Decoupled Patterns of Diversity and Disparity Characterize an Ecologically Specialized Lineage of Neotropical Cricetids

A link between morphological diversity and species richness is often implied in several evolutionary concepts, but conflicting results hamper a more direct link between these variables. Using a morphologically and ecologically diverse clade of Neotropical cricetids, Akodontini, we (1) characterized the tribe’s patterns of morphological disparity and lineage diversification, contrasting the two major clades; and (2) tested whether morphological disparity and rates of morphological evolution are associated with their lineage diversification patterns. We found no correlation between diversification rates and morphological patterns; instead, our results reveal a pattern of ecological and morphological diversification that is independent of cladogenetic events. We found higher rates of morphological evolution in lineages with longer independent evolutionary histories, leading to fewer, but more disparate and specialized species occupying the peripheral areas of the ecomorphospace and increasing the overall morphological diversity of the group.