Pseudo-nitzschia arctica
No picture so far.
Forms stepped chains. Two chloroplasts, one in each end, are seen in all cells. The cells are lanceolate in valve view, linear in girdle view. The valves have an eccentric raphe with a central nodule, parallel interstriae and almost twice as many interstriae than fibulae. One row of rounded poroids, and each poroid has 1-5 sectors. A cingulum with three bands.
Morphometrics; Apical axis (heteropolar) 26-67 µm, transapical axis 1.6-2.5 µm, 17-24 fibulae and 33-39 interstriae in 10 µm. Poroid density 4-6 in 1 µm. First girdle band with 41-48 band striae in 10 µm, each being 1-3 poroids high and 2 poroids wide.
Is similar to several species in the pseudodelicatissima-complex, particularly P. fryxelliana. For correct identification detailed EM or molecular data are needed
Percopo I, Ruggiero MV, Balzano S, Gourvil P, Lundholm N, Siano R, Tammilehto A, Vaulot D, Sarno D. 2016. Pseudo-nitzschia arctica sp. nov., a new cold-water cryptic Pseudo-nitzschia species within the P. pseudodelicatissima complex. Journal of Phycology, 152:184-199.
Has not been recorded outside the Arctic.