Blochmannia phylogeny estimated from a region of the 16S rDNA gene, analyzed with outgroups. The analysis includes 50 new bacterial sequences from Camponotini, 28 published Blochmannia sequences, and four mealybug endosymbionts that we found to be the closest relatives to Blochmannia. Taxa are labeled by the ant host from which the bacterial gene was amplified. The phylogeny was estimated using Bayesian methods, and the topology shown reflects the majority-rule consensus of post-burnin trees. Posterior probabilities of all nodes are marked. Taxon names of new samples are followed by a sample ID number, whereas published Blochmannia sequences are not. Like the unrooted tree (Figure 2), this rooted phylogeny resolved four major lineages within Blochmannia: Polyrhachis, Colobopsis, Opisthopsis, and a fourth group comprised of Camponotus, Calomyrmex, and Echinopla.