Fig. 283.—Right pes of †Patriofelis ferox. Cal., calcaneum. As., astragalus. Cb., cuboid. N., navicular. Cn. 1, 2, 3, internal, middle and external cuneiforms. (After Wortman.)
The limbs, especially the anterior pair, were short and very stout; the humerus had an immensely developed deltoid ridge, which extended down for two-thirds the length of the shaft, and a very prominent supinator ridge; the fore-arm bones, particularly the ulna, were heavy and the radius had but a limited power of rotation. The feet were short and broad, with five complete, spreading toes, ending in thick and blunt-pointed claws.
†Patriofelis was by far the most formidable of the Bridger Carnivora and, with the exception of †Harpagolestes, the largest. Its appearance must have been very curious, judged from the modern standpoint, with its disproportionately large, broad and rounded, leonine head, thick body and long, extremely heavy tail. The short, powerful limbs and broad feet must have given it something of the appearance of an otter. As in the case of so many other †creodonts, the combination of characters in the skeleton makes the question of habits a very puzzling one. The teeth had a form suited only to seizing and devouring prey, but the short legs and feet were not at all adapted to the swift movements, whether by long-continued running, or by stealthy approach and sudden leap, which are required in capturing agile prey, while the blunt claws could have rendered no service in holding a struggling creature. The form of the humerus and fore foot suggests burrowing habits, but it seems most unlikely that so large an animal could have lived in any such fashion. Terrestrial, arboreal and aquatic modes of life have all been suggested, and, all things considered, perhaps the least improbable conclusion is that †Patriofelis was more or less aquatic and preyed chiefly upon the fishes and turtles with which the Bridger waters abounded. This hypothesis of Dr. Wortman’s is supported by the otter-like form of the animal. Whatever the principal kind of food was, it must have been something that greatly abraded the teeth, which in old animals were mere stumps.
Fig. 284.—†Oxyæna lupina, Wasatch stage. Restored from a skeleton in the American Museum.
The Wind River representatives of the series are known only from fragments, which, so far as they go, are not separable from †Patriofelis. On the other hand, the Wasatch genus, †Oxyæna, is fairly well understood. This genus was very like its Bridger successor, but differed from it in just such ways as would be expected in an immediately ancestral form, that is to say, in smaller size and less advanced specialization. The number of teeth was not so far diminished: i 3/3, c 1/1, p 4/4, m 2/2, × 2 = 40; the carnassial teeth were the same, but they were less effective; the fourth upper premolar and first upper molar had large inner cusps, and in the latter the postero-external trenchant ridge was shorter. The second upper molar, lacking in †Patriofelis, was a transversely placed ridge, which engaged the heel of the second lower molar. The latter tooth, though larger than the first molar, was much less completely trenchant than in †Patriofelis and retained a small internal cusp and quite large heel. The skull resembled that of the Bridger genus, but the face was not so much shortened, the zygomatic arches were not so widely expanded or so massive, the lower jaw was not so heavy, nor the chin so steep. The body was relatively longer and more slender, the ribs being thinner and the chest shallower; the tail was even longer, but not nearly so thick. The articulations of the lumbar vertebræ were less complex. Except for their greater length and slenderness the limbs and feet were nearly identical with those of †Patriofelis.
In appearance, †Oxyæna must have been merely a smaller, lighter and less powerful variant of the Bridger genus, and, no doubt, its habits of life were substantially the same; but in the details of structure were many minor differences, all of them in the direction of greater primitiveness in the more ancient animal.