Ratites

(vertebrate zoology) A group of flightless, mostly large, running birds comprising several orders and including the emus, cassowaries, kiwis, and ostriches.

A group of flightless (except for tinamous), mostly large, running birds formerly segregated as a superorder of birds, the Palaeognathae, but whose interrelationships have been a long-standing controversy. The ratites represent two or three phyletic lines (the emus, cassowaries, moos and kiwis, ostriches and elephant birds, and rheas and tinamous—the last two groups may be very closely related) which evolved from a common ancestral stock, possibly much like the still volant tinamous of Central and South America. See also Aves; Neognathae; Struthioniformes.