Fig. 130.—A †chalicothere (†Moropus elatus) of the lower Miocene. Restored from a skeleton in the Carnegie Museum, Pittsburgh.
Even more numerous and varied were the Artiodactyla. Peccaries of a primitive sort were common, and we find the last of the series of “†giant pigs,” which had been a very conspicuous group throughout the Oligocene. The lower Miocene genus, †Dinohyus, was a monstrous beast, six feet or more in height, with formidable canine tusks and a very long head made grotesque by bony excrescences upon the skull and jaws. For a pig, the legs were very long and the feet slender, having but two toes. The †oreodonts were present in great numbers, both small and large forms; except for bodily stature and modifications of the head, they all looked very much alike; †Merycochœrus, with its incipient proboscis, here made its first appearance. The last representatives of a family (†Hypertragulidæ) of small and graceful artiodactyls are found in this formation. One of these (†Syndyoceras, see [Fig. 215, p. 403]), an animal considerably larger than the existing Musk-Deer, was in its way even more bizarre-looking than the †chalicotheres; with an antelope-like head, it had four horns, one pair over the eyes, curving inward, and a shorter pair, with outward curvature, on the muzzle. Another genus (†Hypertragulus) was very much smaller and very slender.
The camels were beginning to diversify and give rise to several phyla. One of the genera (†Protomeryx), which did not much exceed a sheep in size, probably represented the main stock, which led to the camels and llamas of to-day. A second (†Stenomylus) was a still smaller animal, with remarkably long and slender legs, and might be called a “gazelle-camel,” while a third (†Oxydactylus, see [Fig. 209, p. 392]), which was larger and apparently the beginning of the †giraffe-camels, was noteworthy for its long neck. All of these lower Miocene camels had deer-like hoofs, the characteristic pad or cushion which gives such an exceptional appearance to the feet of modern llamas and camels not being fully developed till a later period. A very important new element in the North American fauna was the appearance of the first deer (†Blastomeryx), which came in the latter part of the Arikaree stage and were the forerunners of a renewed immigration from the Old World, which had been broken off during the upper Oligocene. This, however, is a disputed point; Professor Osborn and Dr. Matthew believe that these animals were truly indigenous and derived from a long line of American ancestry. The same genus continued through the middle Miocene, as we have already seen, and therefore no further description of it is called for.
The limits of the South American Miocene are very doubtful. The Paraná formation, here regarded as lower Pliocene, may prove to be more properly referable to the upper Miocene. No other upper Miocene is known.
Fig. 131.—The †gazelle-camel (†Stenomylus hitchcocki) of the lower Miocene. Restored from skeletons in the Carnegie Museum, Pittsburgh.