Systematics

Opisthoprora euryptera is monotypic. There may be undescribed clinal geographic variation, however; Gary Graves noted that "southern birds [were] quite grayish" (Fjeldså and Krabbe 1990).

Described as Trochilus eurypterus (Loddiges 1832), with type locality Popoyán, Colombia. The genus Opisthoprora was proposed by Cabanis and Heine in 1860, with Trochilus eurypturus Loddiges as the type species.

A recent phylogenetic survey of the phylogenetic relationships of hummingbirds, based on DNA sequence data from both mitochondrial and nuclear genes, reveals that hummingbirds (Trochilidae) constitute nine major clades, comprising the hermits, mangos, Patagona, topazes, coquettes, brilliants, mountain-gems, bees, and emeralds (McGuire et al. 2007, 2009). Opisthoprora is a member of the coquette clade (McGuire et al. 2009). Genera that are documented as belonging to the coquette clade are Adelomyia, Aglaiocercus, Chalcostigma, Discosura, Heliangelus, Lesbia, Lophornis, Metallura, Oreonympha, Oreotrochilus, Oxypogon, Phlogophilus, Ramphomicron, and Sephanoides (McGuire et al. 2007, 2009). Additional genera that probably belong to the coquette clade are Polyonymus, Sappho, and Taphrolesbia (McGuire et al. 2009). The relationships of Opisthoprora within the coquette clade are not fully resolved, but it appears to belong to a group that also includes Oreotrochilus, Ramphotrigon, Lesbia, Oxypogon, Oreonympha, Chalcostigma, and Metallura (McGuire et al. 2009).