Wc. Clyde et Pd. Gingerich, RATES OF EVOLUTION IN THE DENTITION OF EARLY EOCENE CANTIUS - COMPARISON OF SIZE AND SHAPE, Paleobiology, 20(4), 1994, pp. 506-522
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.