Mitochondrial and nuclear phylogenies of all 26 Xiphophorus species. The phylogenetic trees were constructed from (a) combined sequences of two mtDNA loci (1239 bp) (complete control region and a segment of the cytochrome b gene) and (b) combined sequences of eleven nuclear loci (7276 bp). We indicate with (*) and (#) the supporting values of monophyly and paraphyly of the southern swordtails respectively. Numbers indicate Bayesian posterior probabilities, Maximum-Likelihood, Neighbor-Joining and Maximum-Parsimony bootstrap values, respectively. The values of the branch length that was truncated are 0.447 (a) and 0.038 (b). The two hybrid origin species – Xiphophorus monticolus, one of the four newly described species, and X. clemenciae are highlighted in red and the three remaining new species, X. mixei, X. kallmani and X. mayae in blue. Some fish images were obtained from the Xiphophorus Genetic Stock Center (Texas) with permission.