Zoology Department, Faculty of Science, Cairo University, Cairo, Egypt.
Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
Mol Biol Rep. 2020 May;47(5):3705-3718. doi: 10.1007/s11033-020-05412-8. Epub 2020 Apr 6.
Thelandros is a genus of oxyurid nematodes which parasitize both omnivorous and herbivorous hosts. Thelandros chalcidiae sp. nov. is a new taxa described from the large intestine of the ocellated skink, Chalcides ocellatus, from the South Sinai Desert in Egypt. The recovered parasite species was examined at both morphological and molecular levels in order to determine the exact taxonomic position within Pharyngodonidae family. The current pharyngodonid species is characterized by a mouth opening bounded by three bilobed lips; male worms are characterized by the presence of two pairs of cloacal papillae (pre- and adcloacal) and one single caudal papillae (postcloacal) and caudal alae in an auricular form and females with post-equatorial vulva, amphidelphic ovary in which anterior ovary extended to level of excretory pore and posterior ovary extended posteriorly up anal opening. The recovered nematodes were compared with other known species from different hosts and it was found to be morphologically different from them. Molecular characterization based on the partial 28S rRNA nuclear ribosomal gene sequence showed sequence identities ≥ 83.15% with taxa under family Pharyngodonidae, 74.84-87.37% with Oxyuridae, 80.54% with Heteroxynematidae, and 75.98-77.72% with Thelastomatidea. Phylogenetic analysis showed that parasite sequence in conjunction with existing data facilitate placement of this species within Oxyurida. The present species is deeply embedded in genus Thelandros with close relationships to previously described Thelandros sp. and T. galloti in same taxon. This study highlighted importance of combining morphological and genetic data with taxonomy in pharyngodonid species.
兰德罗斯是寄生在杂食性和草食性宿主中的旋尾目线虫属。新种 Landros chalcidiae 是从埃及南西奈沙漠的眼斑蜥（Chalcides ocellatus）的大肠中描述的一种新分类群。为了确定在咽线虫科内的准确分类位置，对回收的寄生虫物种进行了形态和分子水平的检查。目前的咽线虫物种的特征是开口由三个三叶瓣状的唇所包围；雄虫的特征是有两对肛前和肛后肛乳头（pre- 和 adcloacal）和一个单一的尾肛乳头（postcloacal）和耳状的尾翼；雌虫具有后赤道部的阴道，两性的卵巢中，前卵巢延伸到排泄孔水平，后卵巢向后延伸到肛门开口。回收的线虫与来自不同宿主的其他已知物种进行了比较，发现它们在形态上与其他物种不同。基于部分 28S rRNA 核核糖体基因序列的分子特征表明，与咽线虫科中的分类群具有≥83.15%的序列同一性，与旋尾目科的其他物种具有 74.84-87.37%的序列同一性，与异形线虫科的其他物种具有 80.54%的序列同一性，与后气门目科的其他物种具有 75.98-77.72%的序列同一性。系统发育分析表明，寄生虫序列与现有数据相结合，有助于将该物种归入旋尾目科。本种在兰德罗斯属中深度嵌入，与以前描述的兰德罗斯属和同种的 T. galloti 密切相关。本研究强调了将形态和遗传数据与分类学相结合对咽线虫物种的重要性。
