Stomatocysts of Mallomonas hamata and M. heterospina (Mallomonadaceae, Synurophyceae) from South Swedish lakes

摘要

The stomato cysts ofMallomonas hamataandM. heterospinaare described from lakes in South Sweden. TheseMallomonasspecies develop cysts of similar appearance, size and form. Cyst formation forMallomonas hamatawas recorded at temperature 10–11°C and pH 5.9 and forM. heterospinaat temperatures 4.2–11°C and pH 7.4. The cysts ofM. hamataandM. heterospinaare ovoid and easy to recognize, even with light microscopy, but difficult to distinguish from another. Thus their value as paleoindicators is limited, even if the two species have preference for waters of different nutrient and pH s