Chinia gen. nov.—the second diatom genus simonsenioid raphe from mangroves in Fujian, China

A new monotypic diatom genus Chinia gen. nov. from estuarine mangrove habitats in Fujian, China is described. Light, scanning and transmission electron microscopy observations of its morphology show that this diatom differs from any established raphid diatom genus. The new genus is distinguished by a strongly undulate valve face, eccentric raphe canal, and perforated copulae. Its distinctly elevated and perforated raphe canal, classified as simonsenioid type, is supported by sparse infundibulum-like portulae, and the portulae are separated by large fenestrae. The valves of Chinia also have hymenate areolar occlusions and the raphe lacks a central nodule. However, unlike most Bacillariaceae with two plastids, including Simonsenia, Chinia has a single plastid similar to those in Entomoneis and Surirella . Despite the similarities to Simonsenia, Chinia features porous raphe canal and loose striation, which is different from those of Simonsenia that has a solid raphe canal and distinct rows of areolae. These distinctive cytological and morphological characters suggest an affinity of the new genus to the Bacillariaceae.