Green-fronted Hummingbird (Agyrtria viridifrons) - HBW 5, p. 599

Taxonomy: Cyanomyia viridifrons Elliot, 1871, Putla de Guerrero, Mexico.
Genus usually merged into Amazilia. Forms a superspecies with A. violiceps. Until mid-20th century, holotype of present species was believed to represent an aberrant individual of A. violiceps, due to sexual and age-related variation in coloration of crown in both species; in addition, forms described as “Cyanomyia guerrerensis”, “Uranomitra derneddei” and “U. atricapilla” all refer to present species but were earlier considered synonyms of A. violiceps; when finally recognized as a valid taxon, present species was considered a race of A. violiceps; recent morphological and biogeographical studies, however, including discovery of zone of sympatry in Guerrero but no known hybridization, confirm validity of present species. Race wagneri sometimes considered a separate species, but morphological differences slight. Birds from C Oaxaca have been awarded race rowleyi, but probably not valid, due to strong intergradation of nominate and race wagneri in zone of supposed secondary contact. Nominate race shows disjunct distribution, with gap in E Oaxaca. Two subspecies recognized.