Congruence, fossils, and the evolutionary tree of rodents and lagomorphs

Given an evolutionary process, we expect distinct categories of heritable data, sampled in ever larger amounts, to converge on a single tree of historical relationships. We tested this assertion by undertaking phylogenetic analyses of a new morphology-DNA dataset for mammals, focusing on Glires and including the oldest known skeletons of geomyoid and Ischyromys rodents. Our results support geomyoids in the mouse-related clade (Myomorpha) and a ricochetal locomotor pattern for the common ancestor of geomyoid rodents. They also support Ischyromys in the squirrel-related clade (Sciuromorpha) and the evolution of sciurids and Aplodontia from extinct, \"protrogomorph\"-grade rodents. Moreover, ever larger samples of characters from our dataset increased congruence with an independent, well-corroborated tree. Addition of morphology from fossils increased congruence to a greater extent than addition of morphology from extant taxa, consistent with fossils' temporal proximity to the common ancest...