Thalassiosira and related taxa i.e. the taxa within Thalassiosirales are among the most abundant and widespread diatoms. The vast majority have one marginal rimoportula, but very few always have two. The knowledge on Thalassiosiroid taxa in Chinese waters is restricted, and to explore the diversity, monoclonal strains were established from southern Chinese coastal waters. Morphological data were based on light and scanning electron microscopy. The D1‒D3 region of the ribosomal large subunit (LSU) and the...