Morphology and variation in the posterior dentition of Picrodus silberlingi (Picrodontidae).

The Picrodontidae is a unique family of early Tertiary Primates. Previous discussions of picrodontid dental morphology centered on limited samples. This analysis uses a much larger sample to more completely describe the posterior dentition of Picrodus silberlingi. A diagnostic feature of the members of this family is the presence of a highly modified and enlarged anterior cheek tooth. This tooth, generally regarded as a first molar, displays the highest degree of discrete variation. The remaining molars, although unusual for plesiadapiforms, are less variable in both metric and nonmetric characteristics. The morphology of these cheek teeth is analogous to that of the nectar and pollen eating Glossophagine bats and suggests that the picrodontids possessed a similar dietary adaptation. The results of this analysis support the retention of P. silberlingi as a single species, even though a temporal increase in size was noted. P. silberlingi appears significantly larger than the newly described species Picrodus (= Draconodus) apertus.