Two new species of Gogorevia (Achnanthidiaceae, Bacillariophyceae) from Mongolia and Russia

Two new species of Gogorevia are described from Mongolia and Russia. Gogorevia mongolothermalis, found in a hot spring in Mongolia, was studied with light and scanning electron microscopy as well as molecular methods. Morphologically it is distinguished from similar taxa by a narrow rectangular valve outline with capitate ends, stria density and a well-developed stauros on the raphe valve. On the phylogenetic tree strains of G. mongolothermalis form an independent branch inside the clade of other Gogorevia species. The other new species, Gogorevia similis, found in a freshwater lake in Moscow Region, is described based on morphological analysis. It is differentiated from similar species by a characteristic widely rectangular outline and a bow-tie-shaped stauros. Ecological preferences of Gogorevia representatives are discussed as well.