A new genus and species of crangonyctid amphipod, Sicifera cahawba gen. & sp. nov., is described from Dallas County, AL, USA, based on both morphological and molecular comparison with similar crangonyctids. These data, with the application of four species delimitation models, identify the taxon as distinct when compared with related species. Nearctic members of the crangonyctid genus Synurella form a separate, well-supported monophyletic lineage when compared with Palaearctic members, which differ considerably in both molecular and morphological markers. Nearctic members, with the exception of the enigmatic Synurella (Eosynurella) johanseni, are placed in the newly erected Sicifera. The separation of these two genera implies that Palaearctic and Nearctic crangonyctid lineages might not be as closely related as once thought, and their evolutionary and biogeographical history requires further review. In addition, a key to Nearctic members of the genera Eosynurella/Sicifera is presented to aid in future identification.

中文翻译：

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一种新淡水片脚类动物的系统发育分析揭示了 Holarctic 家族 Crangonyctidae 的多系性，并对 Synurella 属进行了修订

Sicifera cahawba gen 是一种新属和新种的长角端足类动物。＆sp。nov.，是从美国阿拉巴马州达拉斯县描述的，基于与类似的颅骨科动物的形态学和分子学比较。这些数据应用四种物种划分模型，与相关物种相比，将分类单元确定为不同的。与古北界成员相比，狭缝属 Synurella 的近北极成员形成了一个独立的、得到良好支持的单系谱系，后者在分子和形态标记上都有很大差异。近地成员，除了神秘的 Synurella (Eosynurella) johanseni 之外，都被放置在新竖立的 Sicifera 中。这两个属的分离意味着古北界和近北界 crangonyctid 谱系可能不像以前认为的那样密切相关，它们的进化和生物地理历史需要进一步审查。此外，还提供了 Eosynurella/Sicifera 属的 Nearctic 成员的一把钥匙，以帮助未来识别。