Two new species of Cymbella (Bacillariophyceae) from China, with comments on their valve dimensions
2020
Liu, Bing | Williams, David M. | Li, Yan | Tang, Zhong-Sen
Two new species of Cymbella, Cymbella stigmacentralis sp. nov. and C. compactiformis sp. nov., are described. Both C. stigmacentralis and C. compactiformis have a wide size range, with distinctive valve outlines that change markedly from the largest to the smallest. They also occasionally show one or two stigmoid-like pores on their dorsal (secondary) side. Cymbella stigmacentralis and C. compactiformis share features of the apical pore field: a complete area which is not divided by the distal raphe fissure; round foramina arranged in parallel; each pervalvar row of foramina covered internally by an undulate flap-like silica strip. Based on the characteristics of these two new species that lack a constant valve outline, and their fine morphological structures, it is worth studying species of Cymbella more intensively.
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