Shards, sequences, and shorelines: two new species of Bembidion from North America (Coleoptera: Carabidae)

Two new species of Bembidion are described from river shores in North America.  One, Bembidion mimbres sp. nov., from the Gila River watershed in the lands of the Mimbres culture in New Mexico and Arizona, is closely related to the widespread Bembidion levigatum. DNA sequences from several linkage groups provide evidence of the distinctiveness of B. mimbres. The second, Bembidion corgenoma sp. nov., has been the subject of recent genomic and transcriptomic studies.  It belongs in the Bembidion transversale subgroup, and occurs from California north to British Columbia, east to Montana and Nevada. The B. transversale subgroup as a whole is reviewed, and characters that distinguish B. corgenoma from the similar and sympatric B. transversale and B. erosum are described and illustrated.  DNA sequences of these three species show no consistent differences in 28S, COI, CAD, and Topoisomerase, and a coalescent species delimitation analysis reveals no notable structure within the complex. This ...本文记述了产自北美河岸的两个狭颊步甲属（Bembidion）新种。其中之一为Bembidion mimbres sp. nov.，其分布于新墨西哥州与亚利桑那州境内明布雷斯文化分布区的希拉河流域，与广布种Bembidion levigatum亲缘关系密切。多个连锁群的DNA序列数据证实了B. mimbres的物种独立性。 第二个新种为Bembidion corgenoma sp. nov.，目前已成为近期基因组学与转录组学研究的关注对象。该种隶属于Bembidion transversale亚组，分布范围北起加利福尼亚州至不列颠哥伦比亚省，东至蒙大拿州与内华达州。本文对B. transversale亚组整体进行了分类修订，并记述并图解了B. corgenoma与近缘同域物种B. transversale及B. erosum之间的鉴别特征。 对这三个物种的28S、COI、CAD及拓扑异构酶（Topoisomerase）基因序列分析显示，其未呈现稳定的序列差异；基于溯祖理论的物种界定分析也表明，该物种复合群内未存在显著的种群结构。此……