Nematodes are one of the most widespread and abundant animal taxa across aquatic and terrestrial environments. In marine shallow-water, porous sediments, members of the subfamily Stilbonematinae may be found in high numbers. Stilbonematinae are characterized by their coat of symbiotic bacteria, which give the nematodes a white appearance, while the nematodes themselves are usually colourless. We identified several species of the genus Robbea (Desmodoridae: Stilbonematinae) in which live specimens had a conspicuous dark purple coloration of the glandular sense organs (GSOs), highly specialized epidermal glands that are prominent in the Stilbonematinae. The dark inclusions in the GSOs of Robbea contained high concentrations of iron and bromide, regardless of their habitat. Morphological and phylogenetic analyses show that the genus Robbea is paraphyletic and we define the new genus Cyathorobbea gen. nov. for species with sucker-shaped post-pharyngeal supplements in males. Furthermore, we describe five new Robbea species from around the world. Some Robbea species are morphologically very similar and required the use of principal component analysis of morphometric data to untangle the diversity in this taxon. Our work emphasizes the value of live animal observations that enable the identification of important characters and highlights the overlooked diversity within the Stilbonematinae.

中文翻译：

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Robbea 属（Stilbonematinae：Desmodoridae）的修订，世界范围内丰富的具有发色 Fe-Br 夹杂物的海洋线虫以及新的 Stilbonematine 属的描述

线虫是水生和陆地环境中分布最广泛、最丰富的动物类群之一。在海洋浅水多孔沉积物中，可能会发现大量的芪亚科成员。Stilbonematinae 的特征是其外壳有共生细菌，这使线虫具有白色外观，而线虫本身通常是无色的。我们鉴定了Robbea属（Desmodoridae：Stilbonematinae）的几个物种，其中活体标本的腺体感觉器官（GSO）呈明显的深紫色，这是Stilbonematinae中突出的高度特化的表皮腺体。罗贝亚 GSO 中的深色包裹体含有高浓度的铁和溴化物，无论其栖息地如何。形态学和系统发育分析表明，Robbea 属是并系群，我们定义了新属 Cyathorobbea gen。十一月 对于雄性具有吸盘状咽后补充物的物种。此外，我们描述了来自世界各地的五种新罗贝亚物种。一些罗贝亚物种在形态上非常相似，需要使用形态测量数据的主成分分析来理清该分类群的多样性。我们的工作强调了活体动物观察的价值，这些观察能够识别重要的特征，并强调了梯骨亚科中被忽视的多样性。