Delineating species boundaries in a group of recently diverged lineages is challenging due to minor morphological differences, low genetic differentiation and the occurrence of gene flow among taxa. Here, we employ traditional Sanger sequencing and restriction-site associated DNA (RAD) sequencing, to investigate species delimitation in the close-knit Moroccan daisy group around Rhodanthemum arundanum B.H.Wilcox & al. that diverged recently during the Quaternary. After evaluation of genotyping errors and parameter optimisation in the course of de-novo assembly of RADseq reads in Ipyrad, we assess hybridisation patterns in the study group based on different data assemblies and methods (Neighbor-Net networks, FastStructure and ABBA-BABA tests). RADseq data and Sanger sequences are subsequently used for delimitation of species, using both, multi-species coalescent methods (Stacey and Snapp) and a novel approach based on consensus k-means clustering. In addition to the unveiling of two novel subspecies in the R. arundanum-group, our study provides insights into the performance of different species delimitation methods in the presence of hybridisation and varying quantities of data.

中文翻译：

---

驯服红色杂种：在杜鹃红景天组（菊科，菊科）中的杂交和物种定界。

由于形态上的微小差异，低遗传分化和分类群之间的基因流的出现，在一组最近分化的世系中划定物种边界是一项挑战。在这里，我们采用传统的Sanger测序和限制性酶切位点相关DNA（RAD）测序，以研究杜鹃花Rhodanthemum arundanum BHWilcox等人周围的紧密联系的摩洛哥雏菊组中的物种划界。在第四纪期间最近发生了分歧。在对Ipyrad的RADseq读段进行反装配后，对基因分型错误进行了评估并优化了参数后，我们根据不同的数据装配和方法（邻居网络，FastStructure和ABBA-BABA测试）评估了研究组中的杂交模式。 。随后使用RADseq数据和Sanger序列对物种进行定界，多物种合并方法（Stacey和Snapp）以及基于共识k均值聚类的新颖方法。除了揭露了阿伦丹草组中的两个新亚种之外，我们的研究还提供了对存在杂交和不同数量数据时不同物种划界方法的性能的见解。