Department of the Interior: US Geological Survey Monograph 55: The Titanotheres of Ancient Wyoming, Dakota and Nebraska

Abstract

THE Titanotheres are a group of odd-toed hoofed mammals which lived during the early part of the Tertiary epoch about the fortieth parallel of latitude in North America and Asia, and occasionally strayed into eastern Europe. They are peculiar in their low-crowned molar teeth, which never became sufficiently deepened to be useful for feeding on dry vegetation. They are also unique among odd-toed hoofed mammals in having the forefoot almost like that of the even-toed hippopotamus, with only a slight tendency towards the greatest weight on the third toe. So far as known, they first appeared at the end of the Lower Eocene period, when they were small hornless dwellers in swamps, evidently feeding on succulent vegetation. They became extinct at the end of the Lower Oligocene period, when most of them had grown to be as large as rhinoceroses or even as small elephants, adapted to live on hard ground, with prehensile lips for browsing, and with a pair of horns, supported by bony cores, on the top of the prominent nose. The fossil remains of these large forms were found first, and hence the name given to the group.

Department of the Interior: U.S. Geological Survey. Monograph 55: The Titanotheres of Ancient Wyoming, Dakota and Nebraska.

By Henry Fairfield Osborn. Vol. 1. Pp. xxiv + 701 + plates 1–42. Vol. 2. Pp. xi + 703–953 + plates 43–236. (Washington, D.C.: Government Printing Office, 1929.) 9 dollars.