Systematics

Not known for this species; due to its very limited range (eastern Honduras and northwestern Nicaragua), geographic variation not likely, although Newell et al. (2007) note a consistent 2 mm difference in wing cord between birds measured in NP La Tigra, Honduras and measurements given by Ridgway (1911) for a Nicaraguan population.

Traditionally considered to be closely related to the Green-throated Mountain-gem (Lampornis viridipallens); suggested by Cha (1999) to form a superspecies with viridipallens. Garcia-Moreno et al. (2006) examined the phylogenetics of the genus Lampornis based on DNA sequence data. They confirmed the monophyly of the genus Lampornis, if the White-bellied Mountain-gem (Lampornis hemileucus) is removed from the genus (but see McGuire et al. 2008). Otherwise Garcia-Moreno et al. (2006) were not able to fully resolve relationships with the genus, although they identified two clear subunits within the Central American species of Lampornis. The northern group contains sybillae and viridipallens; the southern group contained calolaema and castaneoventris (including cinereicauda).