Morphology and Taxonomy of Marine Benthic Diatoms (17), Genus Neosynedra (Fragilariaceae, Fragilariales) (Part 1)

Abstract

The fine structure of a benthic diatom Neosynedra provincialis (Grunow) D.M.Williams & Round was examined using light and electron microscopy. The following morphological features of this species are first revealed in detail through the present study. Plastids, two per cell, are plate-like and rectangular immediately after cell division but form an H-shape as the cell contents grow and increase. The mature cingulum consists of six girdle bands, open at one pole, divided into two types: a valvocopula with two rows of areolae has a smooth edge (pars interior); five copulae with ligulae are thinner than the valvocopula. The morphological comparison between Neosynedra and Cyclophora reveals strong similarities in the shape of the colony and in the structure of the apical pore field and areola, which supports previous molecular phylogenetic analyses showing that both genera are closely related. (Continued from J. Jap. Bot. 99: 38–45, 2024)