Discussion
We found that environmentally heterogeneous ecotones influenced the
speed of trait evolution, affecting both the rate and time of diet
transitions in sigmodontine rodents. Ecotone species’ diet changed
little from the ancestral diet when compared to core species.
Furthermore, an interaction between position and habitat type indicated
that a broader environmental context dictates the rates and time of diet
evolution. Spatial variation on assemblage-level tip-based metrics
revealed regions with slow- and fast-evolving species. Finally,
phylogenetic uncertainty can influence the estimates of rates and time
of trait evolution, as well as the inference about the effect of
variables on such estimates.