Format: ORAL

Thibaud F.E. Messerschmid1, Stefan Abrahamczyk2, ngel Baares-Baudet3, Miguel A. Brilhante4, Urs Eggli5, Philipp Hu¨hn6, Joachim W. Kadereit6,7, Patrcia dos Santos4,8, Jurriaan M. de Vos8 Gudrun Kadereit1,7

1 Botanischer Garten München-Nymphenburg, München, Germany 2 Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany 3 Universidad de La Laguna, San Cristóbal de La Laguna, Spain 4 Universidade de Lisboa, Lisboa, Portugal 5 Sukkulenten-Sammlung Zürich/Grün Stadt Zürich, Zürich, Switzerland 6 Johannes Gutenberg-Universität Mainz, Mainz, Germany 7 Ludwig-Maximilans-Universität München, München, Germany 8 Universität Basel, Basel, Switzerland

TheAeoniumalliance (Crassulaceae) is the most species-rich and ecologically diverse plant radiation on the Canary Islands. In such radiations, speciation can take place either within islands or following dispersal between islands. By quantifying intra- and inter-island speciation events in the evolution ofAeoniumand exploring their correlates, we hypothesized that (1) intra-island diversification resulted in stronger ecological divergence of sister lineages, and that (2) taxa on islands with a longer history of habitation byAeoniumshow stronger ecological differentiation and produce fewer natural hybrids. We studied the biogeographical and ecological setting of diversification processes inAeoniumwith a fully sampled and dated phylogeny inferred using a ddRADseq approach. Ancestral areas and biogeographical events were reconstructed in BioGeoBEARS. Eleven morphological characters and three habitat characteristics were taken into account to quantify the morphological and ecological divergence between sister lineages. In lineages that diversified within single islands, morphological and ecological divergence was stronger than in lineages derived from inter-island diversification, but only the difference in morphological divergence was significant. Those islands with the longest history of habitation byAeoniumhad the lowest percentages of co-occurring and hybridizing taxon pairs compared to islands colonized byAeoniummore recently. Our findings illustrate the importance of both inter- and intra-island speciation in island radiations, of which only the latter is potentially sympatric speciation.