Diplostomum ardeae Dubois, 1969 has seldom been reported since its description from the great blue heron (Ardea herodias L., 1758) in the USA. Sequences obtained in this study from the barcode region of cytochrome c oxidase 1 (CO1) in diplostomids from black-crowned night heron (Nycticorax nycticorax (L., 1758)) in Puerto Rico matched data from D. ardeae from A. herodias in the type region. We also obtained DNA barcodes from morphologically similar diplostomids from a rufescent tiger heron (Tigrisoma lineatum (Boddaert, 1783)) and from metacercariae from eye lenses of Trachelyopterus galeatus (Linnaeus, 1766) from the Paraná River basin in Argentina and Brazil, respectively. Barcodes matched (97–100% identity) in these South American adult and larval specimens as well as in recently published sequences from metacercariae from 11 other siluriform fishes from the same region. Barcodes from the South American species, which we describe as Diplostomum lunaschiae n. sp., differed from those of D. ardeae by 7.2–9.8%, and the new species differs from D. ardeae in its size, pharynx:oral sucker length ratio, egg:body length ratio, and distribution of vitellaria. As in prior phylogenetic analysis of CO1 sequences, both D. ardeae and D. lunaschiae n. sp. were not associated with Diplostomum. In more character-rich analyses of nuclear rDNA and of mitochondrial genomes, D. ardeae was an early divergent member of clades of species of Diplostomum. Consequently, we continue to consider D. ardeae and D. lunaschiae n. sp. members of Diplostomum, in contrast to recent suggestions that these species may belong to a different genus.

自从美国的蓝鹭（Ardea herodias L.，1758）对其进行描述以来，很少有Diplostomum ardeae Dubois，1969年的报道。从细胞色素的条形码区域在这项研究中获得的序列Ç氧化酶1（CO1）在从夜鹭（diplostomids夜鹭Nycticorax夜鹭（L.，1758））在波多黎各匹配数据从D. ardeae从A.希罗底在类型区域。我们还获得的DNA条形码从一个rufescent虎鹭（形态上类似于diplostomids Tigrisoma皮蝇从眼透镜（Boddaert，1783））和从囊蚴Trachelyopterus galeatus（Linnaeus，1766年）分别来自阿根廷和巴西的巴拉那河流域。在这些南美成虫和幼体标本中，以及在最近发布的同一地区的其他11种sil形目鱼类的cer尾中，条形码都与条形码相符（97-100％相同）。来自南美物种的条形码，我们称其为Diplostomum lunaschiae n。sp。，与荷兰杜鹃D. ardeae相差7.2–9.8％，并且新物种与荷兰杜鹃D. eaeae的大小，咽：口吸盘长比，卵：体长比和黄tell分布不同。与以前对CO1序列进行的系统发育分析中一样，D。ardeae和D. lunaschiae n.。sp。与梁龙不相关。在对核rDNA和线粒体基因组进行更具特征的分析中，阿迪氏菌是Diplostomum物种进化枝的早期分化成员。因此，我们将继续考虑D. ardeae和D. lunaschiae n。sp。Diplostomum的成员，与最近有关这些物种可能属于不同属的建议相反。