What is "razor-billed curassow"

The razor-billed curassow (Mitu tuberosum) is a species of bird in the family Cracidae. It is found throughout a large part of the Amazon Rainforest, though largely restricted to regions south of the Amazon River. Unlike other members of the genus Mitu, its crissum is deep chestnut and the tail-tip is white. The razor-billed curassow was formerly treated as a subspecies of Mitu mitu, but today this scientific name is restricted to the extremely rare Alagoas curassow.