Systematics

Three subspecies recognized (Weller 1999, Dickinson and Remsen 2013):

guatemalae, described as Saucerottea cyanura gautemalæ [sic] (Dearborn 1907); type locality Mazatenango, Guatemala

Occurs in southern Mexico and in Guatemala.

Similar to nominate cyanura, but "much darker in color, especially the wings; primaries blue-black instead of violet-dusky; chestnut on basal portion of remiges darker amd more restricted; green of upper parts darker, and blue of tail more violaceous, especially on basal portion of outer webs of rectrices, where the color sometimes inclines to metallic purple, the under tail-coverts almost wholly blue-black or dark steel blue, or else margined with darker grayish or chestnut" (Ridgway 1911: 446).

cyanura, described as Amazilia cyanura Gould 1859; type locality Realejo, Nicaragua.

Occurs in El Salvador, Honduras, and Nicaragua.

See Detailed Description.

impatiens, described as Saucerottea cyanura impatiens (Bangs 1906); type locality San Pedro, Costa Rica.

Occurs in northwestern Costa Rica.

Similar to nominate cyanura, but "larger with shorter bill; head, back and breast darker green; under tail coverts dull steel blue edged with rich ferruginous - the under tail coverts in true S. cyanura are edged with pale grayish" (Bangs 1906: 105); also has "extended rufous in wings" (Weller 1999: 604).

Subspecies impatiens was not recognized by Peters (1945), but Weller (1999) considered it a valid taxon.

Phylogenetic analysis of DNA sequence data 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); Amazilia belongs to the emerald clade.

Phylogenetic analysis of DNA sequence data, from both mitochondrial and nuclear genes, indicates that the diverse and specioise genus Amazilia is polyphyletic, as the genera Hylocharis, Chrysuronia, Lepidopyga, and Damophila are embedded within the current Amazilia (McGuire et al. 2007, 2009). There is no comprehensive phylogenetic survey, however, of Amazilia. Weller (1999) placed cyanura in the genus Saucerottia. McGuire et al. (2007, 2009) did not include cyanura in their study, although the genus Saucerottia (sensu Weller) was represented by two other species, Amazilia saucerrottei (Steely-vented Emerald) and Amazilia viridigaster Green-bellied Hummingbird), which were sisters (McGuire et al. 2007, 2009).

Dickey and van Rossem (1938: 263) reported extensive hybridization in El Salvador between Amazilia beryllina devillei (Berylline Hummingbird) and Amazilia cyanura cyanura. These two species also are broadly sympatric in Honduras, where Monroe (1968) found no evidence of hybridization. Weller (1999) regarded Dickey and van Rossem's report of hybridization as "unproven, and may be erroneously based on variable tail coloration" of devillei, but did not discuss these specimens in greater detail. Weller (1999) also considered beryllina and cyanura to form a superspecies.