Systematics

Monotypic.

Described as Poospiza caesar Sclater and Salvin 1869, with a type locality of Tinta, Cuzco, Peru.

This species long was classified in the monotypic genus Poospizopsis Berlepsch 1893 (e.g. Hellmayr 1938, Meyer de Schauensee 1966). Meyer de Schauensee (1966) suggested that caesar possibly was better included within Poospiza; Paynter (1970) and subsequent authors adopted this suggestion. A phylogenetic survey of Poospiza, based on an analysis of mitochondrial DNA sequence data, confirms the inclusion of caesar in Poospiza (Lougheed et al. 2000). This survey included only 9 out of the 15 species of Poospiza, however, so the affinities of caesar within Poospiza are not fully resolved; in this study, caesar was sister to Poospiza hypochondria (Rufous-sided Warbling-Finch) (Lougheed et al. 2000).

Poospiza traditionally was classified in a family of finches, such as Fringillidae (Hellmayr 1938) or Emberizidae (Paynter 1970, Dickinson 2003). Phylogenetic analysis of DNA sequence data, from both mitochondrial and nuclear genes, indicates however that Poospiza is embedded within Thraupidae (tanagers and allies) (Lougheed et al. 2000, Burns et al. 2002, 2003, Klicka et al. 2007). The position of Poospiza within this clade in not yet fully resolved, but the available evidence suggests that Poospiza is related to Thlypopsis, Pyrrhocoma, Cypsnagra, Nephelornis, and some members of Hemispingus (Burns et al. 2002, 2003, Klicka et al. 2007).