A field study was undertaken to investigate the occurrence and toxin production of species in the diatom genus Pseudo-nitzschia in Namibian waters, in the extremely productive Benguela upwelling system. From surveys conducted on the R/V Mirabilis and the R/V !Anichab, 52 strains were morphologically determined to species level, supported by nuclear ITS rDNA data. Seven species were identified; P. australis, P. decipiens, P. dolorosa, P. fraudulenta, P. plurisecta, P. pungens var. cingulata, and the new species P. bucculenta F. Gai, C. K. Hedemand, N. Lundholm & Ø. Moestrup sp. nov.

Molecular and morphological diversity of the Namibian Pseudo-nitzschia species is discussed. Most importantly, P. bucculenta is both morphologically and phylogenetically most similar to P. dolorosa differing mainly in valve width and densities of striae, poroids and band striae as well as by four hemi-compensatory base changes in the ITS2. Morphological and molecular differences among the strains of P. decipiens suggest a temperate and a warm water subdivision. The geographical and toxigenic characteristics of the identified Pseudo-nitzschia species are described and compared to previous studies. Initial tests of toxin production in all seven species revealed production of domoic acid (DA) in two species: one strain of P. australis (0.074 pg DA cell⁻¹) and two strains of P. plurisecta (0.338 pg DA cell⁻¹ and 0.385 pg DA cell⁻¹).

进行了一项野外研究，以调查在纳米比亚水域中极富生产力的Benguela上升流系统中，硅藻属假念珠菌属中硅藻属的种类及其产生的毒素。通过对R / V Mirabilis和R / V！Anichab进行的调查，在核ITS rDNA数据的支持下，从形态上确定了52个菌株的物种水平。确定了七种。芦苇，P.杜英，P.苦难，P. fraudulenta，P. plurisecta，P. pungens变种。cingulata和新种P. bucculentaF. Gai，CK Hedemand，N。Lundholm＆Ø。Moestrup sp。十一月

讨论了纳米比亚假奈瑟菌属物种的分子和形态多样性。最重要的是，P. bucculenta既是形态上和系统发生学上最相似的P.苦难主要不同在阀宽度和皮纹，poroids密度和带条纹以及由ITS2 4半代偿碱基变化。P. decipiens菌株之间的形态和分子差异表明有温带和温水细分。鉴定出的假性尼兹菌的地理和产毒特性描述并与以前的研究进行了比较。对所有七个物种的毒素产生的初步测试表明，在两个物种中均产生了杜摩酸（DA）：一株澳大利亚假单胞菌（0.074 pg DA细胞^-1）和两株毛霉假单胞菌（0.338 pg DA细胞^-1和一株）。 0.385 pg DA细胞^-1）。