Research Unit for Palaeontology, Ghent University, Krijgslaan 281 s8, 9000 Ghent, Belgium.
Oregon State University, Department of Botany and Plant Pathology, College of Agricultural Sciences, 2082 Cordley Hall, Corvallis, OR 97331-2902, USA.
Harmful Algae. 2018 Jan;71:57-77. doi: 10.1016/j.hal.2017.12.003. Epub 2017 Dec 16.
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.
来自索尔顿海的一种甲藻的菌株，先前被鉴定为 Protoceratium reticulatum 和产生 yessotoxin，已经在形态学和遗传学上进行了重新检查，并建立了 Pentaplacodinium saltonense n. gen. et sp. 以容纳这个物种。Pentaplacodinium saltonense 与 Protoceratium reticulatum (Claparède et Lachmann 1859) Bütschli 1885 在前置板的数量 (五个对六个)、环带移位 (两个宽度对一个) 和明显的囊泡形态上有所不同。孵化实验 (出囊和入囊) 表明，Pentaplacodinium saltonense 的休眠囊泡在形态上与囊泡定义的物种 Operculodinium israelianum (Rossignol, 1962) Wall (1967) 和 O. psilatum Wall (1967) 最为相似。来自全球各地的比较材料收集 (包括 Protoceratium reticulatum 和 Ceratocorys 属) 和单细胞 PCR 用于阐明分子系统发育。从 LSU(三个新序列)、SSU(12 个新序列)和基因间 ITS 1-2(14 个新序列)获得了可变区。这些表明，Pentaplacodinium saltonense 和 Protoceratium reticulatum 形成两个不同的分支。Pentaplacodinium saltonense 与来自马来西亚的几个未识别菌株一起形成一个单系分支。来自地中海的三种 Ceratocorys 物种 (C. armata、C. gourreti、C. horrida) 和来自马来西亚的几个其他未识别菌株的 LSU 和 SSU rDNA 序列形成了一个支持良好的姊妹分支。来自夏威夷的一个未识别菌株的独特系统发育位置也得到了记录，并需要进一步研究。此外，基于 V9 SSU 拓扑结构 (自举值>80%)，最初由 Reinecke (1967) 描述为 Gonyaulax grindleyi 的来自 Elands Bay (南非) 的标本与 Protoceratium reticulatum 聚类。Pentaplacodinium saltonense 的已知范围为热带到亚热带，其囊泡被记录为上新世沉积物中的化石。似乎 Protoceratium reticulatum 和 Pentaplacodinium saltonense 栖息在不同的小生境中：这些甲藻的运动阶段尚未在同一浮游样本中发现。
