Spiders of the genus Cybaeus L. Koch, 1868 exhibit two major centers of diversity: Western North America and Japan. Several Japanese Cybaeus possess an elongated embolus in the male palp and elongated tubular spermathecae in the female genitalia. Here we describe Cybaeus koikeisp. nov. from central Honshu, Japan, which has an unelongated embolus and bulbous spermathecae. Phylogenetic analyses using nuclear and mitochondrial gene markers clearly support the monophyly of C. koikeisp. nov. and Cybaeus melanoparvus Kobayashi, 2006, a species with elongated genitalia. Both species share a similar habitus and a cluster of robust setae on the lateral surface of the male palpal patella. The latter is considered a synapomorphy for C. koikeisp. nov. and C. melanoparvus. A supplementary description of the spermathecae of C. melanoparvus is also provided.

中文翻译：

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来自日本中部的具有简单生殖器的新的Cybaeus L.Koch，1868年（Araneae，Cybaeidae）是具有小生殖器的C. melanoparvus Kobayashi的姊妹物种，2006年。

Cybaeus L. Koch属的蜘蛛具有两个主要的多样性中心：北美西部和日本。几只日本天鹅在男性的手掌中有一个细长的栓子，在女性的生殖器中有一个细长的管状的精子囊。在这里，我们描述Cybaeus koikeisp。十一月 来自日本本州中部，有不长的栓子和球茎的spermathecae。使用核和线粒体基因标记的系统发育分析清楚地支持了Koikeisp的单性。十一月 和Cybaeus melanoparvus Kobayashi，2006年，生殖器拉长。两种物种都具有相似的习性，并且在雄性pal骨骨的侧面上有一簇健壮的刚毛。后者被认为是小池角梭菌的一个突触。十一月 和C. melanoparvus。还提供了对黑色隐孢子虫精子的补充描述。