A new species of Creptotrematina Yamaguti, 1954 was collected from characid fishes, Astyanax fasciatus (Cuvier, 1819) and Astyanax lacustris Lucerna & Soares, 2016 from the Batalha River in the State of Sao Paulo, Brazil. The new species most closely resembles Creptotrematina aguirrepequenoi, but differs by the elongated shape of vitelline follicles, the extension of these follicles in the posterior end of body and the fact that they are not confluent. The morphological differences were confirmed through molecular data. Three specimens were sequenced, and molecular analyses were based on the internal transcribed spacers 2 and D1–D3 domains of the 28S ribosomal RNA gene. The obtained topologies showed the new species as a sister taxon of C. aguirrepequenoi, a species originally described from Astyanax mexicanus in Mexico, and later found in Astyanax aeneus in Costa Rica. Isolates of the new species are reciprocally monophyletic, and genetic distance values are similar to those observed in other species pairs within Allocreadiidae. These findings corroborate that the genus Creptotrematina is mostly a parasite of characids, and widely extended across the Americas, with representative species occurring between Argentina and northern Mexico.

中文翻译：

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巴西软鳍鱼的一新种Creptotrematina (Trematoda: Allocreadiidae): 形态和分子数据

一种新的物种甲壳虫Yamaguti，1954 年采集自 characid 鱼，凤尾鱼（居维叶，1819）和凤梨Lucerna & Soares，2016 年，来自巴西圣保罗州的巴塔利亚河。新物种最相似鲢鱼, 但不同之处在于卵泡的细长形状、这些卵泡在身体后端的延伸以及它们不汇合的事实。通过分子数据证实了形态差异。对三个样本进行了测序，分子分析基于 28S 核糖体 RNA 基因的内部转录间隔区 2 和 D1-D3 结构域。获得的拓扑表明新物种是C.阿吉雷佩克诺伊，一种最初描述于墨西哥菊在墨西哥，后来发现于凤梨在哥斯达黎加。新物种的分离株是相互单系的，遗传距离值与在 Allocreadiidae 的其他物种对中观察到的相似。这些发现证实了该属甲壳虫主要是characids的寄生虫，并广泛分布于美洲，具有代表性的物种发生在阿根廷和墨西哥北部之间。