Cymbella stomachsis sp. nov. (Bacillariophyta; Cymbellaceae), a new species from Guangdong Province, China

A new diatom species from the genus Cymbella C. Agardh is described from samples collected during a survey of freshwater diatoms from Modaomen Channel, Guangdong Province, China. With the aid of light microscopy (LM) and scanning electron microscopy (SEM), we give a detailed morphological description of Cymbella stomachsis sp. nov., which is placed in the genus Cymbella according to the shared features of asymmetry about the apical axis, deflection of the external terminal raphe fissures towards the dorsal margin, and the presence of apical pore fields and stigmata. Although it shares some similar structural features with C. tumida, C. stuxbergii, C. stuxbergioides, C. pesudostuxbergii, C. mexicana and C. australica, C. stomachsis sp. nov. is easily distinguished by the valve outline, the shape and density of areola, and the appearance of a lack of an intermissio at the central nodule. Especially, the structure of the intermissio is absent in similar taxa. This work is important for its enrichment of our understanding of the genus Cymbella and improvement of the database of diatom biodiversity and distribution in China.