The Giant Bird Diatryma 



By WALTER GRANGER, American Museum of Natural History 



A REMARKABLE new bird has been added recently to the ancient 

 avifauna of North America*. This bird Hved in the Rocky Mountain 

 region during Eocene time, some 3,000,000 years ago, and was a con- 

 temporary of the little four-toed horse Eohippus. It is distinguished as being 

 the largest bird, so far as known, which has ever lived north of the Isthmus of 

 Panama, being excelled in size, in the Western Hemisphere, only by the great 

 Phororhachos of the more recent Miocene deposits of Patagonia. 



Fossil remains of birds are rare as compared with those of fish, reptiles, and 

 mammals, and consequently our knowledge of the past history, or evolution, 

 of the various groups of birds is meager. The reason for the scarcity of bird 

 fossils is partly because of the extremely delicate character of the bones, which 

 are usually the only parts of a vertebrate animal to be preserved ; also because 

 the habits of birds are such as to prevent them from becoming entombed in 

 the sands and muds and thereby becoming fossils of a later time; a third reason 

 is that the bodies of dead birds are apt to be devoured by animals, insects, or 

 by other birds. 



The oldest and most important fossil bird known is the ArchcBopteryx from 

 the Jurassic limestones of Bavaria, represented by two specimens which show 

 not only the bones but the impressions of the larger feathers. From the Pleis- 

 tocene of New Zealand come the great flightless Moas, the tallest birds 

 known, and from Patagonia the Phororhachos, also without power of 

 flight. Our own country has made a notable contribution to ancient ornithology 

 in its toothed birds — Hesperornis and Ichthyornis — from the Cretaceous chalks 

 of western Kansas. Scattered and fragmentary remains of other and more 

 modern birds from time to time have been collected in our western fossil 

 fields; often the specimens consisted of a single wing- or leg-bone or a part of a 

 foot, almost never was there enough of the skeleton to determine the exact 

 relationship to modern birds. It was a matter of unusual interest then when a 

 nearly complete and well-preserved skeleton of the gigantic Diatryma was dis- 

 covered last summer. 



The presence of a great bird in North America in Eocene times was known as 

 far back as 1876 when Professor Cope of Philadelphia published an account of 

 some fragments of a foot which he had found in northern New Mexico two 

 years before and to which he gave the name Diatryma gigantea. Nearly twenty 

 years later Professor Marsh of Yale described a single toe-bone of a gigantic 

 bird from the Eocene parts of southern New Jersey. He named this Barornis 

 but the bone cannot be distinguished from the corresponding bone of Cope's 

 genus. Nothing more was known of this bird until 191 1 when the writer found 

 in the Bighorn Basin, Wyo., in rocks of the same age as those in New Mexico, 



*See article in the Bulletin of the American Museum of Natural History, Vol. XXXVII, Art. XI 

 by W. D. Matthew and Walter Granger. 



(193) 



