Lin H.N., Wu W.W., Sun L., Witkowski A., Li X.Y., Patil V., Liang J.R., Li X.S., Gao Y.H. and Chen C.P.. Journal of Oceanology and Limnology, DOI: 10.1007/s00343-021-1067-0.

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.

Figure 1. SEM images of Chinia longhaiensis gen. et sp. nov.

a. valve internal view with undulate surface, illustrating the position of fi bulae (white arrow); b. close-up of the specimen illustrated in (a); note the presence of tiny spinules on infundibulum-like surface (white arrowhead) and the undulate valve; c. external view of the whole valve with the slightly displaced and elevated canal raphe; d–e. close-up of the valve apical part illustrating the apical raphe fi ssure termination (black arrowheads); f. raphe canal apical end clearly illustrating the presence of helictoglossa (black arrow) and portula (white arrow). Scale bars: 5 μm (a, c, d, e); 3 μm (b, f).