Phylogenetic relationships within the genus Daphnia (Cladocera : Daphniidae) in Australia, determined by electrophoretically detectable protein variation

Abstract

Phenetic and cladistic analyses of allozyme variation at 11 loci in five of the six Australian species of Daphnia showed D. (Daphnia) occidentalis to be more distantly related to each of the Daphnia species from the subgenus Ctenodaphnia (Nei's genetic distance D = 0.49-0.84) than a given Ctenodaphnia species was to other members of the same subgenus (Nei's D between species pairs ranging from 0.31 to 0.61). Two of the three members of the Daphnia carinata complex in Australia, D. carinata and D. nivalis, were closely related (D = 0.16). The remaining member of the complex, D. cephalata, was not demonstrably more closely related to this pair of species than to D. lumholtzi, the only other member of the Daphnia subgenus Ctenodaphnia occurring in Australia. The distant relationship of D. cephalata and D. carinata contrasts with traditional views, and with evidence of continued hybridization between these taxa, but is consistent with the results of recent detailed morphological studies.