Wu Xiang-Yun, Zhu Xing-Quan, Xie Ming-Quan, Li An-Xing
Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou, Guangdong Province 510275, People's Republic of China.
Mol Phylogenet Evol. 2007 Aug;44(2):530-44. doi: 10.1016/j.ympev.2007.03.025. Epub 2007 May 3.
To overcome the limited regional and taxonomic coverage in previous studies of the Ancyrocephalinae (Monogenea, Dactylogyridae), we present further findings on the molecular systematics and phylogeny of a broader selection of specimens, aiming to build a molecular phylogeny of the Ancyrocephalinae, and to assess the monophyly of each available genus, using D1-D2 domain of LSU rDNA and the combined LSU and partial sequence of SSU rDNA data sets. Our studies showed that 18 Haliotrema species were highly dispersive to form several clades with species from ten closely related genera. The host range of Euryhaliotrematoides species was not only restricted in butterfly fishes (Chaetodontidae), but widen to include the Lutjanidae. Euryhaliotrema was phylogenetically more closely related to Aliatrema than to Euryhaliotrematoides. Given that the species Haliotrema kurodai, Haliotrema spirotubiforum and Haliotrema anguiformis had a funnel-shaped base of the coiled male copulatory organ (MCO) lacking an accessory piece, and our molecular evidence, we proposed to transfer the three species to the Aliatrema as new combinations. We proposed to combine Bravohollisia and Caballeria into one genus, mainly based on molecular evidence and their similar MCO characters. Using SSU+ITS1 data set, Scutogyrus was robustly resolved as a polyphyletic group and its status should be questioned. Based on the present molecular evidence and their similar MCO characters, we proposed to combine Cichlidogyrus and Scutogyrus into one genus, Cichlidogyrus, by treating Scutogyrus as the synonym of Cichlidogyrus. Generally, the present study indicated that the vagina can make little contribution for understanding the generic-level monophyly, due to its high variability even among phylogenetically very closely related species, but it was useful for species determination. Given that phylogenetically closely related species from the same or closely related host species may have similar MCO characters but distinct haptoral characters, we consider that it is dangerous to erect a genus mainly based on different haptoral characters, particularly those separated from existing genera. The resultant phylogenetic reconstructions indicated that the radiation of some Haliotrema species has correlated with their hosts, because species from closely related fishes have correspondingly shown close relationships. Though the present study can not provide the comparison of host-parasite associations, phylogenetically closely related Haliotrema species which have similar morphological characters (both MCOs and haptors) but distinct/distantly related host species may indicate a speciation model of host-switching.
为克服以往对锚首虫亚科（单殖吸虫，指环虫科）研究中区域和分类覆盖范围有限的问题，我们展示了对更广泛标本进行分子系统发育和系统发生学研究的进一步结果，旨在构建锚首虫亚科的分子系统发育树，并利用 LSU rDNA 的 D1-D2 结构域以及 LSU 和 SSU rDNA 数据集的部分序列组合来评估每个现有属的单系性。我们的研究表明，18 种哈氏吸虫具有高度分散性，与来自十个近缘属的物种形成了几个分支。似宽盘吸虫属物种的宿主范围不仅限于蝴蝶鱼（蝴蝶鱼科），还扩大到包括笛鲷科。宽盘吸虫在系统发育上与异盘吸虫的关系比与似宽盘吸虫的关系更密切。鉴于黑氏哈氏吸虫、旋管哈氏吸虫和鳗形哈氏吸虫的卷曲雄性交配器官（MCO）基部呈漏斗形且缺少附属片，以及我们的分子证据，我们建议将这三个物种作为新组合转移到异盘吸虫属。我们建议将布氏吸虫属和卡氏吸虫属合并为一个属，主要基于分子证据及其相似的 MCO 特征。使用 SSU + ITS1 数据集，盾盘虫属被明确解析为一个多系群，其分类地位值得质疑。基于目前的分子证据及其相似的 MCO 特征，我们建议将丽鲷盘虫属和盾盘虫属合并为一个属，即丽鲷盘虫属，将盾盘虫属视为丽鲷盘虫属的同义词。总体而言，本研究表明，阴道对于理解属级别的单系性贡献不大，因为即使在系统发育关系非常密切的物种之间，其变异性也很高，但它对物种鉴定很有用。鉴于来自相同或近缘宿主物种的系统发育关系密切的物种可能具有相似的 MCO 特征但不同的钩器特征，我们认为主要基于不同的钩器特征，特别是那些与现有属分离的特征来建立一个属是危险的。由此产生的系统发育重建表明，一些哈氏吸虫物种的辐射与其宿主相关，因为来自近缘鱼类的物种相应地显示出密切的关系。尽管本研究无法提供宿主 - 寄生虫关联的比较，但具有相似形态特征（MCO 和钩器）但宿主物种不同/远缘的系统发育关系密切的哈氏吸虫物种可能表明一种宿主转换的物种形成模式。
