Phylogenetic relationships within the aplocheiloid fish genus Rivulus (Cyprinodontiformes, Rivulidae): implications for Caribbean and Central American biogeography

We examined the phylogenetic relationships of 16 northern species of theaplocheiloid genus Rivulus inhabiting the Caribbean, Central America, andSouth America. A total of 714 base pairs per taxon were sequenced from twosegments of the mitochondrial genome, 12S rRNA and cytochrome b. Bothparsimony and neighbor-joining analyses suggest an ancient vicariant originof the Greater Antillean taxa, in addition to a quite recent dispersal ofspecies into the Lesser Antilles from the South American mainland. Combinedanalyses support the monophyly of the northern South American assemblage asthe sister group of a Central American/Columbian biota. However, themonophyly of the Central American biota remains uncertain. Divergenceestimates for the Central American taxa are calibrated from the LastCretaceous separation of the proto-Antilles from the Americas. These datasuggest that the extant Central American taxa represent the descendants ofat least two separate invasions during the Cenozoic, prior to the closingof the Panamanian isthmus. Times are consistent with the extensive evidencefor reptilian and mammalian exchange throughout the Cenozoic.