Fig. 1

Reconstruction of the acquisition of a fully fossorial lifestyle among lepidosaurs. Non-fossorial lifestyle branches are in grey/black, fossorial ones (as indicated by node posterior probability over 50%) in light blue/dark blue. Phylogeny based on Pyron, Burbrink, and Wiens [41] with a time-calibration in accordance with Ramm et al. [42]. Additional lifestyle data obtained from Bars-Closel et al. [43]. Stochastic character mapping with phytools package [44]. For the taxa further investigated in this study (dark blue/black), the acquisition of a fully fossorial lifestyle is indicated by the numbers 1–21 (see Additional file 1: Table S4 for taxon names). These cover 85% of primary and 35% of secondary acquisitions in the major lepidosaur clades. For a high resolution version of Fig. 1, see Additional file 3