Phylogenetic tree of Middle American Rhamdia based on comparative COI sequence data, highlighting the phylogenetic position of individuals from the newly discovered hypogean populations as well as from epigean populations near the surveyed caves. Cave-dwelling species/populations in red (newfound in bold). Epigean species/populations in black, except for localities surveyed herein, in blue. Terminals corresponding to COI sequences obtained from GenBank (www.ncbi.nlm.nih.gov/Genbank), BOLD (www.barcodinglife.org), or from unpublished data previously generated by the senior author (JA), include the corresponding accession or voucher/catalog number in the label (between the species name and the country of origin). Colored circles on nodes indicate degree of clade support as determined by bootstrap values (B).