A = Vegetative cells (DIC); B & C = Resting spores (DIC); D = Valve with strutted processes and labiate process (=arrow) (PC)
Life-form: Cells in loose chains
Size: Diameter 12-32 µm
Resting spore: +
Note:
Distinctive features: A central cluster of strutted processes, one ring of strutted processes, and one labiate process within this ring. Resting spore.
Similar species: Thalassiosira antarctica T. hyalina T. gravida
Distribution: Arctic - subarctic, Skagerrak
Literature:
Gaarder, K. R. 1938. Phytoplankton studies from the Tromsø
district 1930-31. Tromsø Museums Årshefter,
Naturhistorisk avd. nr. 11. Vol. 55 (1932) nr.1.
Heimdal, B. R. 1971. Vegetative cells and resting spores of Thalassiosira constricta Gaarder (Bacillariophyceae). Norw. J. Bot. 18, 153-159.
Heimdal, B. R. 1974. Further observations on the resting spores of Thalassiosira constricta Gaarder (Bacillariophyceae). Norw. J. Bot. 21, 303-307.