Rhea (bird) males of "R. americana" can reach tall at the head, at the back and can weigh up to , The lesser rhea is somewhat smaller as they are only tall at the back. Their wings are large for a flightless bird () and are spread while running, to act like sails. Unlike most birds, rheas have only three toes. Their tarsus has 18 to 22 horizontal plates on the front of it. They also store urine separately in an expansion of the cloaca. Rheas are from South America only and are limited within the continent to Argentina, Bolivia, Brazil, Chile,
New Guinea flightless rail and diverged strongly in some aspects, while otherwise adapting in similar ways. New Guinea flightless rail The New Guinea flightless rail ("Megacrex inepta"), also known as the Papuan flightless rail, is a species of bird in the family Rallidae, in the monotypic genus "Megacrex". Sometimes however, it was included in "Amaurornis" or "Habroptila", but this is incorrect. It is found in Indonesia and Papua New Guinea. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical mangrove forests, and subtropical or tropical swamps. It is threatened by habitat loss. "M. inepta" is indeed closely related to "Amaurornis",