Razzolini Emanuel, Murari Anelise Levay, Baldisserotto Bernardo, Boeger Walter A
Laboratório de Ecologia Molecular e Parasitologia Evolutiva, Dept. de Zoologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
Laboratório de Fisiologia de Peixes, Dept. de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
Syst Parasitol. 2019 Jun;96(4-5):407-415. doi: 10.1007/s11230-019-09858-8. Epub 2019 May 13.
Species of Monogenoidea (Platyhelminthes) are in its majority ectoparasites of marine and freshwater fishes. Many species of the group can promote great economic losses to fish production systems worldwide. The present study describes a new species, Gyrodactylus lilianae n. sp., from the body surface, fins and barbels of a captive South American catfish, Rhamdia quelen (Quoy & Gaimard) (Siluriformes: Heptapteridae) from southern Brazil. The new species is morphologically similar to Neotropical species of Gyrodactylus von Nordmann, 1832 from Siluriformes from which it differs most conspicuously by the morphology of the hook with a pronounced convex heel, somewhat depressed, slightly pointed toe, and a small distal bulb. The identity of the new species is also strongly supported by phylogenetic analysis based on cytochrome c oxidase subunit 2 mitochondrial gene (cox2) sequences and the rDNA fragment ITS1-5.8-ITS2. Infections with the new species in captive R. quelen juveniles were considered the main causative agent of observed mortalities. Tissue damage caused by G. lilianae n. sp. apparently facilitated the occurrence of secondary infections by protists (Ichthyophthirius multifiliis) and bacteria (Aeromonas hydrophila).
单殖吸虫纲（扁形动物门）的物种大多是海洋和淡水鱼类的体外寄生虫。该类群的许多物种会给全球的鱼类养殖系统造成巨大经济损失。本研究描述了一种新物种，即来自巴西南部人工养殖的南美鲶鱼——奎氏溪鲇（Rhamdia quelen (Quoy & Gaimard)，鲇形目：项鳍鲇科）体表、鳍和触须上的莉莉安娜三代虫（Gyrodactylus lilianae n. sp.）。该新物种在形态上与来自鲇形目的1832年命名的新热带三代虫属（Gyrodactylus von Nordmann）物种相似，与之最显著的区别在于其钩的形态，有明显凸起的钩跟，稍凹陷，趾部略尖，还有一个小的远端球状物。基于细胞色素c氧化酶亚基2线粒体基因（cox2）序列和核糖体DNA片段ITS1 - 5.8 - ITS2的系统发育分析也有力支持了该新物种的身份。在人工养殖的奎氏溪鲇幼鱼中，感染该新物种被认为是观察到的死亡现象的主要致病因素。莉莉安娜三代虫造成的组织损伤显然促使了原生生物（多子小瓜虫）和细菌（嗜水气单胞菌）继发感染的发生。
