Gradual adaptation toward a range-expansion phenotype initiated the global radiation of toads.
Recent studies have identified range expansion as a potential driver of speciation. Yet it remains poorly understood how, under identical extrinsic settings, differential tendencies for geographic movement of taxa originate and subsequently affect diversification. We identified multiple traits that predict large distributional ranges in extant species of toads (Bufonidae) and used statistical methods to define and phylogenetically reconstruct an optimal range-expansion phenotype. Our results indicate that lineage-specific range-shifting abilities increased through an accumulation of adaptive traits that culminated in such a phenotype. This initiated the episode of global colonization and triggered the major radiation of toads. Evolution toward a range-expansion phenotype might be crucial to understanding both ancient widespread radiations and the evolutionary background of contemporary invasive species such as the cane toad.
Biology Department, Amphibian Evolution Lab, Unit of Ecology and Systematics, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
Ines
I
Van Bocxlaer
Simon P
SP
Loader
Kim
K
Roelants
S D
SD
Biju
Michele
M
Menegon
Franky
F
Bossuyt
D000220:Adaptation, Biological; D000349:Africa; D000818:Animals; D001208:Asia; D001315:Australia; D001499:Bayes Theorem; D005075:Biological Evolution; D002025:Bufonidae / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics / Q000502:physiology; D049810:Genetic Speciation; D005843:Geography; D016013:Likelihood Functions; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D011157:Population Dynamics; D012098:Reproduction; D013020:South America; D013045:Species Specificity