Valadão Marisa C, Alves Philippe V, López-Hernández Danimar, Assis Jordana C A, Coelho Paulo R S, Geiger Stefan M, Pinto Hudson A
Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, P.O. Box 486, 30123-970, Belo Horizonte, Minas Gerais, Brazil.
Section of Parasitology, Institute of Biosciences, São Paulo State University (UNESP), 18618-689, Botucatu, São Paulo, Brazil.
Parasitology. 2023 Apr;150(4):337-347. doi: 10.1017/S003118202300001X. Epub 2023 Jan 12.
, described in Brazil at the end of the 1960s and used as a biological model for a range of studies, belongs to the ‘’ complex of comprising species with 37 collar spines. However, molecular data are available only for a few isolates maintained under laboratory conditions, with molecular prospecting based on specimens originating from naturally infected hosts virtually lacking. The present study describes Valadão, Alves & Pinto n. sp., a species cryptically related to found in Brazil. Larval stages (cercariae, metacercariae and rediae) of the new species were found in the physid snail in the State of Minas Gerais, Brazil, the same geographical area where was originally described. Adult parasites obtained experimentally in were used for morphological (optical microscopy) and molecular [28S, internal transcribed spacer (ITS), 1 and 1] characterization. The morphology of larval and adult parasites (most notable the small-sized dorsal spines in the head collar), associated with low (0–0.1%) molecular divergence for 28S gene or ITS region, and only moderate divergence for the mitochondrial 1 gene (3.83%), might suggest that the newly collected specimens should be assigned to . However, higher genetic divergence (6.16–6.39%) was found in the mitochondrial 1, revealing that it is a genetically distinct, cryptic lineage. In the most informative phylogenetic reconstruction, based on 1, n. sp. exhibited a strongly supported sister relationship with . , which may indicate a very recent speciation event giving rise to these 2 species.
20世纪60年代末在巴西被描述，并被用作一系列研究的生物学模型，属于包含有37个颈棘物种的“”复合体。然而，分子数据仅适用于在实验室条件下保存的少数分离株，几乎缺乏基于自然感染宿主标本的分子勘探。本研究描述了在巴西发现的与隐秘相关的新物种瓦拉当、阿尔维斯和平托新种。在巴西米纳斯吉拉斯州的椎实螺中发现了新物种的幼虫阶段（尾蚴、后尾蚴和雷蚴），该地理区域也是最初被描述的地方。在中通过实验获得的成年寄生虫用于形态学（光学显微镜）和分子[28S、内部转录间隔区（ITS）、1和1]特征分析。幼虫和成年寄生虫的形态（最显著的是头环中的小型背棘），与28S基因或ITS区域的低分子差异（0-0.1%）以及线粒体1基因的中等差异（3.83%）相关，这可能表明新采集的标本应归为。然而，在线粒体1中发现了更高的遗传差异（6.16-6.39%），这表明它是一个遗传上不同的隐秘谱系。在基于1的信息量最大的系统发育重建中，新种与表现出强烈支持的姐妹关系。，这可能表明导致这两个物种的物种形成事件非常近。
