This paper deals with the species of Brackionu.s plicatilis complex (Rotifera: Monogononta) found in a brackishwater lake, Veli-Aakulam, in Southern Kerala. Morphological and reproductive potential studies revealed that these rotifers have sigiificant morphological distinction with regard to ecological preferences. The three related rotifers in our study were classified as Brachionu. plicatilis Miiller, 1786, B. rotundiformi.s Tschugunoff, 1921 and B. murrayi Fadeew, 1925. The fine morphology and morphometric data revealed that taxonomic characters were constant enough to recognize three well-defined morphologies and B. murrayi is redescribed. The reproductive potential studies in relation to ecological parameters showed that the 'r' values of these rotifers were significantly influenced by salinity as well as temperature, and was species specific. In the light of reproductive preferences, the reorganization of three distinct species has been confirmed by this study and this would allow further comparative work in these lines on this economically important species complex.

Brachionus plicatilis species complex, reproductive preferences