Description of Limnomonas gen. nov., L. gaiensis sp. nov. and L. spitsbergensis sp. nov. (Chlamydomonadales, Chlorophyta)

Abstract

Two novel Chlamydomonas-like species, belonging to the Moewusii clade, have been described. The first species inhabits eutrophic and neutral to basic pH waters in Sweden and England. It is easily recognizable under a light microscope due to its morphology (a small green prolate spheroidal shape with a large and truncated papilla at its anterior end, two equal flagella, a single lateral eyespot, a basal nucleus, and a well-defined pyrenoid) and to its peculiar whole-body pendulum movement while resting on surfaces or attached to floating particles. The species occurs as free-living individuals and is able to gather temporarily into groups of individual cells. No particular binding structures or palmelloid cells were observed in cultures. The second species, previously assigned to Chlamydomonas cf. proboscigera, was collected from persistent snow in Svalbard, Norway. Its morphology is revised herein. Using SSU rDNA sequence analyses, these two species formed a well-supported clade. Moreover, ITS-2 secondary structure analyses confirmed sexual incompatibility between these biological species. Considering these results, a new genus Limnomonas and its type species L. gaiensis and L. spitsbergensis are proposed.