Achatz Tyler J, Von Holten Zoe S, Pritchard Jonathon, Keel Matthew
Department of Natural Sciences, Middle Georgia State University, Macon, GA, USA.
Department of Biology, Georgia Southern University, Statesboro, GA, USA.
Syst Parasitol. 2025 May 2;102(3):33. doi: 10.1007/s11230-025-10233-z.
Posthodiplostomum Dubois, 1936 is a diverse, widespread genus of diplostomoideans that parasitize as adults the intestines of piscivorous birds. Larvae of Posthodiplostomum spp. commonly cause the 'white grub' disease of fishes. During July 2024, we collected Posthodiplostomum spp. from green heron Butorides virescens and great egret Ardea alba in Georgia, USA, including two new species. We provide descriptions of both new species in the present study. Partial nuclear 28S rDNA and mitochondrial cox1 gene DNA sequences were generated for all collected species; newly obtained 28S sequences were used to study the phylogenetic interrelationships among Posthodiplostomum spp. The new species have a subspherical prosoma that is characteristic in only a few other species, notably Posthodiplostomum aztlanensis and Posthodiplostomum nanum which parasitize the same avian host species. Despite minimal morphological differences among Posthodiplostomum seminolense n. sp., Posthodiplostomum dawnsherryae n. sp., P. aztlanensis and P. nanum, these morphologically similar species differ by 0.5-5.9% in partial 28S sequences and 10.9-17.4% in partial cox1 sequences. The original description of P. nanum was based on immature specimens; we provide a new description of P. nanum based on previously sequenced specimens from a great egret in Mississippi, USA to allow better comparisons.
后双盘吸虫属（Posthodiplostomum）由杜波依斯于1936年建立，是双盘吸虫科中一个种类多样、分布广泛的属，其成虫寄生于食鱼鸟类的肠道。后双盘吸虫属的幼虫通常会引发鱼类的“白蛆”病。2024年7月，我们在美国佐治亚州从绿鹭（Butorides virescens）和大白鹭（Ardea alba）体内采集到了后双盘吸虫属的样本，其中包括两个新物种。在本研究中，我们对这两个新物种进行了描述。我们为所有采集到的物种生成了部分核28S核糖体DNA（rDNA）和线粒体细胞色素c氧化酶亚基1（cox1）基因的DNA序列；新获得的28S序列用于研究后双盘吸虫属各物种之间的系统发育关系。这两个新物种具有近球形的前体，这种特征仅在少数其他物种中出现，特别是寄生于相同鸟类宿主物种的阿兹特兰后双盘吸虫（Posthodiplostomum aztlanensis）和矮小后双盘吸虫（Posthodiplostomum nanum）。尽管塞米诺尔后双盘吸虫新种（Posthodiplostomum seminolense n. sp.）、唐恩·谢里后双盘吸虫新种（Posthodiplostomum dawnsherryae n. sp.）、阿兹特兰后双盘吸虫和矮小后双盘吸虫之间的形态差异极小，但这些形态相似的物种在部分28S序列上的差异为0.5 - 5.9%，在部分cox1序列上的差异为10.9 - 17.4%。矮小后双盘吸虫的原始描述基于未成熟标本；我们基于美国密西西比州一只大白鹭先前测序的标本，对矮小后双盘吸虫进行了新的描述，以便进行更好的比较。
