Figure 2 in Not just cryptic, but a barcode bush: PTP re-analysis of global data for the bumblebee subgenus Bombus s. str. supports additional species (Apidae, genus Bombus)

Figure 2. Estimate of phylogeny from MrBayes for the fast-evolving COI gene of Bombus s. str. as a metric tree from the longest examples of sampled unique COI-barcode haplotypes (from data for 559 sequences from Williams, Brown, et al. 2012), combined with the Bayesian Poisson-tree-process (PTP) solution with spots showing the nodes with the highest support for coalescents of candidate species by maximum likelihood (outgroup B. vagans not shown). Values above the nodes are MrBayes Bayesian posterior probabilities, showing branch support for groups; values below the nodes are PTP maximum-likelihood support values that all daughter haplotypes are parts of a single species. The scale bar is calibrated in substitutions per nucleotide site. Each sample sequence is labelled with: the sequence length in number of nucleotides; a taxon name, often referring to a particular colour pattern; a code that consists of a specimen identifier from the project database and a sequence identifier; followed with its geographic origin. Lineages with high probabilities of representing one or more candidate species in the PTP results are shown with thick lines and the most recent common ancestor of each candidate species (the species' coalescent) is shown with a black spot. The branches within the candidate species are shown with thin lines.