Environmental factors such as temperature are known to affect growth process in non-marine ostracods. Accordingly, the occurrence of changes in shape due to environmental cues is expected but poorly documented. Here we assess changes occurring in a clonal. lineage -genetically uniform- of the non-marine ostracod Heterocypris barbara. Adult carapace size and shape have been analysed for a series of ostracods raised under controlled conditions for three environmental factors (two levels each): photoperiod - 16:8 and 8:16 (L:D) - , temperature - 10° and 20°C - and conductivity - 6 and 20 m. S cm~l . Relative influence of each of those factors and the interactions between them are described. Implications for the reconstruction of palaeoenvironments and for evolutionary ecology of partheno genetic ostracods are discussed.