Abstract
In this study, we describe a new freshwater diatom, Navicula daochengensis sp. nov., which was found in a small mountain lake, Lake Congqiancuo, Haizishan Nature Reserve, Daocheng County, Sichuan Province, China. The detailed morphological description of the new species is provided from light and scanning electron micrographs. Navicula daochengensis has a narrowly lanceolate valve outline with broadly-rounded ends. The striate are radiate and convergent to the apices. This new species is compared with similar species, such as Navicula elongata, N. venerablis, N. moralesii and N. radiosa, which differ in size, valve shape, striae density and ultrastructure.