Phylogeography of north-eastern Australia’s Cyrtodactylus radiation: a habitat switch highlights adaptive capacity at a generic level

Abstract

The genus Cyrtodactylus is the most diverse and widely distributed group of geckos in the world. Throughout their extensive range, species exploit a diverse range of habitats and are able to partition niches locally. Recent work has shown that Cyrtodactylus geckos in Queensland, Australia, have radiated in situ after colonisation by an arboreal Papuan ancestor and have undergone a habitat switch to rock dwelling during their evolutionary history. Using mitochondrial data we conducted a phylogeographic and molecular dating analysis to investigate the historical biogeography of Cyrtodactylus species in north Queensland. Our analyses show that after the arrival of a Papuan rainforest-dwelling ancestor, Cyrtodactylus diverged into two major lineages: one more restricted in northern Cape York and the other more widespread. Discordance in the timing of the speciation events and phylogeographic distribution within the two lineages likely reflect regional differences in the continuity of mesic rock habitats and climatic variability over the last 15 million years. Reconstructing the history of habitat use on a pre-existing global phylogeny reveals that switches between major habitat ecologies, rock and forest, have occurred multiple times in this genus. The ability to transition between different habitat types may have contributed to the global diversification of these geckos.