It was first described by James Bond and Rodolphe Meyer de Schauensee in 1939 from a specimen collected in Bolivia, and further birds that were described from Peru in 1971 were thought to be a new subspecies.

In 1937 while in Bolivia Mr M. A. Carriker found two birds, a male and female, which were in the cracid family.

[3] Although the consensus at the time of discovery for P. unicornis to be a species with two subspecies in the genus Pauxi, many different suggestions have been made since.

When Weske and Terborgh discovered the subspecies koepckeae they concluded pauxi and unicornis should be considered separate species.

[3][5] Additional studies by Gastañaga and coauthors in 2011 considered koepckeae to be a wholly distinct species on the basis of a somewhat smaller and more triangular crest and different vocalisations.

Just two years later Charles Vaurie opposed this 'lumping' of species and argued that Pauxi, Mitu, Crax and Nothocrax should each be their own genera.

[4] Not content with either of these two options Delacour and Amadon suggested that Pauxi and Mitu should indeed be grouped with Crax, but that Nothocrax was distinct enough to be its on genus.

The plumage is generally black, but lacks a blue sheen in primary feathers, and has a white belly, thigh tufts and under-tail coverts.