Three new freshwater species of the genus Achnanthidium (Bacillariophyta, Achnanthidiaceae) from Taiping Lake, China

Abstract

We describe three new Achnanthidium species, A. lacustre sp. nov., A. sublanceolatum sp. nov., and A. taipingensis sp. nov., from Taiping Lake, Anhui Province (China) based on light and scanning electron microscopy. A. lacustre sp. nov. belongs to the "A. minutissimum complex" of the genus, based on it having straight external distal raphe fissures and round to elliptical areolae. Both A. sublanceolatum sp. nov., and A. taipingensis sp. nov. belong to the "A. pyrenaicum complex" of the genus, based on them having transpically-elongated areolae and deflected external distal raphe fissures. All three species are sufficiently different from other similar species based on valve outline, shape of the axial and center areas, and striae density. These three new species are all observed in benthic collections from Taiping Lake.