Three Rumanian Mallomonas species (Synurophyceae), with special distribution patterns

Abstract

Mallomonas is the largest genus of the Synurophyceae (chrysophytes) and includes more than 120 species. Most of them are cosmopolitan, living in freshwater habitats. The Rumanian taxa occur usually in spring or early summer at water temperatures ranging between 4 ° and 10 °C. They are most frequent in neutral or slightly acid, clear-watered, aquatic habitats of various types. However, Mallomonas paludosa Fott appears mostly in brown watered peatbog pools of low mineral contents, having a particular geographical area, with its southernmost limit in the Rumanian Eastern Carpathians. Its distribution, like that of other boreal elements, is strictly connected with the occurrence of genuine ombrogenic Sphagnum-bogs, which have their southern limit also in Romania. The other two species dealt with — M. cyathellata Wujek & Asmund and M. portae-ferreae Péterfi & Asmund —, occurring in circumneutral or moderately alkaline waters of eutrophic character, are apparently warm water forms, mostly distributed in tropical, subtropical or mediterranean zones. The Rumanian localities (in the Danube Delta and at Eşelniţa near the Danube, up stream Drobeta Turnu-Severin) might be the northern limits of M. portae-ferreae in Eastern Europe. The Danube Delta is the only locality of M. cyathellata in Europe, and its northernmost occurrence as well. The occurrence of both species in Rumania is presumably due to migratory waterfowl.