Monotypic (Hilty 2011).
Monotypic (Hilty 2011).
Merida Flowerpiercer (D. gloriosa) belongs to the tanager family Thraupidae, within the diverse subfamily Diglossinae. This subfamily consists of 64 species mostly found at high elevations (Burns et al. 2014). There are 14 genera in this subfamily, including Diglossa, which encompasses 18 species (Burns et al. 2014). Previous taxonomies classified Diglossa in Coerebidae (honeycreepers), Parulidae (New World warblers), or Emberizidae (American sparrows) (Burns et al. 2003); phylogenetic analysis of DNA sequence data, however, clearly indicates that Diglossa flowerpiercers are tanagers (Burns et al. 2014). Within tanagers, Catamenia (seedeaters) is sister to Diglossa (Burns et al. 2014).
Vuilleumier (1969) subdivided Diglossa into four species-groups based on physical characteristics; members of these groups also share habitat preference, social behavior, and feeding behavior (Isler and Isler 1987). Merida Flowerpiercer belongs to Vuilleumier's lafresnayii species-group (but see below), which also includes Glossy Flowerpiercer D. lafresnayii, Chestnut-bellied Flowerpiercer D. gloriosissima, Moustached Flowerpiercer D. mystacalis, D. gloriosa, Black Flowerpiercer D. humeralis, Black-throated Flowerpiercer D. brunneiventris, Gray-bellied Flowerpiercer D. carbonaria, and Scaled Flowerpiercer D. duidae (Vuilleumier 1969). Members of this group are aggressive towards other species and members of the same species (Isler and Isler 1987). Within the lafresnayii species-group, Vuilleumier (1969) recognized two superspecies, the lafresnayii superspecies and the carbonaria superspecies. Diglossa gloriosa belongs to the carbonaria superspecies, along with D. humeralis, D. carbonaria, and D. brunneiventris. Three of the remaining members of the lafresnayii species-group belong to the lafresnayii superspecies: D. lafresnayii, D. gloriosissima, and D. mystacalis; D. duidae was not assigned to a superspecies by Vuilleumier (1969).
Diglossa humeralis, D. gloriosa, and D. brunneiventris were considered subspecies of D. carbonaria by some authorities (e.g., Zimmer 1929, Storer 1970). Vuilleumier (1969) recognized two species in this complex, the primarily black D. humeralis, and the more patterned taxa (including gloriosa) as subspecies of D. carbonaria. Recognition of four species in this group is based on Graves (1982).
Two genetic studies have investigated relationships among flowerpiercers and included samples of D. gloriosa. Mauck and Burns (2009) sampled mtDNA data from all species of flowerpiercers. Burns et al. (2014) also sampled all species and included mtDNA data as well as some nuclear sequences from some species. Both studies found that the four members of the carbonaria superspecies form a monophyletic group. The amount of sequence divergence among the species within the carbonaria superspecies is much less than that found between most other avian species and is similar to the level seen within most species. However, the plumage patterns found within the carbonaria superspecies are the most variable of all flowerpiercer superspecies (Mauck and Burns 2009). Thus, the carbonaria superspecies represents a relatively recent radiation in which plumage has evolved rapidly. Phylogenetic analyses using BEAST indicate that the earliest node of the carbonaria superspecies group dates to 0.475 Mya (Mauck and Burns 2009). The Bayesian and likelihood trees of Mauck and Burns (2009) differ in their placement of species within the carbonaria superspecies complex. In the likelihood tree, D. gloriosa is the sister taxon to D. humeralis, whereas Bayesian analyses place D. gloriosa as the sister taxon to a clade containing all remaining species of the carbonaria superspecies (Mauck and Burns 2009). Burns et al. (2014) identify D. gloriosa as the sister taxon to D. humeralis, similar to the likelihood tree of Mauck and Burns (2009). However, there was no strong support for relationships within the carbonaria superspecies in any of these analyses. Thus, relationships within the carbonaria superspecies remain to be resolved. Although the carbonaria superspecies is monophyletic, members of the carbonaria superspecies are not closely related to the lafresnayii superspecies or to D. duidae. Thus, Vuilleumier’s (1969) lafresnayii species-group is not monophyletic and should not be recognized.