Abstract
Extinct organisms provide crucial information about the origin and time of origination of extant groups. The importance of morphological phylogenetics for rigorously dating the tree of life is now widely recognized and has been revitalized by methodological developments such as the application of tip-dating Bayesian approaches. Traditionally, molecular clocks have been node calibrated. However, node-calibrations are often unsatisfactory because they do not allow the fossil age to inform about phylogenetic hypothesis. The introduction of tipcalibrations allow fossil species to be included alongside their living relatives, and the absence of molecular sequence data for these taxa remedied by supplementing the sequence alignments for living taxa with phenotype character matrices for both living and fossil taxa. So, only phylogenetic analyses that take into account morphological characters can incorporate both fossil and extant species. Herein we present an unprecedented morphological dataset for a vast group of glirid rodents, to which different phylogenetic methodologies have been applied. We have compared the tree topologies resulting from 2 traditional parsimony and Bayesian phylogenetic approaches and calculate stratigraphic congruence indices for each. Bayesian tip-dated clock methods seem to outperform parsimony with our dataset. The strict consensus tree recovered by tip-dating invalidates the classic classification and allow to propose dates for the divergence and origin of the different clades.