Kansai Research Center, Forestry and Forest Products Research Institute, 68 Nagaikyutaroh, Momoyama, Fushimi, Kyoto, 612-0855, Japan.
School of Agriculture, Meiji University, Kawasaki, Kanagawa, 214-8571, Japan.
Sci Rep. 2023 Apr 20;13(1):6470. doi: 10.1038/s41598-023-33586-1.
A diplogastrid nematode was isolated from a dung beetle, Onthophagus sp., collected from a rotten mushroom in Kyoto, Japan. The species is characterised by its cheilostomatal shape, separated into 12 narrow plates (rugae), deep stegostom, large ellipsoidal amphids, conical female tail and characteristic receptaculum seminis in the female. Based on its phylogenetic status and stomatal composition, the species is typologically similar to two other diplogastrid genera, Neodiplogaster and Mononchoides. The species can be distinguished from these two genera by the size and shape of the amphid (small pore in Neodiplogaster), female tail shape (long and filiform in Mononchoides) and presence of receptaculum seminis (absence in the two nominal genera), and is described as a monotypic member of a new genus, Onthodiplogaster japonica n. gen., n. sp. Observation of feeding behaviour suggested that O. japonica n. gen., n. sp. does not show clear stomatal dimorphism or polymorphism, which is found in its close relatives, but the species can feed on nematodes (predation), fungi and bacteria. This monomorphic omnivory possibly represents its habitat of dung and other rotten materials, where the environment is biologically divergent, and its condition changes rapidly.
从日本京都腐烂蘑菇上采集的粪金龟 Onthophagus 中分离出一种双胃线虫。该物种的特征为口孔形状，分为 12 个狭窄的板（皱襞）、深的侧唇、大型的卵圆型领乳突、锥形的雌性尾部和雌性特有的贮精囊。根据其系统发育地位和口孔组成，该物种在形态上与另外两个双胃线虫属 Neodiplogaster 和 Mononchoides 相似。该物种可通过领乳突的大小和形状（Neodiplogaster 为小孔）、雌性尾部形状（Mononchoides 为长而丝状）和贮精囊的存在（在两个命名属中不存在）与这两个属区分开来，并被描述为一个新属 Onthodiplogaster 的单种属，即日本双胃线虫 n. gen., n. sp.。摄食行为的观察表明，日本双胃线虫 n. gen., n. sp. 没有表现出与其近亲相似的明显口孔二态性或多态性，但该物种可以捕食线虫（捕食）、真菌和细菌。这种单态的杂食性可能代表了它的粪和其他腐烂物质的栖息地，在那里环境具有生物多样性，并且其条件变化迅速。
