Crax is a genus of curassows in the order Galliformes, a clade of large, heavy-bodied, ground-feeding birds. They are known from tropical South America with one species, the great curassow, ranging northwards through Central America as far as Mexico. The currasows in this genus are noted for their sexual dimorphism; males are more boldly coloured than females and have facial ornamentation such as knobs and wattles. They are also characterised by curly crests and contrastingly-coloured crissums (the area around the vent). Crax curassows probably originated as a distinct lineage during the Late Miocene. During the Messinian, the ancestral Crax split into two lineages separated by the Colombian Andes and the Cordillera de Mérida which uplifted at that time. The northern lineage radiated into