A new freshwater species (Bacillariophyta, Achnanthidiaceae) from Sichuan Province, China.

A new freshwater diatom species, Yu, You & Wang, from Sichuan Province, China, is described. The morphology of this species was analyzed with scanning electron microscopy (SEM) and light microscopy (LM). belongs to the -like subgroup, which has external distal raphe ends curved in opposite directions of the valve. The main characteristics of are its linear shape, rounded apices and transpically-elongated areolae on the both valves. The central area is well defined with one or two spaced striae of the raphe valve. And on the internal valve, areolae are occluded by hymens perforated by delicate slits, and each hymen is closely joined with the adjacent hymen. We compared the new species with other similar species of , is considered to be sufficiently different from other similar species based on valve outline, shape of the axial and center areas, and striae density. The new species is known only from its type locality, a mountain lake in Kangding County.