The first description of the male and ephippial female of Dadaya macrops (Daday, 1898) (Cladocera, Chydoridae), with additional notes on this common tropical species
Males and ephippial females of Dadaya macrops (Daday), a widely distributed tropical cladoceran, are described for the first time together with hitherto unrecorded morphological features of the parthenogenetic female. The postabdomen of the male is unique among chydorids in having only a vestige of the terminal claw. This confirms the validity of this monotypic genus. The material studied comes from Sri Lanka (Ceylon), taken in the neighbourhood of the type locality. Our description provides a detailed morphological record of a population containing all instars of males and females, and both parthenogenetic and ephippial adult females. Type material of parthenogenetic females, the only forms hitherto known, agrees closely with our material. An analysis of the population structure is given.