Dental function and diet in the Carpolestidae (Primates, Plesiadapiformes).

Abstract

Microwear analysis has long been used to infer dental function in primates; however, this is the first study to combine microwear and morphometric analyses to infer the dental function of the highly derived dentition of an early Tertiary primate. The Carpolestidae, a family of plesiadapiform primates, are characterized in part by a bladelike lower dentition (P4 and trigonid of M1). This study reveals a dual function of this dental complex. During the preparatory cycle, the tall, vertical enamel surfaces and broad basal lobes on P4 and trigonid of M1 probably functioned to wedge foods apart. This cycle is designated slicing-crushing and is uncommon among mammals, having been documented only for two extinct taxa: the multituberculates and the carpolestids. In addition to this special function, P4 and trigonid of M1 were used extensively with the molars in Phase I shearing. Facet analysis has revealed two new Phase I facets located on P3,4, whose formation is a result of normal Phase I movements and the derived morphology of these teeth. Slicing-crushing, used with Phase I shearing, would probably be most useful in processing food items of combined textures, particularly a soft interior covered by either a brittle or ductile coat, which are characteristic of an omnivorous diet composed of invertebrates, nuts, and seeds.