recent IUCN Red List assessment (De Grave et al., 2016), 41.0% of freshwater shrimps (including Macrobrachium Spence Bate, 1868 in that percentage) from that region are considered to be Data Deficient, largely on the basis of taxa only known from material collected pre-1950 (although often described since then), with scant details on type locality, further distribution and threats.