RATES OF EVOLUTION IN THE DENTITION OF EARLY EOCENE CANTIUS - COMPARISON OF SIZE AND SHAPE

Cantius is an early Eocene adapid primate with an exceptionally well k nown fossil record. Measurements were recorded to describe the size an d shape of upper and lower first molars collected from a measured stra tigraphic section in the Clarks Fork Basin of Wyoming. Rates of change of size and shape are quantified by calculating evolutionary rates in standard deviation units per generation (haldanes). Temporal scaling of rates shows that change in size was generated by a significantly no nrandom directional process, while change in shape was generated by a significantly nonrandom stabilizing process. Size change in Cantius is interpreted to be the result of weak directional selection, and shape change is interpreted to be the result of strong stabilizing selectio n.