Franceschini L, Acosta A A, Zago A C, Müller M I, da Silva R J
Department of Parasitology, São Paulo State University (UNESP), Institute of Biosciences, Rua Professor Doutor Antônio Celso Wagner Zanin, 250, Botucatu, São Paulo CEP 18618-689, Brazil.
Water Research Group, Unit for Environmental Sciences and Management, Potchefstroom Campus, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa.
J Helminthol. 2020 Feb 20;94:e126. doi: 10.1017/S0022149X20000097.
This study describes two new species, Trinigyrus anthus n. sp. and Trinigyrus carvalhoi n. sp., from gills of Hypostomus spp. from the Upper Paraná River basin, Brazil. Trinigyrus peregrinus is redescribed based on examination of its holotype, paratypes and new material of specimens parasitizing Pterygoplichthys ambrosettii, also from the Upper Paraná River basin, Brazil. New morphological features were included in the diagnosis of the genus, such as the presence of a sclerotized border on the anchor base, and a weakly sclerotized fringe on the base of the male copulatory organ (MCO). Trinigyrus anthus n. sp. differs from other congeners by the shape of the MCO, presenting an enlarged base with sclerotized fringes resembling flower petals. Trinigyrus carvalhoi n. sp. and T. peregrinus are similar but can be differentiated from each other mainly by the sclerotization of the vagina (absent in the new species), and the morphology of the MCO (C-shaped versus one counterclockwise circle, respectively). For the first time, gene sequences of Trinigyrus spp. from Brazil were obtained (partial ribosomal 28S and mitochondrial cytochrome c oxidase I (mtCOI)). The genetic divergences among the new species and T. peregrinus varied from 2 to 3% (6‒18 pb) based on sequences of 28S ribosomal DNA (rDNA), and 6-7% (83‒92 pb) using mtCOI. Phylogenetic analyses based on partial 28S rDNA revealed that Trinigyrus, Heteropriapulus and Unilatus formed a monophyletic and well-supported clade of monogeneans from Neotropical freshwater loricariids, suggesting a closer relationship among these dactylogyrids and their hosts.
本研究描述了来自巴西巴拉那河上游流域下口鲶属鱼类鳃部的两个新物种，即繁花三齿铗钩虫（Trinigyrus anthus n. sp.）和卡氏三齿铗钩虫（Trinigyrus carvalhoi n. sp.）。基于对其正模标本、副模标本以及同样来自巴西巴拉那河上游流域寄生于安氏翼甲鲶（Pterygoplichthys ambrosettii）的新标本材料的检查，对漂泊三齿铗钩虫（Trinigyrus peregrinus）进行了重新描述。该属的诊断纳入了新的形态特征，如锚基上存在硬化边缘，以及雄性交配器官（MCO）基部有弱硬化边缘。繁花三齿铗钩虫新物种与其他同属物种的区别在于MCO的形状，其基部扩大，有类似花瓣的硬化边缘。卡氏三齿铗钩虫新物种和漂泊三齿铗钩虫相似，但主要可通过阴道的硬化情况（新物种中不存在）以及MCO的形态（分别为C形和逆时针一圈）相互区分。首次获得了来自巴西的三齿铗钩虫属物种的基因序列（部分核糖体28S和线粒体细胞色素c氧化酶I（mtCOI））。基于28S核糖体DNA（rDNA）序列，新物种与漂泊三齿铗钩虫之间的遗传差异为2%至3%（6 - 18个碱基对），使用mtCOI时为6% - 7%（83 - 92个碱基对）。基于部分28S rDNA的系统发育分析表明，三齿铗钩虫属、异 Priapulus属和单带虫属形成了一个来自新热带淡水甲鲶科的单系且支持良好的单殖吸虫类分支，表明这些指环虫类与其宿主之间关系更为密切。
