This genus is distinguished from Ardetta by its longer bill, the culmen considerably exceeding the middle toe with its claw in length, the tarsus being slightly shorter still. The back of the neck is less conspicuously nude. The members of the present genus are considerably larger birds than Ardetta, and have very different plumage; but they are not, as is often stated, distinguished by having the tibia partly naked, for Ardetta cinnamomea resembles them in that respect. The generic name Ardeiralla, sometimes used for the Black Bittern, belongs to a very distinct form, peculiar to Africa.
Four species from the Oriental and Australian regions are referred to the genus Dupetor, but only one is Indian.