Fig. 1.

A time‐calibrated phylogeny, modified from Zheng & Wiens (2016) showing osteoderm (OD) abundance across extant lizard genera as taken from the literature, plotted over geological era, with outgroups. An expanded species‐level phylogeny is shown for Anguimorpha. Abundance is estimated as the proportion (% of species) within a clade that develop ODs: common, >50%; uncommon, 10–50%; rare, <10%. Prepared in R using packages phytools (Revell, 2012), Geiger (Pennell et al., ²⁰¹⁴), ape (Paradis & Schliep, 2019), and plotrix (Lemon, 2013).