Heterophallus

Heterophallus is a genus of small poeciliids found near the coast in calm waters of river basins in southeastern Mexico.

Species
There are currently two or three recognized species in this genus:
 * Heterophallus echeagarayi (Álvarez, 1952) (Maya gambusia)
 * Heterophallus milleri Radda, 1987 (Grijalva gambusia)
 * Heterophallus rachovii Regan, 1914 (Coatzacoalcos gambusia)

FishBase places Heterophallus echeagarayi in the genus Gambusia.