LAUSR

ABSTRACT A phototrophic dinoflagellate belonging to the genus Scrippsiella was isolated from a water sample collected from Masan Bay, Korea. Using a clonal culture of this dinoflagellate, its morphology was analysed with light, scanning and transmission electron microscopy and small subunit (SSU), large subunit (LSU), and internal transcribed spacer ribosomal DNA (ITS rDNA) sequences were studied. The dinoflagellate plate formula was Po, x, 4ʹ, 3a, 7″, 6c (5c + t), 5s, 5ʹ″, and 2″″, consistent with Scrippsiella. The dinoflagellate had a rounded epitheca, unlike most Scrippsiella species, which have a conical epitheca. Furthermore, it had a narrow, symmetrical, and pentagonal 1ʹ plate, unlike other Scrippsiella species. In addition, it had three intercalary plates of different sizes. This species had noncalcareous cysts, unlike most Scrippsiella species, which have calcareous cysts. The LSU rDNA sequence of the dinoflagellate was about 2% different from Scrippsiella enormis, the closest Scrippsiella species, and the ITS rDNA sequence was about 8% different from S. enormis. The sequence was identical to an unidentified Scrippsiella strain from Chinese waters (SSND14) and 0.55% different from an unidentified Scrippsiella strain from Norwegian waters (GeoB 277). On the basis of its unique morphological and molecular features, this species was named Scrippsiella masanensis sp. nov.