A y es Carinatae terrestres.
At any rate we begin to see that some of the Ratitae, namely the Rheidae, may possibly be an early and then much modified offshoot of such of the Carinatae as are now represented by the Crypturi, whilst in another part of the world, and at a much later time, kiwis and moas have sprung from a somewhat more Gallilorm stock, which points to a descent from a still undivided GalliformTinamiform mass.
A y es Carinatae aereae.
The separation of the Ratitae from the other birds, and their seemingly fundamental differences, notably the absence of the keel and of the power of flight, induced certain authors to go so far as to derive the Ratitae from the Dinosaurian reptiles, whilst Archaeopteryx (q.v.) and the Carinatae were supposed to have sprung from some Pterosaurian or similar reptilian stock.
We restrict the origin of the Ratitae to that great branch of still primitive Carinatae which, after separation of the Ratitae, has further developed into the legion of the Alectoromorphae, notably Tinamiand Galliformes, together with still low Gruiformes (see BIRD, Classification).
A y es Carinatae aquaticae.