The Diplozoidae are monogenean parasites of mainly cyprinoid fishes with a unique life cycle, whereby two larvae undergo anastomosis and fuse into a single cross-shaped specimen. Paradiplozoon is the most species rich and widespread genus of the family, with a distribution range covering Eurasia and Africa; however, some areas remain underexplored and their diplozoid fauna is uncertain. In the present study, the Paradiplozoon diversity was investigated in the peri-Mediterranean region, which has the highest levels of cyprinoid diversity and endemism in Europe. A total of 36 endemic cyprinoid species were sampled from sites in north-west Africa and the southern European peninsulas and investigated for the presence of diplozoid parasites. Of five Paradiplozoon species collected, three were identified as new to science: Paradiplozoon moroccoensis n. sp. from the Moroccan endemic Luciobarbus lepineyi; Paradiplozoon ibericus n. sp. from Iberian endemic cyprinids and leuciscids and Paradiplozoon helleni n. sp. from the Greek endemic Scardinius acarnicus and Tropidophoxinellus hellenicus (descriptions provided herein). In addition, new host records for P. homoion and P. megan are presented, with the former being most prevalent in the investigated region. Phylogenetic analysis supported paraphyly of the genus Paradiplozoon, and suggests the need for a careful taxonomic re-evaluation of this genus. Furthermore, the results showed that endemic Paradiplozoon of the peri-Mediterranean do not form a monophyletic group, suggesting multiple origins of this parasite groups in different peri-Mediterranean regions.

双龙科是主要为类环礁鱼类的单系寄生虫，具有独特的生命周期，其中两个幼虫进行吻合并融合成单个十字形标本。准双足动物是该家族中物种最多，分布最广的属，分布范围覆盖欧亚大陆和非洲。但是，有些地区仍未开发，其双线类动物区系尚不确定。在本研究中，在地中海沿岸地区调查了副双足动物的多样性，该地区在欧洲具有最高水平的赛璐in多样性和地方性。从西北非洲和欧洲南部半岛的地点总共采样了36种特有的类环孢素物种，并调查了双孢类寄生虫的存在。五个副翼龙收集到的物种中，有3种被确定为对科学不熟悉的新物种：Paradiplozoon moroccoensis n。sp。来自摩洛哥的地方性Luciobarbus lepineyi ; Paradiplozoon ibericus ñ。sp。来自伊比利亚特有的鲤科鱼类和leuciscids以及副产双孢霉属。sp。来自希腊特有的Scardinius acarnicus和Tropidophoxinellus hellenicus（本文提供描述）。此外，还提供了新的关于P. homoion和P. megan的宿主记录，其中前者在研究区域中最为普遍。系统发育分析支持副双亲属的副生，并建议对该类进行仔细的分类学重新评估。此外，结果表明，地方性Paradiplozoon围地中海不形成单系类群，表明在不同的周围区域地中海这种寄生虫组的多个来源。