Most male euphonias are dark metallic blue above and bright yellow below.

[3] A molecular phylogenetic study of the finch family Fringillidae published in 2012 included 9 species from the genus Euphonia and a single species from the genus Chlorophonia, the blue-naped chlorophonia.

[5][6] A taxonomic analysis published in 2020 found that the genus Euphonia was paraphyletic with respect to Chlorophonia.

To resolve the paraphyly the authors of the study proposed the resurrection of the genus Cyanophonia that had been introduced in 1851 by Charles Lucien Bonaparte.

An alternative and simpler way to resolve the paraphyly would be move the three species from Euphonia into Chlorophonia, which has been followed by the IOC.