Uncoupled histories in the largest continental arc of North America: goodeid fishes and their gyrodactylid parasites influenced differently by the Trans-Mexican Volcanic Belt

Considering TMVB emergence powerfully influenced goodeid diversification and distribution, we assessed whether it also affected Gyrodactylus lineages associated with these nearctic hosts. Previously, six Gyrodactylus spp. were known to infect goodeids (Goodea atripinnis, Giradinichthys multiradiatus) within and north of the TMVB; we recorded six gyrodactylids (two known, four undescribed species) infecting Ilyodon and Allotoca spp. south of the TMVB (S-TMVB).

Using phylogenetic (internal transcribed spacer, cytochrome oxidase subunit II) and species delimitation (ASAP, MSC models) analyses, we tested three hypotheses: 1) ancient parasite lineages whose association with goodeids probably predates TMVB emergence occur both sides of this barrier; 2) following TMVB emergence, some nearctic gyrodactylids will only be found S-TMVB; 3) gyrodactylids infecting goodeids S-TMVB switched hosts from other Cyprinodontiformes.