Aptornis defossor (Owen 1844; 80 cm in length) is the extinct flightless adzebill from New Caledonia. Here it is related to the New Zealand moa, Dinornis. Both are derived from the tropical hoatzin, Opisthocomus. The rostrum is sharp, short and turns down. The hind limbs and pelvis are robust. The wings are vestiges. The sternum is reduced.

Owen R 1844. On Dinornis, an extinct genus of tridactyle struthious birds, with descriptions of portions of the skeleton of five species which formerly existed in New Zealand. (Part I.) Transactions of the Zoological Society of London, 3(3): 235–275.

wiki/Adzebil_Aptornis