Apparent effect of range size and fruit colour on palm diversification may be spurious

Aim Fruit selection by animal dispersers with different mobility directly impacts plant geographical range size, which, in turn, may impact plant diversification. Here, we examine the interaction between fruit colour, range size and diversification rate in palms by testing two hypotheses: (1) species with fruit colours attractive to birds have larger range sizes due to high dispersal ability and (2) disperser mobility affects whether small or large range size has higher diversification, and intermediate range size is expected to lead to the highest diversification rate regardless of disperser.Location Global.Time Period Contemporary (or present).Major Taxa Studied Palms (Arecaceae).Methods Palm species were grouped based on likely animal disperser group for given fruit colours. Range sizes were estimated by constructing alpha convex hull polygons from distribution data. We examined disperser group, range size or an interaction of both as possible drivers of change in diversification rate over time in a likelihood dynamic model (Several Examined State-dependent Speciation and Extinction [SecSSE]). Models were fitted, rate estimates were retrieved and likelihoods were compared to those of appropriate null models.Results Species with fruit colours associated with mammal dispersal had larger ranges than those with colours associated with bird dispersal. The best fitting SecSSE models indicated that the examined traits were not the primary driver of the heterogeneity in diversification rates in the model. Extinction rate complexity had a marked impact on model performance and on diversification rates.Main Conclusions Two traits related to dispersal mobility, range size and fruit colour, were not identified as the main drivers of diversification in palms. Increased model extinction rate complexity led to better performing models, which indicates that net diversification should be estimated rather than speciation alone. However, increased complexity may lead to incorrect SecSSE model conclusions without careful consideration. Finally, we find palms with more mobile dispersers do not have larger range sizes, meaning other factors are more important determinants of range size

The imprints left by historical contingency on marsupials' life-history traits

Historical contingency may lead to distinct evolutionary imprints in early-isolated taxonomic groups. Here, we used comparative phylogenetics to unravel biogeographical imprints left by distinct historical contingencies on the evolutionary patterns of life-history traits of an iconic group, currently separated by ocean-wide distance: the marsupials. Australasian and New World marsupial communities share a common ancestry but were subjected to different biogeographic histories: while the Australasian community was effectively isolated from other faunas since disruption of land bridges with Antarctica, the evolution of New World marsupials was affected by the Great American Biotic Interchange. Contrary to our expectations, the exuberant diversity of life-history traits on Australasian marsupials did not exhibit evidence of early bursts of evolution, as expected on adaptive radiations. That surprising result is probably related to the assumptions of the ecological opportunities scenario - sensu Simpson (Tempo and mode in evolution, Columbia University Press, New York, 1994), which are hard to be met in continental scales. On the other hand, New World marsupials showed patterns of evolution consistent with niche conservatism, possibly due to the constraining effect of biotic interactions on niche evolution. Therefore, biotic interactions seem to have the limited evolution of New World life-history traits, whereas Australasian marsupials diverged into spectacular forms, though in a gradual and constant rate. The distinct biogeographic histories of the New World and Australasian marsupials thus provide a unifying explanation for the divergence patterns found in their life-history traits3072149158COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESnão te