No true casque, but the basal portion of the upper mandible is thickened and crossed at the sides by dark oblique grooves not extending across the culmen, wanting in the young and increasing in number with age; cheeks, chin, and throat naked; tail long and graduated. Feathers of head and neck loose-textured, both shafts and webs hair-like. Commissure of the bill greatly broken away in adults. Coloration of sexes different.
A single species.