Strains of a dinoflagellate from the Salton Sea, previously identified as Protoceratium reticulatum and yessotoxin producing, have been reexamined morphologically and genetically and Pentaplacodinium saltonense n. gen. et sp. is erected to accommodate this species. Pentaplacodinium saltonense differs from Protoceratium reticulatum (Claparède et Lachmann 1859) Bütschli 1885 in the number of precingular plates (five vs. six), cingular displacement (two widths vs. one), and distinct cyst morphology. Incubation experiments (excystment and encystment) show that the resting cyst of Pentaplacodinium saltonense is morphologically most similar to the cyst-defined species Operculodinium israelianum (Rossignol, 1962) Wall (1967) and O. psilatum Wall (1967). Collections of comparative material from around the globe (including Protoceratium reticulatum and the genus Ceratocorys) and single cell PCR were used to clarify molecular phylogenies. Variable regions in the LSU (three new sequences), SSU (12 new sequences) and intergenic ITS 1–2 (14 new sequences) were obtained. These show that Pentaplacodinium saltonense and Protoceratium reticulatum form two distinct clades. Pentaplacodinium saltonense forms a monophyletic clade with several unidentified strains from Malaysia. LSU and SSU rDNA sequences of three species of Ceratocorys (C. armata, C. gourreti, C. horrida) from the Mediterranean and several other unidentified strains from Malaysia form a well-supported sister clade. The unique phylogenetic position of an unidentified strain from Hawaii is also documented and requires further examination. In addition, based on the V9 SSU topology (bootstrap values >80%), specimens from Elands Bay (South Africa), originally described as Gonyaulax grindleyi by Reinecke (1967), cluster with Protoceratium reticulatum. The known range of Pentaplacodinium saltonense is tropical to subtropical, and its cyst is recorded as a fossil in upper Cenozoic sediments. Protoceratium reticulatum and Pentaplacodinium saltonense seem to inhabit different niches: motile stages of these dinoflagellates have not been found in the same plankton sample.

来自索尔顿海的鞭毛藻的菌株，以前被鉴定为网纹原杆菌和产生毒素，已经在形态和遗传学上重新鉴定，并重新鉴定了Pentaplacodinium saltonense n。gen。等 竖立以容纳该物种。Pentaplacodinium saltonense与Protoceratium reticulatum（Claparèdeet Lachmann 1859）Bütschli1885的不同之处在于前规板的数量（五个与六个），扣带移位（两个宽度与一个）和明显的囊肿形态。孵化实验（去囊化和囊化）表明，Pentaplacodinium saltonense的静止囊肿在形态上与囊肿定义的以色列古猿Operculodinium israelianum最为相似（Rossignol，1962）Wall（1967）和O. psilatum Wall（1967）。收集了来自全球的比较材料（包括Protoceratium reticulatum和Ceratocorys属）和单细胞PCR来阐明分子系统发育。获得了LSU（三个新序列），SSU（12个新序列）和基因间ITS 1–2（14个新序列）中的可变区。这些表明五齿pla和网纹原藻形成两个不同的进化枝。Pentaplacodinium saltonense与来自马来西亚的数种不明菌株形成单系进化枝。三个物种的LSU和SSU rDNA序列Ceratocorys（来自地中海的C. armata，C。gourreti和C. horrida以及来自马来西亚的其他几种不明菌株形成了一个得到良好支持的姐妹进化枝。来自夏威夷的一株未鉴定菌株的独特系统发生位置也有记载，需要进一步检查。另外，基于V9 SSU拓扑（引导值> 80％），来自Relands（最初由Reinecke（1967年）描述为Gonyaulax grindleyi）的伊兰兹湾（南非）的标本与网状Protoceratium一起聚集。Pentaplacodinium saltonense的已知范围是热带到亚热带，其囊肿被记录为新生代上层沉积物中的化石。网状原角藻和Pentaplacodinium saltonense 似乎栖息于不同的生态位：在同一浮游生物样本中未发现这些鞭毛鞭毛虫的活动阶段。