There are two subspecies: Psophia crepitans crepitans and P. c. napensis. These races differ only slightly in plumage: the race napensis has solely bronzy or purple iridescence (green or violet present in crepitans) on the lower neck, more ferruginous coloration on the upper back, and a lighter grey hind-wing patch than crepitans.
Psophia crepitans crepitans Linnaeus, 1758
Found from southeastern Colombia in Meta (except for the Cerro Macarena area) east through southern and eastern Venezuela, mostly south of the Orinoco, but north in the states of Sucre and Monagas, to northern Brazil (west of the Rio Negro), Guyana, French Guiana and Suriname (Blake 1977). Characters as described above in Detailed Appearance.
Psophia crepitans napensis Sclater and Salvin, 1873
Occurs in southeastern Colombia (north to the Cerro Macarena region in southwestern Meta) south through eastern Ecuador to eastern Peru, north of the Río Marañón and Amazon), and east to from extreme northwestern Brazil north of the Río Solimões (Blake 1977). Similar to nominate crepitans, but the lower foreneck and the chest are bronzy purplish, lacking green or violet reflections; the upperparts are more extensively ferruginous; and the gray of the wings is paler and clearer (Blake 1977).
The Trumpeter family (Psophiidae) is quite small, with only three species (Dark-winged, Pale-winged, and Gray-winged trumpeters) in a single genus Psophia.
Sherman (1996) proposed the following scenario of the speciation of modern trumpeter species. The three extant species of trumpeter probably evolved from single species with a continuous range in the Pliocene. With the advent of glaciation in the Pleistocene, tropical rainforests underwent a series of contractions, and tropical lowland rainforest was for periods confined to isolated patches, or refugia, surrounded by a dry savanna. Trumpeter populations were likely confined to different refugia and diverged into separate species, and further genetic isolation was imposed by the growth of size of the Amazon river as rainfall increased. Thus extant but spatially separate trumpeters likely evolved from allopatric speciation following a series of vicariance events.
Zimmer (1930) suggested that all populations of trumpeters belonged to a single species (Psophia crepitans). Most authorities recognize a minimum of three species, however, in part because the distributions of nominate crepitans and of Psophia leucoptera ochroptera appear to approach one another near the Rio Negro in north central Brazil (Hellmayr and Conover 1942: 312).