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

作者：Clemens Maylandt, Philipp Kirschner, D. Pirkebner, Božo Frajman, Julio Peñas, Peter Schönswetter, Pau Carnicero · 发表于：Molecular Phylogenetics and Evolution · 年份：2024 · DOI：10.1016/j.ympev.2024.108242 · 被引用次数：4 · 研究领域：Plant Ecology and Taxonomy Studies、Botany, Ecology, and Taxonomy Studies、Botany and Plant Ecology Studies

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 lineag...