Ciguatera fish poisoning (CFP) is a human illness caused via consumption of seafood contaminated with neurotoxins produced by some species from the epiphytic dinoflagellate genus Gambierdiscus. In this study, we describe two new species of Gambierdiscus isolated from Heron Island in the Southern Great Barrier Reef, Queensland, Australia. These new species were analysed using light microscopy, scanning electron microscopy, and phylogenetic analyses of nuclear encoded ribosomal ITS, SSU as well as D1-D3 and D8-D10 of the LSU gene regions. Gambierdiscus lewisii sp. nov. (Po, 3′, 0a, 7″, 6c,? s, 5‴, 0p, 2′‴) is distinguished by its strong reticulate-foveate ornamentation and is genetically distinct from its sister species, G. pacificus. Gambierdiscus holmesii sp. nov. (Po, 3′, 0a, 7″, 6c, 6s?, 5‴, 0p, 2′‴) is morphologically distinct from the genetically similar species G. silvae because of a strongly ventrally displaced apical pore complex and a characteristic fold at the anterior edge of the sulcus. Both G. lewisii and G. holmesii produce putative Maitotoxin-(44-Methylgambierone) and compounds which show ciguatoxin and maitotoxin-like activities. Identification of two new Gambierdiscus species will enable us to more accurately assess the risk of CFP in Australia and internationally.

Ciguatera鱼中毒（CFP）是一种人类疾病，是由于食用被附生的鞭鞭藻属Gambierdiscus某些物种产生的神经毒素污染的海鲜所致。在这项研究中，我们描述了从澳大利亚昆士兰州南部大堡礁的苍鹭岛中分离出的两种冈比亚新物种。使用光学显微镜，扫描电子显微镜以及核编码核糖体ITS，SSU以及LSU基因区域的D1-D3和D8-D10的系统发育分析，对这些新物种进行了分析。Gambierdiscus lewisii sp。十一月 （Po，3'，0a，7''，6c，？s，5‴，0p，2'‴）的特征是其强烈的网状叶状纹饰，并且在遗传上不同于其姊妹物种G. pacificus。Gambierdiscus holmesii sp。十一月 （Po，3'，0a，7''，6c，6s ?, 5‴，0p，2'‴）在形态上与遗传相似的种G. silvae不同，这是由于强烈的腹侧移位的顶孔复合物和在沟的前缘。既G. lewisii和G. holmesii产生推定Maitotoxin-（44-Methylgambierone）并示出雪卡毒素和刺尾鱼毒素样活性的化合物。鉴定两个新的冈比亚双歧杆菌物种将使我们能够更准确地评估澳大利亚和国际上CFP的风险。