So far, with the present list of tested taxa,
this living bird (Fig. 1) is the seemingly unchanged descendant of all living birds, other than the ratites and kiwis, according to the large reptile tree (LRT, 1089 taxa). Megapodius demonstrates that early neognaths, like their sister paleognaths, were long-legged terrestrial omnivores, able to fly, but not very well, despite the large and subdivided breastbone (keeled sternum) and long locked-down coracoids.
Megapodius freycinet (Gaimard 1823) is the extant dusky scrubfowl, one of the most primitive of living neognath birds. This one nests at the base of the hook-beak predatory birds, the most basal extant neognaths.
Gaimard JP 1823. Mémoire sur un nouveau genre de Gallinacés, establi sous le nom de Mégapode. Bulletin General et Universel des Annonces et de Nouvelles Scientifiques 2: 450-451.