Tkach Vasyl V, Curran Stephen S, Bell Jeffrey A, Overstreet Robin M
University of North Dakota, Department of Biology, Starcher Hall Box 9019, 10 Cornell St., Grand Forks, North Dakota 58202.
J Parasitol. 2013 Dec;99(6):1114-21. doi: 10.1645/13-279.1. Epub 2013 Aug 5.
A new species, Crepidostomum affine n. sp., is described from Hiodon tergisus in Mississippi, and morphological data are provided for Crepidostomum auritum from Aplodinotus grunniens in Mississippi and for Crepidostomum illinoiense from Hiodon alosoides in Minnesota. The new species is most similar morphologically to C. illinoiense, but has a shorter intertesticular space, measuring 0-74 μm (mean = 19.3 ± 23.1 SD in 73 specimens) compared with 0-229 μm (mean = 57.3 ± 56.7 SD in 34 specimens), and the distance between the ovary and the anterior testis is relatively shorter in the new species, representing 2.6-7.9% of overall body length compared with 4.1-12.4% in C. illinoiense. Fragments of nuclear ribosomal as well as mitochondrial DNA are compared among C. affine n. sp., C. illinoiense, C. auritum and Crepidostomum cornutum. Crepidostomum affine n. sp. and C. illinoiense are most similar, having between 19 and 20 variable bases (1.29-1.36%) in the amplified nuclear ribosomal RNA fragment comprising the complete ITS2 spacer and partial 28S gene, and between 35 and 39 variable bases (8.62-9.61%) in the amplified fragment of the COI region. Specimens of C. illinoiense from the Missouri River in North Dakota and Red Lake River in Minnesota differed by 1 base (0.07%) in the rRNA fragment and 4 bases (0.95%) in COI fragment. Crepidostomum cornutum and C. auritum also have 19 (1.29%) variable bases in the amplified ITS2 and partial 28S regions and 50 (12.32%) variable bases in the amplified COI region. Both C. cornutum and C. auritum demonstrated much greater levels of differences compared to C. affine n. sp. These results add to previously published data reporting species of fish digeneans that might be endemic to the Pearl and Pascagoula river basins in Mississippi.
在密西西比州，从大眼泥狗鱼（Hiodon tergisus）中描述了一种新物种，即仿形褶缘吸虫（Crepidostomum affine n. sp.），并提供了来自密西西比州的淡水石首鱼（Aplodinotus grunniens）体内的耳状褶缘吸虫（Crepidostomum auritum）以及来自明尼苏达州的似西鲱泥狗鱼（Hiodon alosoides）体内的伊利诺伊褶缘吸虫（Crepidostomum illinoiense）的形态学数据。新物种在形态上与伊利诺伊褶缘吸虫最为相似，但睾丸间距离较短，在73个标本中测量为0 - 74μm（平均值 = 19.3 ± 23.1 SD），而伊利诺伊褶缘吸虫在34个标本中为0 - 229μm（平均值 = 57.3 ± 56.7 SD）。新物种中卵巢与前睾丸之间的距离相对较短，占虫体全长的2.6 - 7.9%，而伊利诺伊褶缘吸虫为4.1 - 12.4%。对仿形褶缘吸虫新物种、伊利诺伊褶缘吸虫、耳状褶缘吸虫和角状褶缘吸虫（Crepidostomum cornutum）的核糖体以及线粒体DNA片段进行了比较。仿形褶缘吸虫新物种和伊利诺伊褶缘吸虫最为相似，在包含完整ITS2间隔区和部分28S基因的扩增核糖体RNA片段中有19至20个可变碱基（1.29 - 1.36%），在COI区域的扩增片段中有35至39个可变碱基（8.62 - 9.61%）。来自北达科他州密苏里河和明尼苏达州红湖河的伊利诺伊褶缘吸虫标本在rRNA片段中有1个碱基差异（0.07%），在COI片段中有4个碱基差异（0.95%）。角状褶缘吸虫和耳状褶缘吸虫在扩增的ITS2和部分28S区域也有19个（1.29%）可变碱基，在扩增的COI区域有50个（12.32%）可变碱基。与仿形褶缘吸虫新物种相比，角状褶缘吸虫和耳状褶缘吸虫的差异水平要大得多。这些结果补充了先前发表的数据，这些数据报告了可能是密西西比州珍珠河和帕斯卡古拉河流域特有的鱼类复殖吸虫物种。
