The Palaearctic complex of anthidiine bees closely related to Pseudoanthidium scapulare has long been a source of unresolved taxonomic and systematic issues. Until now, the number of species in the complex and their geographical distributions were largely unclear, thus complicating the compilation of accurate species checklists and hindering conservation efforts. In order to address these issues, we use morphology and mitochondrial cytochrome c oxidase subunit I (COI) sequences, combined with a thorough examination of the relevant literature and type material, to delimit species within this complex, assign names to species and clarify geographical ranges. An unexpected result was that a certain number of morphologically distinct taxa exhibited low levels of genetic divergence at the COI locus, resulting in species paraphyly. A set of ultra-conserved elements (UCEs) was also sequenced in order to further investigate relationships among these taxa. One morphologically distinct species was also paraphyletic using UCE data, hinting at recent species divergences and genetic exchange at zones of contact between morphologically well-differentiated taxa. The results of our study reveal the presence of ten species in this complex, including a previously overlooked species for western continental Europe. A complete diagnosis of the males and females of these species is provided, as are maps detailing the geographic distributions of each. An illustrated identification key to the males and females of each species is presented. Two new species are described, Pseudoanthidium kaspareki sp. nov. and P. rozeni sp. nov. New synonymy is established for several species and Pseudoanthidium palestinicum and P. tropicum are raised to species level. The new combination, Icteranthidium floripetum comb. nov. is also established. Lectotypes are designated for the following species: Anthidium eversmanni, A. floripetum, A. frontale, A. karakalense, A. nanum and A. reptans. Previously unpublished lectotype designations are published here for A. sinuatum and A. tenellum.

中文翻译：

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形态学上不同分类群中的副系和低水平的遗传分歧：修订卡德蜂的肩胛假花复合体（Apoidea：Megachilidae：Anthidiini）

与 Pseudoanthidium scapulare 密切相关的古北界红地蜂群长期以来一直是未解决的分类和系统问题的根源。到目前为止，该综合体中的物种数量及其地理分布在很大程度上尚不清楚，从而使准确的物种清单的编制变得复杂，并阻碍了保护工作。为了解决这些问题，我们使用形态学和线粒体细胞色素 c 氧化酶亚基 I (COI) 序列，结合对相关文献和类型材料的彻底检查，在这个复合体中划定物种，为物种命名并阐明地理范围. 一个意想不到的结果是，一定数量的形态上不同的分类群在 COI 基因座处表现出低水平的遗传分歧，导致物种并系。为了进一步研究这些分类群之间的关系，还对一组超保守元素 (UCE) 进行了测序。使用 UCE 数据，一种形态上不同的物种也是并系的，暗示了最近的物种分歧和形态分化良好的分类群之间接触区的遗传交换。我们的研究结果揭示了这个复合体中存在十种物种，包括一个以前被忽视的西欧物种。提供了对这些物种的雄性和雌性的完整诊断，以及详细说明每个物种的地理分布的地图。展示了每个物种的雄性和雌性的图解识别键。描述了两个新物种，Pseudoanthidium kaspareki sp。十一月 和 P. rozeni sp。十一月 为几个物种建立了新的同义词，Pseudoanthidium pastinicum 和 P. tropicum 被提升到物种水平。新组合，Icteranthidium floripetum 梳子。十一月 也成立。选型被指定用于以下物种：Anthidium eversmanni、A. floripetum、A. frontale、A. karakalense、A. nanum 和 A. reptans。以前未发表的选型名称在此发布，用于 A. sinuatum 和 A. tenellum。