中文摘要：

佩氏拟多甲藻Peridiniopsis penardii（Lemmermann）Bourrelly是1种淡水甲藻，可以形成水华，分布在意大利，美国，日本和中国。在2009年春季，厦门九龙江北溪发生水华。分离出来的细胞在培养条件下形成休眠包囊，细胞经光镜，扫描电镜（SEM），以及核糖体rDNA18S序列分析，证实引起水华的是佩氏拟多甲藻。包囊椭圆形，直径大约28μm。细胞上鞘呈圆锥形，下鞘圆形或圆锥形，长23～36μm，宽23～31μm。甲板方程式为Po，x，4’，0a，6”，5C（或t＋4c），5s，5”’，2””。佩氏拟多甲藻具有2个细胞核，其中一个为自身细胞核，另外一个为共生的硅藻细胞核。我们对佩氏拟多甲藻和共生硅藻的18s进行了测定并构建了基因树，他们的系统发育位置和形态学分类相吻合。

英文摘要：

Peridiniopsis penardii （Lemmermann） Bourrelly is a bloom forming freshwater dinoflagellate which is recorded world widely, in Italy, America, Japan and China. The P. penardii vegative cell was isolated from blooming water in the Jiulongjiang Estuary in spring, 2009, and then it generated resting cysts spontaneously in the cultures. The vegative cell comprises a conical epitheca, and a round- ed or slightly conical hypotheca, with a dimension of 23~36 t~m wide and 23-31 μm long. The cyst is oval with a diameter of 28 μm. The plate formula of P. penardii vegative cell is Po, x, 4＇, 0a, 6＇ ＇, 5c （or t＋4c）, 5s, 5＇＇ ＇, 2＇＇＇. The P. penardii cell usually possesses an endosymbiotic diatom. Molecular phylogenetic analyses of small subunit ribosomal （SSU） rRNA of both P. penardii and the endosymbiotic diatom agree with the morphological taxonomy and its endosymbiotic relationship.