Curran Stephen S, Pulis Eric E, Andres Michael J, Overstreet Robin M
1 Division of Coastal Sciences, The University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, Mississippi 39564.
2 The Institute for Marine Mammal Studies, 10801 Dolphin Lane, Gulfport, Mississippi 39503.
J Parasitol. 2018 Jun;104(3):221-239. doi: 10.1645/17-189. Epub 2018 Mar 16.
Two cryptic species of haploporid digeneans belonging in Saccocoelioides are described from Costa Rica: one from a poeciliid fish, Poecilia gillii, and the other from a characid fish, Astyanax aeneus. Traditional morphological features are examined and found to be largely inefficient for differentiating among the new species and 20 New World congeners. Comparison of ribosomal DNA sequences among the 2 new species, 2 North American, 4 Middle American, and 3 South American species of Saccocoelioides, including the type-species Saccocoelioides nanii from Argentina and Saccocoelioides sogandaresi from Texas, is effective in differentiating among these species. A Bayesian inference analysis is conducted using a concatenated alignment of the same 2 ribosomal gene regions from 35 species belonging in the Haploporoidea and rooted by the atractotrematid Isorchis anomalus. The analysis provides stronger support for a close relationship between species in Saccocoelioides and Intromugil; thus, Intromugil is transferred from the Waretrematinae to the Chalcinotrematinae. Additionally, interrelationships among 11 species of Saccocoelioides are resolved and reveal a distinct genetic rift suggesting the presence of 2 distinct lineages within the genus, 1 containing the type-species and the other containing a group of species that more closely resemble other genera in the subfamily. Taxonomy of Saccocoelioides is discussed, and observations made during the present study justify taking several taxonomic actions: new combinations are proposed for Saccocoelioides tilapiae n. comb., formerly in the now-defunct Culuwiya, and Saccocoelioides ruedasueltensis n. comb., formerly in Chalcinotrema; Saccocoelioides guaporense nomen novem is proposed for Lecithobotrioides elongatus; Saccocoelioides papernai is considered a junior subjective synonym of Saccocoelioides overstreeti; Saccocoelioides godoyi is considered a junior subjective synonym of Saccocoelioides szidati; Saccocoelioides magnorchis and Saccocoelioides saccodontis are considered species inquirendae; and Saccocoelioides adelae is considered a nomen nudum. Four new hosts are reported for Saccocoelioides cichlidorum: Amphilophus lyonsi, Amatitlania nigrofasciatus, Amatitlania septemfasciatus, and Hypsophrys nicaraguensis. Molecular data call into question some existing species identifications in Saccocoelioides and reveal that molecular tools combined with traditional taxonomy are required for accurately identifying species in the genus. Twenty-two species of Saccocoelioides are formally accepted, but it is noted that as new molecular data become available, some of these species may be transferred to other genera in the subfamily.
一种来自食蚊鱼科鱼类吉利食蚊鱼，另一种来自脂鲤科鱼类铜色丽脂鲤。研究了传统形态特征，发现其在区分新物种与20种新大陆同属物种方面大多效率低下。对2个新物种、2个北美洲物种、4个中美洲物种和3个南美洲物种的拟囊腔科物种，包括来自阿根廷的模式种纳尼拟囊腔吸虫和来自得克萨斯州的索甘达雷西拟囊腔吸虫的核糖体DNA序列进行比较，有效地区分了这些物种。使用来自35种属于单殖吸虫超科的相同2个核糖体基因区域的串联比对进行贝叶斯推断分析，并以异形异睾吸虫为根。该分析为拟囊腔科物种与银口鲻属之间的密切关系提供了更强的支持；因此，银口鲻属从沃氏吸虫亚科转移到钙吸虫亚科。此外，解决了拟囊腔科11个物种之间的相互关系，并揭示了一个明显的遗传分歧，表明该属内存在2个不同的谱系，一个包含模式种，另一个包含一组与亚科中其他属更相似的物种。讨论了拟囊腔科的分类学，本研究中的观察结果证明采取以下几个分类学行动是合理的：为原属于现已不存在的库卢维亚属的蒂氏拟囊腔吸虫提出新组合，为原属于钙吸虫属的鲁埃达苏埃尔滕西拟囊腔吸虫提出新组合；为长形卵磷脂吸虫提出新名称瓜波雷拟囊腔吸虫；认为帕佩尔纳拟囊腔吸虫是奥弗斯特里特拟囊腔吸虫的次主观同物异名；认为戈多伊拟囊腔吸虫是齐达蒂拟囊腔吸虫的次主观同物异名；认为大睾拟囊腔吸虫和食囊拟囊腔吸虫为待考物种；认为阿德拉拟囊腔吸虫为裸名。报告了丽鱼拟囊腔吸虫的4个新宿主：莱昂氏丽体鱼、黑带阿玛蒂丽鱼、七带阿玛蒂丽鱼和尼加拉瓜高鳍丽鱼。分子数据对拟囊腔科中一些现有的物种鉴定提出了质疑，并表明需要将分子工具与传统分类学相结合来准确鉴定该属中的物种。正式接受了22种拟囊腔科物种，但指出随着新的分子数据可用，其中一些物种可能会被转移到亚科中的其他属。
