Pseudo-nitzschia caciantha

P. caciantha is a chain-forming pennate diatom found in tropical waters. It is not a known domoic acid producer. P. caciantha has not been reported in a large monospecific bloom.

From Lundholm et al. 2003: Overlapping cells in colonies. Cells lanceolate with a tendency to being slightly asymmetrical in apical axis, 2.7-3.5 microns wide, 53-75 microns long. Raphe eccentric, divided in the middle by a central nodule. Fifteen to 19 fibulae in 10 microns, interstriae 28-31 in 10 microns. Striae perforated by one row of poroids, 3.5-5 poroids in 1 micron. Hymen of poroids usually divided into four to five sectors. Valve mantle structured as valve face, 1-2 poroids high. Valvocopula contains 33-38 striae in 10 microns; each stria is two poroids wide and 3-5 poroids high. Striae of the second copula two poroids wide and two poroids high.

Pseudo-nitzschia caciantha has thus far only been reported in tropical waters.

P. caciantha form the step-chains characteristic of the genus. Cells are long and thin and slightly asymmetrical in valve view. Each stria contains one row of nearly square poroids with hymen perforations in a hexagonal pattern.

Analysis of ITS and ML shows that P. caciantha is most closely related to P. subpacifica and P. calliantha (Lundholm et al. 2002).

Domoic acid was detected, but not quantified, in cultures of P. cf. caciantha. The presence of DA was detected by HPLC and LC-MS/MS