The amphipod Ericthonius didymus Krapp-Schickel, 2013 is reported for the first time outside its type locality in European waters, from the French Atlantic coast and from the Azores, Portugal. In particular, a large population was recorded in Arcachon, France. Molecular analyses were made to confirm the validity of three closely related Ericthonius species: E. didymus, E. convexus and E. pugnax. An identification key is provided, distinguishing Ericthonius species into three groups, based on the presence or absence of stridulating ridges on coxa 2 and posterodistal lobe on basis of male pereopod 5.

中文翻译：

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欧洲水域 Ericthonius didymus Krapp-Schickel 的新记录，2013 年（甲壳纲：两足纲：Ischyroceridae），重点是法国阿卡雄湾和 Ericthonius 物种的关键

片脚类动物埃里克托尼乌斯Krapp-Schickel, 2013 首次在欧洲水域以外的地方被报道，来自法国大西洋沿岸和葡萄牙亚速尔群岛。特别是，在法国阿卡雄记录了大量人口。进行分子分析以确认三个密切相关的有效性埃里克托纽斯物种：E. didymus,E. 凸和E. pugnax. 提供一个识别键，区分埃里克托纽斯物种分为三组，根据雄足足 5 的基轴 2 和后远叶是否存在颤动脊。