Paleo-island morphometry
To test our hypotheses, we estimated the past insular areas and distances to the mainland in order to use these metrics as predictors of current species diversity. Herein, we were interested in the difference between the present-day geographical setting, the situation during the LGM and the situation under the median sea level over the last nine glacial-interglacial cycles (MSL - Norder et al. 2019). Hence, besides the present-day configuration of the Aegean islands, we used the work by Simaiakis et al. (2017 – Supplementary Material Appendix 1) for paleogeographical configurations. To investigate the biogeographical effects of past fragmentation from the mainland, we classified islands into two different groups: those that remained isolated from the mainland, referred to as “true islands” versus those with an episodic connection to the mainland during the LGM (“LGM land-bridge islands”) or at median sea level (“median land-bridge islands” - Simaiakis et al. 2017).