Caridinian Shrimp Resources of Kerala Waters (Decapoda, Atyidae)

The paper discusses on the freshwater shrimp resources of the genus Caridina H. Milne Edwards of Kerala waters based on the collections from 41 research stations including estuarine regions, freshwater and hill streams. The study revealed certain interesting aspects. C. williamsoni Jalihal et al. 1984, C. gurneyi Jalihal et al. 1984, C. shenoyi Jalihal et al. 1984, C. kempi Jalihal et al. 1984 are new records from Kerala waters, of which the last two species are being recorded out of the type locality for the first time. The paper also presents an extensive distributional range (new records) for other species of the genus within the state. Only four species have been reported from backwaters of Kerala, namely, C. pseudogracilirostris Thomas et al. 1973, C. kempi Jalihal et al. C. nilotica (Roux 1833) and C. weberi var. sumatrensis de Man 1892 and excepting the first their abundance is very poor. C. williamsoni is a common species in the freshwater zone. C. natarajani Tiwari and Pillai 1968 is confined to the southern regions of the state. The specimens of C. nilotica collected during the present study could not be identified to any of the varieties recorded so far and hence needs further investigation. C. kempi has been reported very rarely from brackish waters (Valapattanam backwater, abundant). The species, C. gracilirostris de Man 1892, C. laevis Heller, 1862 and C. nilotica var. veliensis Pillai 1964, recorded earlier could not be collected during the present study. C. kempi and C. shenoyi are rare species in Kerala waters. The paper also provides valuable diagnostic characters as well as a key for the identification of the species.