When adaptive radiations collide: different evolutionary trajectories between and within island and mainland lizard clades

Austin H. Patton, Luke J. Harmon, María del Rosario Castañeda, Hannah K. Frank, Colin M. Donihue, Anthony Herrel, Jonathan B. Losos

This repository holds the data and scripts associated with Patton et al. 2021 - When adaptive radiations collide: different evolutionary trajectories between and within island and mainland lizard clades, published in PNAS.

Abstract: Oceanic islands are known as test tubes of evolution. Isolated and colonized by relatively few species, islands are home to many of nature’s most renowned radiations from the finches of the Galápagos to the silverswords of the Hawaiian Islands. Despite the evolutionary exuberance of insular life, island occupation has long been thought to be irreversible. In particular, the much tougher competitive and predatory milieu on mainlands prevents colonization, much less evolutionary diversification, from islands back to mainlands. To test these postulates, we examined the ecological and morphological diversity of neotropical Anolis lizards, which have repeatedly dispersed between mainland South America and various islands in the Caribbean. We focus in particular on what happens when mainland and island evolutionary radiations collide. We show that extensive continental radiations can result from island ancestors and that the incumbent and invading mainland clades achieve their ecological and morphological disparity in very different ways. Moreover, we show that when a mainland radiation derived from island ancestors comes into contact with an incumbent mainland radiation, the ensuing interactions favor the island-derived clade.