Taming the Red Bastards: Hybridisation and species delimitation in the Rhodanthemum arundanum-group (Compositae, Anthemideae)

Abstract Delineating species boundaries in a group of recently diverged lineages is challenging due 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.