Heterocapsa circularisquama is small thecate dinoflagellate which belongs to Peridiniales. Dr. Horiguchi of Hokkaido University describes H. circularisquama as a new species. H. circularisquama looks like typical spindle shape of dinoflagellates. It has thin plates, and yellow brownish chromatophores. Cells are 18-30μm in length, and 12-22μm in width. The cell has a deep girdle, comparatively shallow sulcus, and sharp apex. Typical hypnozygote (cyst) is not known but vegitative cells of H. circularisquama transform their cells to temporary cyst when the environmental conditions became unsatisfactory. For the species identification, body scale morphology should be confirmed.
Numerous endosymbiotoc bacteria were found in cytoplasma and autolysosome of almost H. circularisquama cells.

Photomicrograph of Heterocapsa circularisquama
 

[Back]