The most extraordinary feature is unquestionably the former existence of the gigantic Dinornithes or moas and, another family of Ratitae, the weird-looking kiwis or Apteryges, which are totally unlike any other existing birds.
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.
Further, it is the opinion of competent ornithologists that there is affinity of the Australian emeus and cassowaries with the New Zealand moas and with the Malagasy Aepyornis.
In the North Island the moas seem to have died out soon after the arrival of the Maoris, according to F.
The most striking feature of the moas, besides the truly gigantic size of some species, is the almost complete absence of the wings.
In conformity with these reductions the breastbone of the moas is devoid of any coracoidal facets; there is no trace of a keel, and the number of sternal ribs is reduced to three or even two pairs.
The hind limbs are very strong; the massive femur has a large pneumatic foramen; the tibia has a bony bridge on the anterior surface of the lower portion, a character in which the moas agree only with Apteryx amongst the other Ratitae.
Another important point, in which the moas agree with the other Ratitae and differ from the kiwis, are the branched, instead of simple, porous canals in the eggshell.
The affinities of the moas are undoubtedly with the Australian Ratitae, and, in spite of the differences mentioned above, with the kiwis.
The relationship with Aepyornis of Madagascar is still problematic. Whilst the moas seem to have been entirely herbivorous, feeding not unlikely upon the shoots of ferns, the kiwis have become highly specialized wormeaters.
Unmolested by enemies (Harpagornis, a tremendous bird of prey, died out with the Pleistocene), living in an equable insular climate, with abundant vegetation, the moas flourished and seem to have reached their greatest development in specialization, numbers, and a bewildering variety of large and small kinds, within quite recent times.
Unfortunately no fossil moas, older than the Pleiocene, are known.
The moas ranged in size from that of a turkey to truly colossal dimensions, the giant being Dinornis maximus, which, with a tibial length of 39 in., stood with its small head about 12 ft.
Owen, approximating more closely than any other living birds to the extinct moas of New Zealand.