Consolida and aconitella are an annual clade of delphinium (Ranunculaceae) that diversified in the mediterranean basin and the irano-turanian region

The Mediterranean and Irano-Turanian biogeographic regions are biodiversity hotspots for mesophytic and xerophytic species, including many Delphinieae. This phylogenetically poorly understood tribe of Ranunculaceae consists of Consolida and Aconitella, with together ca. 52 species, and Delphinium and Aconitum, each with ca. 300 species. To infer the phylogeny of Consolida and Aconitella, we analyzed nuclear and chloroplast DNA sequences from 39 of their species and subspecies (44 taxa) plus a set of 30 exemplar species of Delphinium and Aconitum. We used a Bayesian relaxed clock model to estimate divergence times and a maximum likelihood approach to reconstruct ancestral areas. Aconitella forms a clade embedded in Consolida, and the latter is embedded in Delphinium. Consolida s.l. (including Aconitella) comprises two clades in the Irano-Turanian region and three in the Mediterranean basin. The latter clades' inferred crown ages of 5.1, 4.4, and 2.8 Ma suggests that the repeated drying-up of the Mediterranean, concomitant with and following the Messinian salinity crisis (5.96-5.33 Ma), may have facilitated their westward expansion. While there is clear geographic structure towards the tips of the Consolida s.l. tree, a likely ancestral area could not be inferred. However, the initial diversification of Consolida s.l., which occurred ca. 17 Ma ago, falls in a period when the climate in the Anatolian region became more arid, which may have favoured the annual life cycle that characterizes all species in this clade. To achieve a classification of mutually monophyletic genera in Delphinieae may require transferring the species of Aconitella and Consolida into Delphinium.