Maldonado A, Simões R O, Luiz J São, Costa-Neto S F, Vilela R V
Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, FIOCRUZ, Rio de Janeiro, RJ, Brazil.
Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil.
J Helminthol. 2019 Jul 24;94:e68. doi: 10.1017/S0022149X19000610.
Nematodes of the genus Physaloptera are globally distributed and more than 100 species are known. Their life cycle involves insects, including beetles, cockroaches and crickets, as intermediate hosts. This study describes a new species of Physaloptera and reports molecular phylogenetic analyses to determine its relationships within the family Physalopteridae. Physaloptera amazonica n. sp. is described from the stomach of the caviomorph rodent Proechimys gardneri collected in the Amazon rainforest in the state of Acre, Brazil. The species is characterized by the male having the first and second pair of sessile papillae asymmetrically placed, lacking a median papilla-like protuberance between the third pairs of sessile papillae, differentiated by size and shape of the spicules, while females have four uterine branches. For both nuclear 18S rRNA and MT-CO1 gene-based phylogenies, we recovered Turgida sequences forming a clade nested within Physaloptera, thus making Physaloptera paraphyletic to the exclusion of Turgida, suggesting that the latter may have evolved from the former monodelphic ancestral state to a derived polydelphic state, or that some species of Physaloptera may belong to different genera. Relationships between most taxa within Physaloptera were poorly resolved in our phylogenies, producing multifurcations or a star phylogeny. The star-like pattern may be attributed to evolutionary processes where past simultaneous species diversification events took place. Physaloptera amazonica n. sp. formed an independent lineage, separately from the other species of Physaloptera, thus supporting the status of a new species. However, all molecular data suggested a closer relationship with other Neotropical species. In conclusion, we added a new species to this already largely diverse genus Physaloptera, bringing new insights to its phylogenetic relationships. Further analyses, adding more species and markers, should provide a better understanding of the evolutionary history of physalopterids.
泡翼属线虫分布于全球，已知有100多种。它们的生命周期涉及昆虫，包括甲虫、蟑螂和蟋蟀，作为中间宿主。本研究描述了泡翼属的一个新物种，并报告了分子系统发育分析，以确定其在泡翼科中的关系。亚马逊泡翼线虫新种是从巴西阿克里州亚马逊雨林采集的豚鼠形啮齿动物加氏原鼠的胃中描述的。该物种的特征是，雄性的第一对和第二对无柄乳突不对称放置，第三对无柄乳突之间没有中间乳突状突起，通过交合刺的大小和形状来区分，而雌性有四个子宫分支。对于基于核18S rRNA和MT - CO1基因的系统发育，我们恢复了Turgida序列，形成了一个嵌套在泡翼属内的分支，因此泡翼属是并系的，不包括Turgida，这表明后者可能是从前者的单子宫祖先状态进化到衍生的多子宫状态，或者泡翼属的一些物种可能属于不同的属。在我们的系统发育中，泡翼属内大多数分类单元之间的关系解析得很差，产生了多分支或星状系统发育。这种星状模式可能归因于过去同时发生物种多样化事件的进化过程。亚马逊泡翼线虫新种形成了一个独立的谱系，与泡翼属的其他物种分开，从而支持了新物种的地位。然而，所有分子数据都表明它与其他新热带物种关系更密切。总之，我们在这个已经种类繁多的泡翼属中增加了一个新物种，为其系统发育关系带来了新的见解。进一步的分析，增加更多的物种和标记，应该能更好地理解泡翼科的进化历史。
