Range extension of the Mexican-endemic killifish Profundulus chimalapensis (Cyprinodontiformes: Profundulidae), with comments on its phylogenetic placement and possible intergeneric hybridization with Tlaloc Álvarez & Carranza 1951.

Recent ichthyological surveys in southern Mexico resulted in the unexpected discovery of populations of P. chimalapensis outside its distribution range, broadening its extent of occurrence to a total of three river basins (Coatzacoalcos [original], Grijalva, Ostuta) and two versants (Atlantic [original] and Pacific). The taxonomic nature of these populations was further investigated using comparative genetic data in a phylogenetic framework.