Laboratório de Biologia de Trematoda, Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, P.O. Box 486, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Department of Veterinary Medicine, Universidade Federal do Paraná, Curitiba, Brazil.
Acta Parasitol. 2024 Mar;69(1):1027-1034. doi: 10.1007/s11686-023-00738-2. Epub 2023 Nov 22.
Species of the genus Philophthalmus are eye flukes with a complex taxonomy, which began to be improved with the help of molecular data only recently. However, most described species have never been placed into a phylogenetic context. In this study, eye flukes previously found on kelp gulls, Larus dominicanus, from Brazil and identified as Philophthalmus lacrymosus were subjected to molecular analysis.
For the molecular analyses, we analyzed parasites found in six infected gulls (one worm per bird) collected from different municipalities of the state of Santa Catarina, Brazil. We carried out the amplification and sequencing of the partial region of the 28S and cox1 genes and the data obtained were compared with sequences available to philophthalmid species and subjected to phylogenetic analysis.
The isolates of P. lacrymosus from Brazil grouped in well-supported clades with five other species of Philophthalmus with sequences available for comparison. Interspecific divergences of 0.1-1.6% in 28S and 8.2-14.9% in cox1 were found in relation to other isolates of Philophthalmus spp. Two cox1 haplotypes differing in one nucleotide (0.1%) were found between the six eye flukes isolates in gulls from different localities. The Brazilian isolates grouped in a subclade with parasites identified as P. lacrymosus in Portugal; however, the molecular divergences found in cox1 (8.2-8.5%) strongly suggest that these isolates belong to different species. The phylogenetic trees obtained and the intergeneric divergences to species of the genera Cloacitrema and Parorchis did not support the validity of the genus Natterophthalmus, for which P. lacrymosus was proposed as the type species in the past.
As P. lacrymosus was described from Brazil, we recommend that this name be applied to the South American isolates and that the Portuguese isolates be provisionally considered as Philophthalmus sp., a probable cryptic species. Moreover, data obtained supports the previous morphology-based synonymizing between Natterophthalmus and Philophthalmus. Considering our results and most of previous reports of P. lacrymosus in South America, we suggest this species presents a marine life cycle.
眼舌蝇属的物种是具有复杂分类学的眼吸虫，最近才开始借助分子数据进行改进。然而，大多数已描述的物种从未被置于系统发育背景下。在这项研究中，对先前在巴西的海带鸥（Larus dominicanus）身上发现并鉴定为泪点舌蝇（Philophthalmus lacrymosus）的眼舌蝇进行了分子分析。
为了进行分子分析，我们对从巴西圣卡塔琳娜州不同城市采集的六只受感染海鸥（每只鸟一只虫）中发现的寄生虫进行了分析。我们对 28S 和 cox1 基因的部分区域进行了扩增和测序，并将获得的数据与可获得的 Philophthalmus 物种序列进行比较，并进行了系统发育分析。
巴西的 P. lacrymosus 分离株与其他可比较的 Philophthalmus 物种形成了支持度较高的分支。在 28S 中发现种间差异为 0.1-1.6%，在 cox1 中发现种间差异为 8.2-14.9%。在来自不同地点的海鸥的六只眼舌蝇分离株中发现了 cox1 单核苷酸差异（0.1%）的两种不同单倍型。巴西分离株与在葡萄牙鉴定为 P. lacrymosus 的寄生虫形成了一个亚分支；然而，cox1 中发现的分子差异（8.2-8.5%）强烈表明这些分离株属于不同的物种。获得的系统发育树和与 Cloacitrema 和 Parorchis 属物种的属间差异不支持 Natterophthalmus 属的有效性，过去曾提议将 P. lacrymosus 作为该属的模式种。
由于 P. lacrymosus 是从巴西描述的，我们建议将这个名称应用于南美洲分离株，而葡萄牙分离株暂被认为是 Philophthalmus sp.，可能是一个隐存种。此外，获得的数据支持了之前基于形态学的 Natterophthalmus 和 Philophthalmus 的同义词化。考虑到我们的结果和南美洲大多数关于 P. lacrymosus 的先前报告，我们建议该物种具有海洋生活史。
