Bill rather small, the edge of the upper mandible almost or quite straight; nostrils oval, nearly round, oblique; wing long, 5th quill longest, the feathers broad ; tail long, slightly rounded ; tarsus feathered. The foot is very remarkable : the toes are short, the inner toe thicker than the middle toe and nearly as long; outer toe very short; all the claws much less curved than in other Eagles, and the inner claw longest, longer even than the hind claw. Plumage in adults black throughout.
The generic name Neopus, used generally for this Eagle, was published in 1844 (Gray's Zool. Misc. p. 81), whilst Jerdon's name Ictinaetus dates from a year earlier, having been published by Blyth (J. A. S. B. xii, p. 128) in a note to the paper in which Hodgson gave the name Heteropus, which had to be discarded on account of previous use (Ibis, 1894, p. 289).
A single species.