Description of Poecilia (Acanthophacelus) obscura n. sp., (Teleostei: Poeciliidae), a new guppy species from western Trinidad, with remarks on P. wingei and the status of the “Endler’s guppy”

Poecilia obscura, new species, is described from the Oropuche system, Trinidad. A mitochondrial DNA-sequence based molecular phylogenetic analysis revealed the status of the new species as a separate taxon. It is most closely related to the Common guppy, P. reticulata and to the recently described species, P. wingei. It can also be distinguished by morphometrics and gonopodial characteristics from these two species, although the ranges for all values overlap. A definition of the new species on morphology criteria alone is thus impossible. Therefore, P. obscura forms a cryptic species complex with the two other species. P. wingei is now unequivocally defined by the molecular phylogeny as a valid species. The three guppy species are included in the subgenus Acanthophacelus Eigenmann (1907), which is considered as generically different from all other taxa of the Poeciliinae sensu Parenti (1981).