The Taxonomic Relations of the Atyidae (Decapoda: Caridea) of Sri Lanka Determined by Electrophoretically Detectable Protein Variation

Abstract

Electrophoretic variation at 29 loci in seven species and two subspecies of Sri Lankan atyid prawns (Caridina spp. and Atya sp.) was determined for samples of 12-24 individuals. Each species pair showed several fixed gene differences, and Nei's genetic distances of 0.279-1.748. The subspecies C. nilotica simoni and C. n. zeylanica showed no fixed gene differences and Nei's genetic distances of intraspecific interpopulation level (0.039). It is concluded from these data and the fact that these taxa are sympatric that C. n. zeylanica is only a population variant of C. n. simoni. A cladistic analysis using A. spinrpes as an out-group showed the genus Caridina in Sri Lanka to have two lineages, both of which have given rise to endemic species. It is suggested, on the basis of distributional data, that C. singhalensis, an endemic related to C. nilotica, C. gracilirostris, and C. typus, arose from an earlier colonisation and speciation cycle than C. pristis, an endemic allied to C. fernandoi (also endemic).