Morphology, Molecular Data, and Fatty Acid Composition of Some Monoraphid Diatoms from the South China Sea, with Description of Two New Species of Astartiella

We examined 13 strains of marine monoraphid diatoms belonging to the genera Schizostauron, Astartiella, and Achnanthes, isolated from the South China Sea near Viet Nam, with the use of light, fluorescent and electron microscopy, and molecular methods. Based on our investigation, two new species of Astartiella are described: Astartiella triundulata and Astartiella zinaidae. A morphological comparison with close species is provided, and the results of molecular analysis are discussed. Schizostauron strains were identified as S. trachyderma: the cryptic diversity and genetic variability within this genus are examined. Data on geographical distribution of these taxa are presented. A total fatty acid profile was obtained for both Schizostauron and Astartiella strains, and the results are discussed as well.