Principal component analyses of monogenean flatworms infecting chromidotilapiine cichlids. A, Species of Onchobdella showing three distinct clusters that are mostly congruent with the species identities assigned in this study. B, Several species of Cichlidogyrus strongly resemble C. tilapiae, but at least two of them form distinct species. C, Species of Cichlidogyrus infecting chromidotilapiine cichlids form distinct clusters in the PCA, albeit with some overlap.