(syn. Hieraaetus Ϯ Ayres's Hawk Eagle H. ayresii) Gr. ανωμαλος anōmalos anomalous < negative prefix αν- an- ; ομαλος omalos even; αετος aetos eagle; "Another bird, Spizaetus ayresi Gurney (Ibis, 1862, p. 149) has until recently been confused either with Nisaetus spilogaster or Lophaetus occipitalis (cf. Finch-Davies, Ibis, 1919, p. 167, Pl. III); but it is obvious that it cannot be referred to any of the genera of small eagles, and I therefore propose to place it in a new genus, ANOMALAETUS, characterised by having the colour markings of the wing and tail quills as in Lophoaetus, but with a shorter and broader crest, with the short tarsus of Micraetus and in the adult plumage broadly marked below with black on a white ground, much after the fashion of N. spilogaster; in the immature plumage the underparts of the body are plain, as in Micraetus. Nisaetus has long legs and no crest." (A. Roberts 1922).