Determining the catalyst for the origin of euprimates ("true" primates) is critical to understanding the course of primate evolution. The foundation of the leading hypotheses of euprimate origins rests on the assertion that novel traits involved in food acquisition were the primary drivers of the initial euprimate diversification; however, the role that dietary niches played in establishing euprimates as successful members of early mammalian communities has not been explicitly addressed. This can only be tested by assessing the degree to which the dietary niche of euprimates overlapped with ecologically similar mammalian contemporaries (together, the"euprimate competitive guild"). Specifically, in order for dietary adaptations to have been at the root of euprimate origins, euprimates must have evolved either through the exploitation of an open dietary niche (absence of competition) or through the exclusion of non-euprimate competitors (strong competition). Weak competition is not consistent with this scenario. The purpose of this study is to determine the model of competitive interaction (absent, strong, or weak) that characterized the origination and early diversification of early Eocene North American euprimates. Competition is defined by niche overlap, and each competitive model is identified by a unique temporal pattern of dietary niche overlap among species. Dietary niches of each fossil species will be reconstructed using molar morphological measures found to discriminate dietary regimes within extant euprimate competitive guild samples. The degree of dietary niche separation between early euprimates and other members of the Eocene euprimate competitive guild will be evaluated statistically across a series of fossil samples from individual time intervals (Clarforkian 2-Wasatchian 5) at a single site, the Bighorn Basin. These observed patterns of dietary niche overlap over time, in conjunction with species abundance, predator origination profiles, and climatic variables, will be compared to the patterns expected under each competition model. This will, for the first time, enable a direct test of the validity of the standing hypotheses of euprimate origination.
|Effective start/end date||4/1/12 → 3/31/14|
- National Science Foundation (NSF): $16,425.00