The cone-billed tanager (Conothraupis mesoleuca) is a species of bird in the family Thraupidae.It is endemic to Brazil. It was described on the basis of a single male specimen collected in Mato Grosso, Brazil, in 1938. No other individuals were collected or seen and some feared the bird had become extinct, while others speculated that it possibly only was an aberrant black-and-white tanager (unlikely, as the black-and-white tanager only occurs far from the region where the cone-billed was collected). In 2003, it was rediscovered by D. Buzzetti in gallery woodland and Cerrado in the Emas National Park, only to be independently rediscovered at the same locality in 2004 by B. A. Carlos.