Limnebius exhibits uniform external appearance but variable male genitalia: from differently curved rod shapes in the subgenus Bilimneus to up to seven longitudinally separated folds or appendages in Limnebius s.s.. Among nonsexual traits, two subgenera diverge only in the wing. The aedeagal complexity in Limnebius s.s. is associated with the secondary sexual structures on the abdomen and metatibia; larger body size, which forms two clusters; and male-biased sexual dimorphism. To cluster the subdivisions with phylogenetically unresolved relationships, we examined the coincidence of the traits in both sexes, based on the premise of the independent and monophyletic origin of histologically unsimilar elements. The folds and additional appendages on the median lobe, abdominal paired rows of setae, and protuberances show that the L. parvulus and L. nitidus groups have maximum aedeagal complexity in the L. parvulus and L. nitiduloides subgroups, respectively. The L. parvulus group exhibits a gradual increase in the number of elements of the aedeagi. The histology of connections of the parameres and additional appendages to the median lobe, along with that of the flagellum opening, reveal the subgroups’ relationship in the L. nitidus group, as well as a decrease in the complexity of the male genitalia in their recent branches.

中文翻译：

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形态多样化，重点是 Limnebius 属雄性生殖器的结构和同源模式（Leach 1815；Hydraenidae：鞘翅目）


Limnebius 表现出统一的外观，但雄性生殖器变化多端：从 Bilimneus 亚属中不同弯曲的杆状到 Limnebius ss 中多达七个纵向分离的褶皱或附属物。在非性特征中，两个亚属仅在翅膀上存在分歧。 Limnebius ss 的腺体复杂性与腹部和后胫骨的第二性结构有关。体型较大，形成两个簇；以及男性偏向的性别二态性。为了对系统发育上未解决的关系的细分进行聚类，我们基于组织学上不相似的元素的独立和单系起源的前提，检查了两性特征的一致性。中叶上的褶皱和附加附属物、腹部成对的刚毛行和突起表明，L. parvulus 和 L. nitidus 群体分别在 L. parvulus 和 L. nitiduloides 亚群中具有最大的腺体复杂性。 L. parvulus 群体表现出阳茎元素数量逐渐增加。副节和附加附属物与中叶的连接的组织学，以及鞭毛开口的连接，揭示了亮丝线虫组中各亚组的关系，以及最近发现的雄性生殖器复杂性的下降。分支机构。