Ctenophora hunanensis sp. nov. (Bacillariophyta) from the Yongle River in Hunan Province, China

A new species, <i>Ctenophorahunanensis</i> Bing Liu & Rioual, <b>sp. nov.</b>, found in the Yongle River, a tributary of the Xiang River (Hunan Province, southern China) is described on the basis of morphological observations made under light and scanning electron microscopes. <i>Ctenophorahunanensis</i> is distinguished from other <i>Ctenophora</i> taxa by a unique combination of characters that includes its lanceolate valve outline with rostrate apices, sternum gradually becoming wider from valve apices to center, and a greater valve width than the other members of the genus. <i>Ctenophorahunanensis</i> inhabits the epilithic community in the headwaters of a freshwater river. Many abnormal valves of <i>C.hunanensis</i> were observed in the samples investigated and the most frequent morphological abnormalities consisted in a lack of symmetry relative to the apical axis caused by a unilateral incising in the middle part of the valve.