The Amethyst-throated Sunangel includes six subspecies, which differ subtly in the color of the gorget and the color of the forecrown. The taxonomy of these six subspecies has been complicated, with anywhere from one to three species recognized in this group. In brief, there is a group of three northern subspecies, in the Andes of northeastern Colombia and in Venezuela; and a very disjunct group of three southern subspecies, that occur from southern Ecuador south to Bolivia. The three northern subspecies sometimes are classified as a separate subspecies, Longuemare's Sunangel (Heliangelus clarisse); or some authors separate the population endemic to Venezueala as a separate species, Merida Sunangel (Heliangelus spencei). Features that are shared by all members of this group are the purple gorget in the male, and a conspicuous white or buffywhite crescent across the breast in both sexes. The throat of the female typically is dull brown (clarisse group) or rufous brown (southern amethysticollis group), but in some populations, especially in subspecies laticlavius of southern Ecuador and northern Peru, the female may have a purple gorget, similar to but smaller than that of the male. The Amethyst-throated Sunangel typically is a common species, and occupies humid forest and forest edges in montane evergreen forest.