Morphology and phylogeny of Lissodinium schilleri Matzenauer (Dinophyceae), a non-cingulum-bearing dinoflagellate

Abstract

In contrast to the typical peridinioid dinoflagellates, the family Podolampadaceae is characterized by the absence of both a cingulum and a depressed sulcus. The genus Lissodinium is the largest genus within this family, currently including 18 species. However, species of the genus Lissodinium have only been observed in fixed samples, yet they remain poorly known because they have always been recorded at extremely low abundances. Until now, the live cell and molecular data of Lissodinium were not available. In this study, we re-examine the morphological features of L.schilleri collected from the East China Sea and Korean coastal waters, and present the first phylogenetic analyses based on SSU rDNA, ITS region (ITS1-5.8S-ITS2) and LSU rDNA gene sequences from single specimens. Cells of L. schilleri are approximately pebble-shaped, 29&#8211 40 μm in length and 24&#8211 35 μm in width. The nucleus is oval-shaped, about 25 μm long and 13 μm wide, positioned dorsally near the center of the cell. A large red pigment body is present near the position of the nucleus. The thecal plate pattern is APC, 3, 1a, 5, 4c, 5s, 5, 3. The thecal surface is smooth many small pores are randomly distributed on the thecal surface which maybe round or elongated. Molecular phylogenetic analysis using SSU rRNA gene sequences shows that L. schilleri is allied with other podolampadaceans. Concatenated phylogeny reveals t 18 species. However, species of the genus Lissodinium have only been observed in fixed samples, yet they remain poorly known because they have always been recorded at extremely low abundances. Until now, the live cell and molecular data of Lissodinium were not available. In this study, we re-examine the morphological features of L.schilleri collected from the East China Sea and Korean coastal waters, and present the first phylogenetic analyses based on SSU rDNA, ITS region (ITS1-5.8S-ITS2) and LSU rDNA gene sequences from single specimens. Cells of L. schilleri are approximately pebble-shaped, 29&#8211 40 μm in length and 24&#8211 35 μm in width. The nucleus is oval-shaped, about 25 μm long and 13 μm wide, positioned dorsally near the center of the cell. A large red pigment body is present near the position of the nucleus. The thecal plate pattern is APC, 3, 1a, 5, 4c, 5s, 5, 3. The thecal surface is smooth many small pores are randomly distributed on the thecal surface which maybe round or elongated. Molecular phylogenetic analysis using SSU rRNA gene sequences shows that L. schilleri is allied with other podolampadaceans. Concatenated phylogeny reveals t