Three subspecies currently recognized:
pectoralis (Salvin 1891); type locality Costa Rica
Occurs in Nicaragua and in northwestern Costa Rica. Similar to calolaemus but gorget of male is deeper purple; otherwise "nearest in color to ... homogenes, but breast with the green restricted, the lower area darker, near hair brown, under tail coverts darker, and green of foreneck and upper tail coverts decidedly darker" (Wetmore 1967, 1968).
calolaemus (Salvin 1865); type locality Volcán de Cartago (Volcán de Irazú, Costa Rica)
Occurs in northern and central Costa Rica.
See Detailed Description.
homogenes Wetmore 1967; type locality Chitra, Veraguas, Panama
Occurs in southwestern Costa Rica and western Panama. Male similar to nominate calolaemus, but breast and abdomen darker gray. Underparts of female darker, more rufous, and upperparts darker, more bluish green; central rectrices darker bronze-green; white-tipping on outer rectrices reduced; and bluish black subterminal band broader (Wetmore 1967).
There is significant geographic variation, primarily in male plumage, in Lampornis hummingbirds between Nicaragua and Panama. Briefly, there are three groups of mountain-gems in this region: birds with white throats and gray tails (cinereicauda); birds with purple throats and blue tails (pectoralis, calolaemus, and homogenes); and birds with white throats and blue tails (castaneoventris). These variably have been recognized as a single, highly variable species (e.g. Peters 1945, Wetmore 1967, Wetmore 1968, Schuchmann 1999), or as two species, one purple-throated (Purple-throated Mountain-gem Lampornis calolaemus) and one white-throated (White-throated Mountain-gem Lampornis castaneoventris) (e.g., American Ornithologists' Union 1983, 1998). Note that the distribution of Lampornis castaneoventris is geographically between that of the two western subspecies of Lampornis calolaemus (pectoralis, calolaemus) and of the eastern subspecies (homogenes). Another alternative is to recognize castaneoventris (monotypic), cinereicauda, and calolaemus as separate species (Stiles and Skutch 1989). Hybridization is reported between these groups where the ranges abut, but hydridization apparently is limited (Stiles and Skutch 1989) and some reports of hybridization may be based on mis-interpretations of the plumages of immature males (Schuchmann 1999).