A survey of thecal fine structure in the Dinophyceae

Abstract

The structure of the theca of some 30 marine and freshwater members of the Dinophyceae has been examined by light and electron microscopy. The basic arrangement of membranes, an outer continuous plasma‐membrane beneath which lies a single layer of flattened vesicles, is the same in all flagellated forms. The periplast of coccoid and encysted forms is somewhat different. Thecae have been found to fall into eight reasonably distinct categories as follows: (1) Outer membrane underlain by irregular vesicles. (2) Membrane underlain by close‐packed vesicles. (3) As Group 2 but with plug‐like structures attached to the inner membrane of the vesicles. (4) As Group 2 but with thin plates within the vesicles and all plates of more or less similar shape. (5) As Group 4 but plates have slight overlap. (6) Similar to Group 5 but plates are reduced in number and can be individually recognized. (7) As Group 6 but plates have elaborate flanges and their surfaces are covered by reticulations. (8) Theca mainly consisting of only two plates. It is suggested that the thecal types could from the basis for some revision of the taxonomy of the class.

Relationships between cell volume and the carbon and nitrogen content of marine photosynthetic nanoplankton

“…However, a third dinoflagellate which was C-poor, K. rotundatum, belonged to the same order as the C-rich species of Moal et al (1987). It may be that the variations in C density among dinoflagellates are related more to their thecal plate structure (Dodge and Crawford 1970). Another species, 0.…”

The occurrence of scales in the peridinian dinoflagellateHeterocapsa triquetra(Ehrenb.) Stein

“…Dujardin (Clarke & Pennick, 1972, those being of a tight spiral form, occurring on both flagella and body. Dodge & Crawford (1970) examined the thecal fine-structure of a number of armoured and unarmoured dinoflagellates using electron microscopy, but no scales were reported. Examination of Heterocapsa triquetra (Ehrenb.…”

An improved energy‐dispersive X‐ray microanalysis method for analyzing simultaneously carbon, nitrogen, oxygen, phosphorus, sulfur, and other cation and anion concentrations in single natural marine microplankton cells

“…8B), equivalent to a mass thickness of 4.8 pg cellulose µm -2 . The thickness of the dinoflagellate plates is highly variable, from 0.010-0.045 µm (e.g., Gyrodinium sp., Heterocapsa niei) to 0.150-0.600 µm (e.g., Ceratium hirundinella, Prorocentrum micans) (Dodge and Crawford 1970;Morrill and Loeblich 1983). Only a few extremely thick plates have been reported for Peridinium depressum (1.8 µm, Dodge and Crawford 1970).…”