The genus Alexandrium comprises some of the most potentially toxic marine algae. A new toxic species of Alexandrium, A. fragae sp. nov., was found in Guanabara Bay, Rio de Janeiro, southern Brazil. The new species produces GTX2&3 and STX. The cell morphology of A. fragae resembles A. minutum in many characters, including the small size; the rounded-elliptical shape; and the shapes of the apical pore complex (APC), first apical plate (1′), sixth precingular plate (6″), and anterior and posterior sulcal plates (s.a. and s.p.). The main diagnostic characters of A. fragae are the ornamentation pattern, smooth epitheca and reticulated hypotheca, all of which were present in both natural populations and cultures. Phylogenies inferred from the ITS, LSU, and SSU rDNA of A. fragae showed that A. fragae clustered in a well-supported clade, distinct from other Alexandrium species. Morphology and molecular analyses based on ITS and LSU rDNA indicated that A. fragae strains and Alexandrium sp. from Japan (D163C5, D164C6) are a single species. Our findings suggest that the Alexandrium morphotype with a smooth epitheca and reticulated hypotheca, previously identified as A. minutum in different geographic regions, may corresponds to A. fragae.

亚历山大藻属包括一些最具潜在毒性的海藻。亚历山大藻的一种新有毒种，A。fragae sp.。11月在巴西南部里约热内卢的瓜纳巴拉港被发现。新物种生产GTX2＆3和STX。Fra。a。fragae的细胞形态在许多特征上都类似于A. minutum，包括小号。圆椭圆形；以及顶孔复合物（APC），第一根顶板（1'），第六前龈板（6''）以及前，后沟板（sa和sp）的形状。草莓曲霉的主要诊断特征是装饰图案，光滑的上皮和网状的假说，它们都存在于自然种群和文化中。从A. fragae的ITS，LSU和SSU rDNA推导的系统发育系统表明，A。fragae聚集在一个支撑良好的进化枝中，与其他亚历山大属物种不同。基于ITS和LSU rDNA的形态和分子分析表明，A. fragae菌株和Alexandrium sp。来自日本的（D163C5，D164C6）是单个物种。我们的发现表明，具有平滑上皮和网状假说的亚历山大形态，先前在不同地理区域被鉴定为细小曲霉。A.fragae。