A = Chain at two focal planes; B = Valve view. (A&B DIC); C = Frustule, valve view (arrowheads=strutted processes, arrow=labiate process. (PC)
Life-form: Solitary or cells united in chains
Distinctive features: Loose chains, one large labiate process, many strutted processes
Similar species: Porosira pentaportula
Distribution: In cold water in the northern and southern hemispheres
Hasle, G. R. 1973a. Some marine plankton genera of the diatom family Thalassiosiraceae. Beiheft zur Nova Hedwigia. 45: 1-49.
Hasle, G. R. & Syvertsen, E. E. 1996. Marine diatoms. In: Tomas, C. R. (ed.) Identifying marine diatoms and dinoflagellates. Academic Press, Inc., San Diego, p. 5-385.
Takano, H. 1990. Diatoms. In "Red tide organisms in Japan-An illustrated taxonomic guide". (Y. Fukuyo, H. Takano, M. Chihara & K. Matsuoka eds) . Uchida Rokakuho, Tokyo, p. 162-331.