Andres Michael J, Pulis Eric E, Curran Stephen S, Overstreet Robin M
Division of Coastal Sciences, The University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564, USA.
Division of Coastal Sciences, The University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564, USA; Department of Science and Mathematics, Northern State University, 1200 South Jay Street, Aberdeen, SD 57401, USA.
Parasitol Int. 2018 Dec;67(6):805-815. doi: 10.1016/j.parint.2018.08.002. Epub 2018 Aug 12.
Megasolena mikra sp. nov. is described from the queen angelfish, Holacanthus ciliaris (Linnaeus), off Florida, USA. The new species can be differentiated from all other species of Megasolena Linton, 1910 except Megasolena littoralis Muñoz, George-Nascimento, and Bray, 2017 in possessing testes that are smaller in diameter than the ovary. The new species can be differentiated from M. littoralis in lacking tegumental spines and possessing oral sucker papillae. Molecular data are provided for two species each of Cadenatella Dollfus, 1946, Hapladena Linton, 1910, and Megasolena Linton, 1910. Bayesian inference analysis of concatenated internal transcribed spacer region-2 (ITS2) and partial 28S rDNA sequences of 50 haploporoids revealed 1) a monophyletic Atractotrematidae Yamaguti, 1939 sister to the rest of the haploporoids tested; 2) a paraphyletic Megasoleninae Manter, 1935 - if Hapladena is included; and 3) a monophyletic Cadenatellinae Gibson and Bray, 1982 sister to the 'mugilid' haploporids. The 'mugilid' haploporids formed a monophyletic clade consisting of the subfamilies Chalcinotrematinae Overstreet and Curran, 2005, Forticulcitinae Blasco-Costa, Balbuena, Kostadinova, and Olson, 2009, Haploporinae Nicoll, 1914, and Waretrematinae Srivastava, 1937. Based on our analysis we restrict the Megasoleninae to include Megasolena, Vitellibaculum Montgomery, 1957, and Metamegasolena Yamaguti, 1970, all of which have species with two testes. To accommodate the former megasolenine taxa with a single testis, we erect the Hapladeninae subf. nov. for species in Hapladena and tentatively, Myodera Montgomery, 1957. Our results further support that haploporoids had a common marine ancestor with two testes, and that members of the Haploporoidea Nicoll, 1914 underwent diversification following a shift from a primarily marine life history with eupercarian hosts to a more euryhaline one with diadromous hosts (namely mullet).
新种微小巨泡吸虫（Megasolena mikra sp. nov.）是从美国佛罗里达州海域的女王神仙鱼（Holacanthus ciliaris，林奈）体内发现并描述的。除了2017年发现的滨海巨泡吸虫（Megasolena littoralis）外，该新物种与1910年林顿描述的所有其他巨泡吸虫物种不同，其睾丸直径小于卵巢。新物种与滨海巨泡吸虫的区别在于没有体表棘，且具有口吸盘乳头。文中提供了1946年多尔福斯描述的卡德内吸虫属（Cadenatella）、1910年林顿描述的单睾吸虫属（Hapladena）以及1910年林顿描述的巨泡吸虫属（Megasolena）各两个物种的分子数据。对50种单殖吸虫的串联内转录间隔区2（ITS2）和部分28S rDNA序列进行贝叶斯推断分析，结果显示：1）1939年山口描述的无管科（Atractotrematidae）为单系群，是其余受试单殖吸虫的姐妹群；2）如果将单睾吸虫属纳入，则1935年曼特尔描述的巨泡吸虫亚科（Megasoleninae）为并系群；3）1982年吉布森和布雷描述的卡德内吸虫亚科（Cadenatellinae）为单系群，是“鲻科”单殖吸虫的姐妹群。“鲻科”单殖吸虫形成一个单系分支，包括2005年奥弗斯特里特和柯伦描述的沙氏吸虫亚科（Chalcinotrematinae）、2009年布拉斯科 - 科斯塔、巴尔布埃纳、科斯塔迪诺娃和奥尔森描述的拟壳吸虫亚科（Forticulcitinae）、1914年尼科尔描述的单殖吸虫亚科（Haploporinae）以及1937年斯里瓦斯塔瓦描述的瓦氏吸虫亚科（Waretrematinae）。基于我们的分析，我们将巨泡吸虫亚科的范围限定为包括巨泡吸虫属、1957年蒙哥马利描述的卵囊吸虫属（Vitellibaculum）以及1970年山口描述的后巨泡吸虫属（Metamegasolena），所有这些属的物种都有两个睾丸。为了容纳以前具有单个睾丸的巨泡吸虫亚科分类单元，我们建立了新亚科单睾吸虫亚科（Hapladeninae subf. nov.），用于包含单睾吸虫属以及暂时包含1957年蒙哥马利描述的肌形吸虫属（Myodera）的物种。我们的结果进一步支持单殖吸虫有一个具有两个睾丸的共同海洋祖先，并且1914年尼科尔描述的单殖吸虫目（Haploporoidea）的成员在从主要以真软甲类宿主的海洋生活史转变为以洄游性宿主（即鲻鱼）的更广盐性生活史之后经历了多样化。
