Species of the Poecilia sphenops complex (Pisces: Poeciliidae) in México

" Poecilia sphenops alternately has been cast as several (or many) species, or as a single polytypic species. Laboratory, field, and morphological evidence gathered mainly from a mixed population of mollies in southern Mexico, but also from other parts of Mexico and Guatemala, indicates that "Poecilia sphenops" is not a single species but a complex of unknown magnitude. The name Poecilia butleri is resurrected from synonymy for the Pacific representative of P. mexicana in Mexico and southern Guatemala. A natural hybrid between P. sphenops and P. butleri is described "