Speciation/diversity is not associated with cranial disparity/evolution rate (in muroid rodents)

What is it about?

Muroid rodents are the most diverse superfamily of mammals. Many explanations have been proposed to explain diversity patterns within this group. Here, we use a recently published molecular phylogeny of the group along with three-dimensional cranial morphometric data to explore a potential explanation for muroid diversity patterns--that speciation/diversity is associated with cranial disparity/evolution rate. We do not find such an association in our dataset, indicating that clade richness is not associated with morphological divergence.

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Why is it important?

This is the third study in a series that explore the cause of uneven clade richness in muroid rodents. In the previous two studies we found that clade diversity/diversification rate was not associated with (1) ecological opportunity (colonization of new continents), nor (2) directional evolution in ecologically-important traits (diet, habitat, body size, and tail length). Here, we further show that clade diversity/diversification rate is not associated with (3) cranial disparity/evolution rate. Taken together, these studies show that further work needs to be done to uncover the main cause of uneven clade diversity in this extremely diverse clade.

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