Systematics

There are currently two subspecies recognized under Tangara argyrofenges : T. a. argyrofenges and T. a. caeruleigularis (Dickinson and Christidis 2014):

The nominate subspecies, Tangara argyrofenges argyrofenges, is described in Detailed Description, and is found in the yungas among Andean slopes of Bolivia, specifically within the departments of La Paz, Cochabamba and Santa Cruz, and among the surrounding subtropical forests (Isler and Isler 1987, Wheatly 1995).

The second subspecies, Tangara argyrofenges caeruleigularis, is similar, but has a generally paler yellow tinge in comparison, and the throat is more blue than opalescent green (Hilty 2011). T. a. caeruleigularis is not found in Bolivia, but rather frequents areas in the extreme south of Ecuador as well as areas in Peru (Clements et al. 2013). Within Peru, T. a. caeruleigularis is found in northern Peru, within the Huayabamba Valley in subtropical zones (5,000 feet altitude) and in Central Peru within the Andean slopes of the Amazonas and San Martin (Paynter and Storer 1970, Isler and Isler 1987). T. a caeruleigularis has been found as far south as Conchapen Mt. in Junin, Peru (Wheatley 1995).

Tangara argyrofenges is a member of the speciose genus Tangara. This genus includes 49 species, more species than any other genus of exclusively neotropical birds (Isler and Isler 1987). Isler and Isler (1987) subdivided Tangara into 13 species groupings based on geographic range, appearance, behaviors (with an emphasis on foraging behaviors), vocalizations, and nest sites. Green-throated Tanager belongs to Isler and Isler’s species group 12, along with Black-capped Tanager (Tangara heinei), Silvery Tanager (Tangara viridicollis), Black-headed Tanager (Tangara cyanoptera), and Golden-collared Honeycreeper (Iridophanes pulcherrimus, but at the same classified as Tangara pulcherrima). Recent genetic studies have rejected the honeycreeper as a member of the genus Tangara (Burns et al. 2003) and place it in the genus Iridophanes. In addition, when Graves and Weske (1987) described Tangara phillipsi (Sira Tanager), they argued that it was part of a “black-capped” group that contained T. argyrofenges, T. heinei, and T. viridicollis. These four species form a superspecies complex (Graves and Weske 1987, Isler and Isler 1987). Burns et al. (2014) performed a comprehensive phylogenetic analysis of tanagers, using multiple genes. They found this group to be monophyletic, and T. viridicollis as the sister taxon to the remaining three species. However, they were unable to identify whether T. phillipsi or T. heinei is the closest relative to T. argyrofenges. These three species are one of a few groups of tanagers that were only weakly differentiated genetically when compared to other species (Burns et al. 2014). T. argyrofenges, T. phillipsi, and T. heinei were differentiated by an average of 0.34% (0.29-0.44%) sequence divergence; however, their well-differentiated plumage and geographic locations contrasts this, and allows for their classification as separate, allopatrically distributed species (Burns and Naoki 2004, Burns et al. 2014). This level of sequence divergence is consistent with the idea of late Pleistocene glacial cycles within the last 800,000 years in the Andes influencing speciation via allopatry for T. argyrofenges and T. heinei (Sedano and Burns 2010).