The genus Dryotriorchis is possible monotypic taxon with a single species - Congo serpent eagle
The Congo serpent eagle (Circaetus spectabilis) is a species of bird of prey in the family Accipitridae, and is sometimes placed in the monotypic genus Dryotriorchis by some taxonomic authorities. This species is distributed across the African tropical rainforest, including upper and lower Guinean forests. This serpent eagle specializes in hunting in these forests’ dark understories. It has two subspecies, the nominate subspecies Dryotriorchis spectabilis spectabilis and Dryotriorchis spectabilis batesi. Though monotypic, it appears to be very closely related to Circaetus. This hawk is a medium-sized bird with distinctive short, rounded wings and a long, rounded tail. It is varying shades of brown on its back and has a slight crest. Its breast is white with variable amounts of a rufous wash and, in the nominate subspecies, is covered in round, blackish spots. The subspecies D. s. batesi only has these dots on its flanks. The Congo serpent eagle closely resembles Cassin's hawk-eagle, and some ornithologists believe that this likeness is a rare example of avian mimicry. It is a very vocal raptor, and often is one of the most heard species in its habitat.
The Congo serpent eagle lives in southern Sierra Leone and Guinea, Liberia, and southern Côte d'Ivoire and Ghana. It is also found in southern Nigeria and the Central African Republic south through northern and eastern Democratic Republic of the Congo in the east and through Gabon into the northern Republic of the Congo in the west with an isolated population in northern Angola. D. s. spectabilis is found in upper Guinean forests from Liberia to northern Cameroon, while D. s. batesi is found in lower Guinean forests from southern Cameroon through Gabon and western Uganda. Its range covers 2,880,000 square kilometers (1,110,000 sq mi). The species lives in dense primary forest below 900 meters (3,000 ft) in elevation in the dark understory. As it is adapted for dense forest, it is not well-adapted for secondary forests and plantations. The Congo serpent eagle does not migrate, though it is unknown if it is locally nomadic.