Ecological opportunity and ecomorphological convergence in Australasian robins (Petroicidae)

Ecological theories of adaptive radiation predict that ecological opportunity (EO) stimulates cladogenesis through entry into a novel environment and/or release of competition pressures. Due to its dynamic paleoclimatic and geological history, the Australo-Papuan region constitutes an opportune scenario to study patterns of diversification in relation to the colonization of new ecological niches. Here, we employ a comparative framework using the Australasian robins (Petroicidae) as a model system to test whether the diversification of this bird family fulfils a niche-filling process as predicted by the EO model, and to test whether the observed morphological similarity is described by a pattern of phylogenetic niche conservatism (PNC) or convergence. Although we detected an early-burst, we did not find a slowdown in speciation or morphological evolution as expected in a niche-filling scenario. Divergence in tarsus length and tail length (PC1) was consistent with a multi-peak model, in w...