Boeger W A, Kritsky D C
Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, Brazil.
Int J Parasitol. 1997 Dec;27(12):1495-511. doi: 10.1016/s0020-7519(97)00140-9.
A revised hypothesis for the phylogeny of the Subclass Polyonchoinea (Monogenoidea) was constructed employing phylogenetic systematics. The Acanthocotylidae (formerly of the Order Capsalidea) is transferred to the Order Gyrodactylidea based on this analysis. The new phylogeny is used to determine coevolutionary relationships of the familial taxa of Monogenoidea with their hosts. The coevolutionary analysis suggests that the Monogenoidea apparently underwent sympatric speciation or dispersal while parasitic on ancestral Gnathostomata, resulting in two primary clades: the Polyonchoinea and the Oligonchoinea + Polystomatoinea. The two parasite clades apparently cospeciated independently with divergence of the Chondrichthyes and Osteichthyes. In the Polyonchoinea, the clade associated with Chondrichthyes experienced primary extinction within the Holocephala, but coevolved into the Loimoidae and Monocotylidae in the Galeomorphii and Squalea (Elasmobranchii), respectively. Within the Osteichthyes, polyonchoineans experienced primary extinction with the divergence of Sarcopterygii, Polypteriformes and Acipenseriformes. They demonstrate primary dispersal from the Neopterygii into the Squalea (as Amphibdellatinea), Actinistia (as Neodactylodiscinea) and Urodela (as Lagarocotylidea). Secondary dispersals of polyonchoineans occurred in the Gyrodactylidae to the Polypteriformes, Urodela and Anura; in the Acanthocotylidae to the Myxinoidea and Squalea; in the Capsalidae to the Acipenseriformes and Elasmobranchii; and in the Monocotylidae to the Holocephala. The Oligonchoinea and Polystomatoinea developed upon divergence of the Chondrichthyes and Osteichthyes. Oligonchoineans cospeciated within the Chondrichthyes, with the Chimaericolidea developing within the Holocephala and the ancestor of the Diclybothriidea + Mazocraeidea within the Elasmobranchii. Two cases of primary dispersal occurred within this clade: the Diclybothriidae to the Acipenseriformes and the ancestor of mazocraeidean families to the Neopterygii (both Osteichthyes). Secondary dispersal within the Oligonchoinea includes host switching of the common ancestor of Callorhynchocotyle (Hexabothriidae) to the Holocephala. Polystomatoineans coevolved within the Osteichthyes, but experienced primary extinctions in the Actinopterygii, Actinistia, Dipnoi and Amniota. Coevolution of the Sphyranuridae and Polystomatidae occurred with divergence of the Urodela and Anura, respectively. Secondary dispersal of Polystomatids to the Urodela, Dipnoi and Amniota is suggested. A preliminary phylogenetic analysis of the Polystomatoinea suggests that primary extinction with secondary dispersal of polystomatids to the Dipnoi may not be necessary to explain extant parasite distributions, since Concinnocotyla (Concinnocotylinae) appears to represent the sister taxon of the remaining Polystomatidae + Sphyranuridae.
运用系统发育系统学构建了多钩亚纲（单殖吸虫纲）系统发育的修正假说。基于此分析，棘口科（原属锚首虫目）被转移至三代虫目。新的系统发育关系用于确定单殖吸虫纲各家族分类单元与其宿主的协同进化关系。协同进化分析表明，单殖吸虫纲在寄生于原始的颚口纲动物时显然经历了同域物种形成或扩散，从而产生了两个主要分支：多钩亚纲和寡钩亚纲 + 多盘亚纲。这两个寄生虫分支显然随着软骨鱼纲和硬骨鱼纲的分化而独立地共同物种形成。在多钩亚纲中，与软骨鱼纲相关的分支在全头亚纲内经历了一次主要灭绝事件，但分别在板鳃亚纲的真鲨目和角鲨目（软骨鱼纲）中共同进化为蛭形科和单殖科。在硬骨鱼纲内，多钩亚纲动物随着肉鳍鱼纲、多鳍鱼目和鲟形目的分化而经历了一次主要灭绝事件。它们显示出从新鳍亚纲向角鲨目（如两栖盘虫亚纲）、腔棘鱼纲（如新指盘虫亚纲）和有尾目（如拉加盘虫科）的一次主要扩散。多钩亚纲动物的二次扩散发生在三代虫科向多鳍鱼目、有尾目和无尾目的扩散；棘口科向盲鳗亚纲和角鲨目的扩散；锚首科向鲟形目和板鳃亚纲的扩散；以及单殖科向全头亚纲的扩散。寡钩亚纲和多盘亚纲在软骨鱼纲和硬骨鱼纲分化后发展起来。寡钩亚纲动物在软骨鱼纲内共同物种形成，其中全头亚纲内形成了奇头虫科，板鳃亚纲内形成了双盘虫科 + 指环虫科的祖先。该分支内发生了两次主要扩散事件：双盘虫科向鲟形目的扩散以及指环虫科各家族的祖先向新鳍亚纲（均为硬骨鱼纲）的扩散。寡钩亚纲内的二次扩散包括 Callorhynchocotyle（六钩科）的共同祖先向全头亚纲的宿主转换。多盘亚纲动物在硬骨鱼纲内共同进化，但在辐鳍鱼纲、腔棘鱼纲、肺鱼目和羊膜动物中经历了一次主要灭绝事件。蛭科和多盘科分别随着有尾目和无尾目的分化而共同进化。推测多盘科向有尾目、肺鱼目和羊膜动物的二次扩散。对多盘亚纲的初步系统发育分析表明，对于现存寄生虫分布的解释，多盘科向肺鱼目的主要灭绝及二次扩散可能并非必要，因为 Concinnocotyla（Concinnocotylinae）似乎代表了其余多盘科 + 蛭科的姐妹分类单元。
