Centro de Estudios Parasitológicos y Vectores (CEPAVE-UNLP-CONICET-), Boulevard 120 s/n e/60 y 64, C.P. 1900, La Plata, Buenos Aires, Argentina.
Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.P. 04510, Ciudad Universitaria, Mexico.
An Acad Bras Cienc. 2023 Nov 20;95(4):e20200668. doi: 10.1590/0001-3765202320200668. eCollection 2023.
During a search for parasites in fishes from Iguazu River, Argentina, a nymph of pentastomid was found encysted on mesenteries of Phalloceros harpagos. The 28S rDNA and COI mt-DNA were used to compare with the sequences deposited in the GenBank. Pentastomid nymphs belong to the subfamily Diesingiinae (Sebekidae) for having chloride cell pores distributed in a single row per annulus; also, the hooks and rows of spines of our material differ to other genera. Present specimens are most likely Diesingia sp., having 63-74 annuli, a U shaped oral cadre with fibers closing anteriorly and a peg like extension of the oral cadre. The 28S rDNA analysis places our samples into a sister group of Alofia sp., but the COI mt-DNA situate them on the base of the clade. In conclusion, our pentastomid positively belongs to Diesingia sp., however, indisputable assignation requires a reliable description of the nymph, or the availability of sequences linking nymphs and adults, which even could provide evidence of a new hitherto undescribed genus. Aditionally, the systematic position of Sebekia oxycephala previously described by P. harpagos is discussed on the basis of our results, allowing us to suggest a re-assignation of such specimens to the genus Diesingia.
在对阿根廷伊瓜苏河鱼类中的寄生虫进行搜索时，在 Phalloceros harpagos 的肠系膜上发现了一只五口线虫的若虫，已囊包。使用 28S rDNA 和 COI mt-DNA 与 GenBank 中已保存的序列进行比较。五口线虫的若虫属于 Diesingiinae 亚科（Sebekidae），因为它们的氯离子细胞孔分布在每个环的单列中；此外，我们的材料的钩和刺列与其他属不同。目前的标本很可能是 Diesingia sp.，具有 63-74 个环，U 形口板，纤维在前面关闭，口板的突起像钉子。28S rDNA 分析将我们的样本置于 Alofia sp. 的姊妹群中，但 COI mt-DNA 将它们置于分支的底部。总之，我们的五口线虫肯定属于 Diesingia sp.，然而，无可争议的归属需要对若虫进行可靠的描述，或者需要有连接若虫和成虫的序列，这甚至可以提供一个新的迄今未被描述的属的证据。此外，根据我们的结果，讨论了先前由 P. harpagos 描述的 Sebekia oxycephala 的系统位置，使我们能够建议将此类标本重新分配到 Diesingia 属。
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