From Lundholm et al. 2012
The cells are lanceolate in both girdle and valve view. They are 37–79 μm long and 1.5–2.8 μm wide in valve view. The valve ends are pointed in both girdle and valve view. The fibulae are not always regularly spaced and are seen using LM. The distance between the two central fibulae is larger than between the other fibulae and contains a central nodule. The densities of the fibulae and interstriae are 13–20 and 31–40 in 10 μm, respectively. The striae contain one row of more or less rounded poroids, 5–6 poroids in 1 μm. Each poroid is split in 2–6 sectors and the number may vary among valves of a clonal culture and even among the poroids within a single stria. Similarly, the size of the sectors is greatly variable. The perforation pattern of each sector is hexagonal. The mantle is structured as the valve, being 2–3 poroids high. The girdle most often comprises three bands. The valvocopula contains 37–46 band striae in 10 μm. Each band stria is 2 poroids wide and 3–6 poroids high. The next two bands contain striae with a decreasing number of poroids in the height; the second band often being 2–4 poroids high and the third band most often being 1–2 poroids high and not always 2 poroids wide. The perforation of the girdle bands is also hexagonal. An abnormal band pattern was sometimes seen where the band pattern was longitudinally interrupted. This was mainly observed in older cultures and accompanied other deformations on the valve.
This species has been reported from Japan, Washington State and from the Atlantic near Spain (Penna et al. 2007, Orive et al. 2010, Lundholm et al. 2012)
Pseudo-nitzschia hasleana is a species of pennate diatom found off the coast of Washington State. It does not produce domoic acid.
Pseudo-nitzschia hasleana is a part of the P. pseudodelicatissima complex. It resembles P. calliantha, P. mannii and P. caciantha the most but differs in having lower fibula density (Lundholm et al. 2012)
From Lundholm et al. 2012
Synapomorphy in helix IV of ITS2 of the nuclear rDNA: 5′-CTATGATCTAGGTATTGGATTATCCGA-3′ (27 bp). This sequence includes a CBC as well as a HCBC and a SNP (single nucleotide polymorphism) that differentiates P. hasleana from P. calliantha and P. mannii. A test for the uniqueness of the diagnostic signature of P. hasleana is, was confirmatory. The sequence was found to have an E-value of 2e-05 for two P. hasleana sequences in GenBank (GQ228394 and AM183801). The next five hits had E-values of 3.7 and above and were fungi, higher plants, and bacteria.