Data from: Comparative tests of the role of dewlap size in Anolis lizard speciation

Phenotypic traits may be linked to speciation in two distinct ways:
character values may influence the rate of speciation or diversification
in the trait may be associated with speciation events. Traits involved in
signal transmission, such as the dewlap of Anolis lizards, are often
involved in the speciation process. The dewlap is an important visual
signal with roles in species recognition and sexual selection, and dewlaps
vary among species in relative size as well as colour and pattern. We
compile a dataset of relative dewlap size digitized from photographs of
184 anole species from across the genus' geographical range. We use
phylogenetic comparative methods to test two hypotheses: that larger
dewlaps are associated with higher speciation rates, and that relative
dewlap area diversifies according to a speciational model of evolution. We
find no evidence of trait-dependent speciation, indicating that larger
signals do not enhance any role the dewlap has in promoting speciation.
Instead, we find a signal of mixed speciational and gradual trait
evolution, with a particularly strong signal of speciational change in the
dewlaps of mainland lineages. This indicates that dewlap size diversifies
in association with the speciation process, suggesting that divergent
selection may play a role in the macroevolution of this signalling trait.