Cell division and reformation of the amphiesma in the pelliculate dinoflagellate,Heterocapsa niei

Abstract

Cytokinesis is described for the first time in a pelliculate dinoflagellate that retains its thecal plates during cell division. In Heterocapsa niei cytokinesis proceeded in a manner that differed from that described for other dinoflagellates. The thecal plates separated along the fission line before the development of a cleavage furrow. A distinct cleavage furrow developed as cytokinesis progressed. The outer membrane and the outer plate membrane expanded during division to enclose the enlarging cell undergoing cytokinesis; however, as the cleavage furrow deepened, these membranes were not continuous with the cytoplasm. The pellicle was occasionally intermittent in the region of the cleavage furrow, possibly facilitating movement of material from the cytoplasm to the developing outer membranes. Thecal plate formation occurred within the thecal vesicle from unrecognizable precursors.

Taxonomy and identification of the armored dinoflagellate genus Heterocapsa (Peridiniales, Dinophyceae)

“…For example, H. orientalis, H. ovata and H. pseudotriquetra are spherical and quite similar to each other, but only H. orientalis has its nucleus in the hypotheca (Iwataki et al 2003(Iwataki et al , 2004. Among the ellipsoidal species, the nuclei of H. niei, H. psammophila and H. pygmaea are located in the hypotheca, whereas that of H. horiguchii is positioned in the epitheca , Morrill & Loeblich III 1984, Iwataki et al 2002a, Tamura et al 2005. The nuclei of H. circularisquama and H. illdefina are elongated through the cell (Herman & Sweeney 1976, Horiguchi 1995; therefore, they are difficult to distinguish from each other based on the nuclear position.…”

Cellulose Synthesis Is Coupled to Cell Cycle Progression at G1 in the Dinoflagellate Crypthecodinium cohnii

“…The increase of CFW signals at T ϭ 10 was caused by the increased percentage of G 2 /M cells from approximately 30% to approximately 70%. Morrill and Loeblich (1984). The amphiesma consists of a continuous outermost membrane (the plasma membrane), the outer plate membrane, and a single-membrane-bounded thecal vesicle.…”

Morphological and molecular characterization of the small armoured dinoflagellateHeterocapsa minima(Peridiniales, Dinophyceae)

“…Species currently assigned to Heterocapsa have repeatedly been shown to form a monophyletic group (Yoshida et al, 2003;Zhang et al, 2007;Stern et al, 2012) that is poorly resolved relative to other Peridiniales groups and sometimes occupies a basal position (Saldarriaga et al, 2004;Zhang et al, 2007). Furthermore, species of Heterocapsa have been shown to divide by desmoschisis (Morrill & Loeblich, 1984) which is quite uncommon within the Peridiniales (Tillmann & Elbrächter, 2013), the sulcal plates are somewhat atypical (Saldarriaga et al, 2004) and the earliest fossils of the family are recorded prior to the radiation of other Peridiniphycidae (Fensome et al, 1993).…”