Phylogenetic tree for R. sanguineus based on partial COI gene sequences. Phylogenetic tree based on partial COI gene sequences of R. sanguineus was constructed using the neighbor-joining method with Kimura two-parameter analysis and bootstrap analysis of 1000 replicates. The numbers on the branches indicate the percentage of replicates that reproduced the topology for each clad. The green rhombi indicate the sequences acquired from the current study (Ascaris suum was used as an outgroup).