Phylogenetic tree of 90 COI sequences of three Oswaldocruzia species reconstructed by Bayesian inference. The tree is based on a 370 bp-long alignment and rooted using Ancylostoma tubaeforme and A. ceylanicum as the outgroup. Each Oswaldocruzia filiformis represents a unique haplotype. Haplotype numbers correspond to those in Figure 4 and Supplementary Table S1. Values at the nodes indicate posterior probabilities (>70) from the Bayesian inference, and bootstrap values (>50) from the maximum likelihood analysis. Lower values are shown as dashes (–). The length of branches represents the number of substitutions per site. The sequences retrieved from GenBank are greyed.