Pygopods are an exceptional radiation of snake-like geckos

Limb loss in vertebrate animals is surprisingly common despite imposing strong functional constraints. These pressures funnel species towards regions of limited ecological and phenotypic space. To date, snakes have been considered unique in having escaped these limitations. Using a new species-level phylogeny and comparative morphological and dietary datasets, we show that pygopods, a group of limbless Australo-Papuan geckos, have undergone a similar evolutionary trajectory to snakes. Our analyses provide evidence of exceptional morphological and dietary evolution. This is exemplified by strong niche partitioning among genera through dietary specialization and greater than expected dietary disparity. Diversification in pygopods has also been driven by extreme phenotypic evolution, with pygopods encompassing much of the morphological space covered by all other limb-reduced lizards. Interestingly, the diversification of pygopods has resulted in only a modest number of living species, emphasizing the decoupling of diversity and richness possible in adaptive radiations.