Evolution, range formation and a revised taxonomy of the disjunctly distributed European members of Astragalus sect. Caprini, an intricate group including highly endangered species of dry grasslands.
Mayland C., & Kirschner P., Pirkebner D., Frajman B., Peñas de Giles J., Schönswetter P., Carnicero P. (2025). Evolution, range formation and a revised taxonomy of the disjunctly distributed European members of Astragalus sect. Caprini, an intricate group including highly endangered species of dry grasslands. Molecular Phylogenetics and Evolution - Volume 204. DOI
The Eurasian steppes are among the largest and most threatened biomes on Earth. During cold periods of the Pleistocene, the zonal Eurasian steppes had a much larger extent as compared to interglacial periods, and repeatedly expanded into large areas of present-day forested temperate Europe. Conversely, during warm periods, forest expansion recurrently forced Eurasian steppe biota into disjunct and small warm-stage refugia, i.e. today’s extrazonal steppes. The rare, threatened and disjunctly distributed northwestern African and European members of Astragalus sect. Caprini constitute an ideal model for gaining insights into the evolutionary dynamics of typical steppe biota. Here, we reconstructed the spatiotemporal diversification of northwestern African and European members of Astragalus sect. Caprini based on a combination of RADseq data, single gene markers (internal transcribed spacer, plastid ycf1), genome size measurements and multivariate morphometrics. We outline an evolutionary scenario in which the group originated in the Irano-Turanian region and started to diversify shortly after the Mid-Pleistocene-Transition (ca. 0.5 to 0.7 Ma). While lineages occurring in (sub-)mediterranean mountain ranges diverged early, lineages occurring in northern lowland steppes are much younger (ca. 0.2 to 0.3 Ma), emphasizing the importance of southern European mountain ranges as long-term refugia. Recurrent colonization of the western Mediterranean region by eastern Mediterranean lineages and secondary contacts of currently spatially isolated lineages have significantly (co-)shaped the genetic structure within the group; we assume that these events may be a consequence of cold-stage range expansions. Based on combined genetic and morphometric data, we suggest treating the ten lineages introduced in this study as independent species, contrasting previous taxonomic treatments.
Astragalus austrobalcanicus, a new species of Astragalus sect. Caprini from southern Albania and northern Greece
Mayland C., Kirschner P., Frajman B., Carnicero P., Schöenswetter P., (2025). Astragalus austrobalcanicus, a new species of Astragalus sect. Caprini from southern Albania and northern Greece. Phytotaxa: Vol. 690 No. 1. DOI
Figure 2. A, RAxML-tree based on RADseq data (modified from Maylandt et al., 2025). Taxa included in this study follow the color code in B and taxa which are not part of the present study are in grey. B, morphometric differentiation among A. austrobalcanicus, A. exscapus, A. hellenicus, A. pubiflorus and A. transsilvanicus as illustrated by a principal component analysis based on eleven uncorrelated characters. The scatterplot shows the position of studied samples in the reduced ordination space defined by the principal components 1 and 2. The arrows indicate the impact of the studied morphological characters on the distribution of the samples in the ordination space. The letters L, N, and W stand for length, number and width, respectively. Individuals with hairy standards are represented by symbols with broken outlines.
