Cyclomorphosis in Daphnia carinata King (Crustacea : Cladocera) from Two Adjacent Sewage Lagoons in South Australia

Abstract

Seasonal changes in morphology are described for D. carinata from two adjacent sewage lagoons in South Australia. Carapace width to body length ratios of a variety of developmental stages showed carapace expansion in adults larger than 2 mm during times of the year when water temperature was decreasing. Carapace expansion was primarily dorsal in aspect. Several forms occurred concurrently during periods of morphological change. Cyclomorphosis in D. carinata is discussed in relation to studies on Holarctic Daphnia.