Morphology, ecology and systematics of Cyclotella andina sp. nov. (Bacillariophyceae) from Lake Titicaca, Peru-Bolivia

Abstract

The morphology, ecology and systematics are described for a new diatom species, Cyclotella andina. It is only known to occur in the high Andean Lake Titicaca, a large and meso-oligotrophic tropical lake. There it often dominates during the winter mixing period. It is best distinguished from all other Cyclotella species by having a labiate process (rimoportule) and a marginal strutted process (fultoportule) on the same rib, a unique character among the freshwater members of the family Thalassiosiraceae. It cannot be classified within any of the present informal subdivisions of Cyclotella, and a new group is established based on this species and C. omarensis. Its closest morphological relatives within Cyclotella are only known from the fossil record.