The Sao Tome Grosbeak Neospiza concolor, endemic to the island of Sao Tome (Gulf of Guinea), is one of the least known birds in the world. Formerly considered to be an aberrant weaver (Ploceidae), it is currently placed in a monotypic genus within the true finches (Fringillidae). Phylogenetic inference based on mitochondrial and nuclear sequences confidently identifies N. concolor as an Old World finch (Fringillidae: Carduelinae) within the Crithagra seedeater/canary clade. The Sao Tome Grosbeak is therefore the world's largest canary, 50% heavier than the next largest species, and it co-occurs with a population of its sister species, the Principe Seedeater Crithagra rufobrunnea.