Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia.
Senckenberg Research Institute, Senckenberg am Meer, German Center for Marine Biodiversity Research (DZMB), Südstrand 44, D-26382 Wilhelmshaven, Germany.
Harmful Algae. 2016 Dec;60:116-130. doi: 10.1016/j.hal.2016.11.004. Epub 2016 Nov 18.
Cryptic and pseudo-cryptic species are common amongst marine phytoplankton, and may cause misleading inferences of ecological and physiological data of plankton community studies. Deciphering the diversity and distribution of species of the benthic dinoflagellate Ostreopsis is one example, as there are many morphologically indistinct clades that differ greatly genetically and toxicologically from one another. In this study, a new species, Ostreopsis rhodesae from the southern Great Barrier Reef was described. While it initially appeared to be highly similar to several other Ostreopsis species, we found O. rhodesae can be distinguished based on the relative size of the second apical plate (2'), which is twice as long as the APC plate, and separates the third apical (3') from the third precingular (3'') plate. Phylogenetic trees based on the SSU, ITS/5.8S and D1-D2 and D8-D10 regions of the LSU rRNA were well supported, and showed a clear difference to other Ostreopsis clades. Compensatory base changes (CBCs) were identified in helices of the ITS2 between O. rhodesae and O. cf. ovata and O. cf. siamensis, which were also present in the same habitat. Fish gill cell lines were toxic to O. rhodesae, cell extracts but no palytoxin-like analogues were found in them. The findings highlight a case of pseudo-cryptic speciation, found in sympatry with closely related and morphologically similar species, but biologically and functionally distinct.
海洋浮游植物中普遍存在隐种和拟隐种，这可能导致对浮游生物群落研究的生态和生理数据产生误导性推断。底栖甲藻夜光藻的多样性和分布就是一个例子，因为有许多形态上无法区分的分支在遗传和毒理学上彼此差异很大。在这项研究中，描述了来自大堡礁南部的一个新种——罗氏夜光藻。虽然它最初似乎与其他几种夜光藻非常相似，但我们发现罗氏夜光藻可以根据第二顶片（2'）的相对大小来区分，2'的长度是 APC 板的两倍，将第三顶片（3'）与第三前幅片（3'')分开。基于 SSU、ITS/5.8S 和 LSU rRNA 的 D1-D2 和 D8-D10 区域构建的系统发育树得到了很好的支持，与其他夜光藻分支明显不同。在罗氏夜光藻和 O. cf. ovata 和 O. cf. siamensis 的 ITS2 螺旋中发现了补偿碱基变化（CBCs），这些变化也存在于同一栖息地。罗氏夜光藻对鱼类鳃细胞系有毒，但在这些细胞系中未发现鱼精细胞毒素类似物。这些发现强调了一种拟隐种的形成，它与亲缘关系密切且形态相似的物种同域分布，但在生物学和功能上是不同的。
