Lemur Diversification

Model for lemur evolution from Fulwood et al. (2021)

My dissertation focused on dietary adaptation and diversification in lemurs. I worked with a team of biologists and mathematicians to apply new tools for understanding the functional shape of teeth and reconstructing ancestral tooth shape. We were able to clarify how tooth shape relates to dietary ecology and local precipitation in lemurs, reconstruct the diets of extinct subfossil lemurs, and propose a new model for the diversification of lemurs that emphasizes the exploitation of defended plant resources as forests may have spread during the Oligocene (Fulwood et al. 2020, 2021a, 2021b).

Eocene Primate Diversity

Zachos et al. (2001) global temperature curve

Primates flourished in North America across the relatively warm and wet Early and Middle Eocene, which is consistent with their modern distribution in largely tropical rain forest habitats. This suggests that global temperatures may represent a proxy for primate ecospace availability on northern continents. With colleagues, I am working to examine the relationship between this ecospace availability and morphological diversity in Eocene euprimates, with a particular focus on dietary adaptation and body mass (Fulwood et al., SVP 2021).

Dental morphology on the adaptive landscape

Phylomorphospace of strepsirrhine primate protoconid shapes defined using the slope and intercept of radius by length from tip (ongoing work)

I am broadly interested in exploring new ways to quantify tooth shape and create functional morphospaces that can be used to address fundamental predictions of macroevolutionary theory. I am currently working with colleagues to explore methods for describing tooth morphology using the simple power law variables recently described by Evans et al. (2020) in combination with functional dental topography metrics and adaptive landscape modelling methods as first outlined by Polly (2016). I’m also interested in applying dental topography metrics, power law approaches, and mathematical characterization of the adaptive landscape to revisit classic studies of morphological change across stratigraphically high-resolution sequences evolving lineages in the primate fossil record (Rose and Bown 1984; Clyde and Gingerich 1994).

The Eocene-Oligocene transition

Rudolph F. Zallinger’s “The Age of Mammals,” detail on the Oligocene

From the end of the Middle Eocene to the end of the Oligocene, North America endured several significant environmental and faunal changes. The groups of mammals characteristic of Eocene faunas, including primates, went extinct, and were replaced by radiating members of new groups, including oreodont herbivores and nimravid carnivores, which themselves decline toward the end of the Oligocene. I am interested in better understanding the effects of environmental changes, extinctions, and immigrations on the functional diversity of North American mammals across this interval, with a particular focus on the implications of primate extinctions on North American faunas.

Freshwater mussel morphology

Cyclonaias pustulosa, the Pimpleback

A diverse assemblage of freshwater mussels occurs in watersheds throughout North America, and Tennessee is a mussel biodiversity epicenter. I am interested in quantifying mussel morphological diversity along rivers and relating shape to the hydrological conditions experienced at different stream positions. I have begun a major digitization project with the McClung Museum at the University of Tennessee focused on collections of two species of Cyclonaias (C. pustulosa and C. tuberculata) from the Clinch River in Tennessee and Virginia. I hope to use morphometric tools to quantify valve shape and decoration and compare inter- and intra-specific variation against functional predictions.