It is widely accepted among the Cladocera (Crustacea) taxonomists that almost all cosmopolitan taxa are represented by some un-revised complexes of cryptic species. But many macro taxa of the cladocerans are still unrevised. The aim of this work is to analyze the taxonomic status of Oriental populations of the genus Bosminopsis Richard, 1895 (Anomopoda: Bosminidae) based on morphological characters. We have studied populations from India, Myanmar, Cambodia, Thailand, Laos, Vietnam, Philippines, Malaysia and Papua New Guinea and concluded that Oriental populations belong to a single species, Bosminopsis africanus (Daday, 1908), initially described from Africa. Analysis of literature data confirms that is widely distributed through whole Oriental zone. A single large mucro, or the mucro accompanied by an additional small spine in both sexes, is the main trait which differentiates B. africanus from B. zernowi Linko, 1901 distributed in more northern regions of Eurasia.
During recent years, many taxa of water fleas (Crustacea: Cladocera) with wide distribution ranges were revised and finally accepted as groups of cryptic species. Here we provide a redescription of Ilyocryptus raridentatus Smirnov, 1989 (Anomopoda: Ilyocryptidae). Our study clearly confirms that I. raridentatus belongs to the sarsi-group based on incomplete moulting, absence of dorsal keel, structure of antennule, thoracic limb I and postabdomen. The species is widely distributed in Australia and East Asia (Malaysia, Thailand, Vietnam, Central China, Japan, South Korea) and penetrates north to the Far East of Russia. A morphological variability among different populations of I. raridentatus does not exceed an intrapopulational level. I. raridentatus seems to be a relatively rare species with a benthic lifestyle similar to its congeners.