Fragilariopsis oceanica (Cleve) Hasle 1965 competes with F. reginae-jahniae for our attention. Both of them are almost always present in the samples from both Bering and Chukchi seas, but F. oceanica is usually more numerous.
It's smaller, up to 43 um, and, being more elliptical and less silicified, looks cosier. The valves can be almost curcular, elliptical, lanceolate or even more or less linear, but they are never as strict and linear as F. reginae-jahniae and have protruded rather than rounded apices. F. oceanica is 9.2-42.5 um long and 4.6-8.2 um wide (shorter and wider relative to the length than F. reginae-jahniae) with 12-18 interstriae and 12-16 fibulae in 10 um.
And of course, since it's one of the most abundant diatoms in the Bering Sea, I have only four LM pictures of it.
(Photo by Dr. Beth Caissie)
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