**mtDNA Divergence Dating in BEAST**
Here we provide our input xml file for BEAST, log file from the analysis, and the resulting maximum clade credibility tree file.
We conducted Bayesian divergence-dating analyses with our 16S mtDNA data set using BEAST v1.8 (Drummond et al. 2012). We performed analyses using a GTR substitution model, and a constant size coalescent tree prior with a strict molecular clock calibrated with an amphibian rate of 2% per Myr rate of divergence (Crawford 2003). Analyses were run for 100 million generations with sampling every 5,000 generations, producing a total of 20,000 trees. We examined convergence using Tracer version 1.6 (Rambaut & Drummond 2009), discarded a burn-in of 25% and generated a maximum clade credibility tree from 15,000 trees.