(1) The relaxed Bayesian clock method following the methodology outlined in Matthee et al. was used to date the evolution of the various chiropteran lineages.(2) The limitation of using single markers for resolving family-level chiropteran relationships was highlighted by the results obtained from analyses of individual nuclear intron fragments.(3) The molecular phylogeny presented here is consistent with either two independent origins of echolocation within the chiropteran lineage or a single origin.
