The marine diatom genus Thalassiosira species (Bacillariophyceae) from coastal waters of Korea

Abstract

The diatom Thalassiosira species are known to about 100 species in the marine ecosystem. The present taxonomic study revelaed the presence of at least 16 taxa from Korean coastal waters; Thalassiosira allenii, T. concaviscula, T. curviseriata, T. eccentrica, T. lundiana, T. mala, T. minuscula, T. nodulolineata, T. nordenskioeldii, T. pacifica, T. proschkinae, T. punctigera, T. rotula, T. tenera, T. weissflogii, and new recorded Thalassiosira sp.. These species were morphologically observed not by means of LM and SEM, but also their molecular relationship were examined by analysis of LSU region(D1-D3). In morphology, the shape of external tube of marginal strutted processes is a critical feature of Thalassiosira species. There 16 species are classified 8 groups due to the feature of external tubes. The 1st group is \\\\'flame\\\\' shape in T. allenii, T. concaviscula, T. nordenskioeldii, and T. pacifica. The 2nd group is short \\\\'straw\\\\' shape in T. eccentrica, T. lundiana, T. nodulolineata, and T. rotula. The 3rd group is \\\\'tooth\\\\' shape in T. tenera. The 4th group is \\\\'tulip\\\\' shape in T. punctigera. The 5th group is \\\\'T\\\\' shape in T. curviseriata. The 6th group is \\\\'pile\\\\' shape in T. weissflogii. The 7th group is simple hole (no development of external tube) shape in T. mala, T. minuscula, and T. proschkinae. Judging from barnacle shapes of Thalassiosira in the last group, it is new species. By the structure of external tube of the genus Thalassiosira, taxa were a distinctive character for identification. In molecular study, LSU region shows that their relationship basis of the external tube. Particularly, the \\\\'falme\\\\' shape species are strongly supported. Therefore, we anticipate that the external tube of marginal strutted processes is related to molecular relationship.