My research builds better bridges between the fossil record and other branches of evolutionary biology, making the field of paleontology better equipped to deliver on its promise as a testing ground for biological theory applied at enormous scale. The strength of paleontology is its empirical record. However, this strength can only be realized when the empirical record is interpretable. Interpretability is the bridge allowing me to cross timescales and connect results in the fossil record to species on the landscape today. 

Strong empirical bridges require accounting for pragmatic data collection. In my case, the more information that can be inferred from common fossils, the wider and more usable a timescale-crossing bridge will be. The challenge is that the most common vertebrate fossils—isolated teeth and fragmentary bones—are also usually the most information-poor. My work improves the amount of recoverable information retained in these abundant, but incomplete sources of evidence. Mainly, I do so by studying modern, more information-rich species to see what information preservable in fossils forms a reliable signal of ecology and evolution. For me, this information is morphometric, measurable in some aspect of the size, shape, and texture of bones and, in particular, teeth. 

An early publication from this line of research looked at phenotypic and genetic discordance in grasshopper mice (Onychomys leucogaster) as a way of asking what tooth  morphology can tell us about shallow genetic diversification. Student projects also emerge as the lab explores ecological and  evolutionary signals in these complex phenotypes. Other in-progress research is exploring additional species, phenotypic plasticity, and novel phenotyping methods that improve the range and precision of what we can infer from isolated teeth in the fossil record (example). 

In the fossil record, I primarily work to understand how unbranching lineages (species or linked anagenetic species) change over time and in relation to their environment. Such studies are only possible in richly studied, exceptional fossil records such as that of the Bighorn Basin, Wyoming. There, my research is focused on changes in the dentition of lineages of small mammals through the climate change of the Paleocene-Eocene Thermal Maximum (PETM) ~56 million years ago (more on the PETM here).

In summer field seasons we collect fossils of these small mammals through intensive screenwashing efforts. Back in the lab, I digitize these fossils via microCT, then use a series of morphometric analyses to quantify differences in morphology across species and over time (Vitek et al., 2017). 

A side effect of these morphometric analyses is a rigorous identification process that accounts for intraspecific variation. This foundational taxonomic and systematic work contributes to an unparalleled collection of data regarding the changing  abundance and distribution of small mammals during the high-magnitude climate change of the Paleocene-Eocene Thermal Maximum.

Recently soft-shelled turtle shells have become a complement to mammalian teeth. Both morphological systems are opportune systems for testing how re-envisioning morphological traits from a developmental basis might change (and even improve?) our inferences of evolutionary history at both microevolutionary and macroevolutionary scales. Like isolated mammalian teeth, turtle shells are common in the fossil record and offer the opportunity of a dense fossil record -- if their morphology can be interpreted in a biologically meaningful way. 

This work includes explorations of how we might borrow tools from research on Turing-like patterns, animal coloration, and engineering texture metrology, among other subfields, to bear on questions of turtle shell texture patterns. Early results are promising. 

Prior Work: Soft-shelled turtles (Testudines: Cryptodira: Trionychidae) have a fossil record spanning six continents and 125 million years of geologic time. Despite that wealth of opportunity, accurately discerning species limits and sifting out broader patterns of evolution from intraspecific variation and homoplasy is a major challenge. With international colleagues in Russia, Japan, and Switzerland, I take the approach of incorporating evaluations of intraspecific variation into taxonomic evaluations and phylogenetic analyses of Asian and North American fossils of soft-shelled turtles from the Cretaceous through the Miocene. Results include a comprehensive review of the North American fossil record of trionychids (Vitek and Joyce, 2015)  and the links between patterns of gigantism, high diversity, and warm climates (Vitek, 2012). To get a sense of what gigantism means for soft-shelled turtles, imagine a turtle the size of the the one in this video living in Wyoming ~50 million years ago. 

Through the Turkana Basin Institute, I collaborate on various studies of vertebrate fossils from the Turkana Basin, Kenya. You might find me or members of the lab working to characterize mammalian diversity in a new Oligocene site, Topernawi, and compare it to what we know about diversity in other East African sites. You might find one of us contributing morphometric analyses or screenwashing help to other projects ongoing in the basin. Together, the goal of most of these projects is to better understand how vertebrate diversity in Africa came to be. 

The Eastern Box Turtle (Terrapene carolina), is a long-standing example of the difficulty of categorizing intraspecific variation across space and time. The classification of extant populations is still contentious after over 250 years of study. Significant amounts of geographic, allometric, and sexually dimorphic variation all contribute to complexity within the species. A relatively abundant Pleistocene record further complicates evolutionary interpretations rather than clarifying the history of the species.

My approach to understanding spatiotemporal evolution in Terrapene carolina is to quantify variation of carapace shape, a phenotypic system that can be equally applied to fossil and modern record. Using geometric morphometrics and metadata available in museum collections across the United States, I am placing temporal variation in the context of multiple sources of variation and previous interpretations of the fossil record.

As an undergraduate, I worked on a small project with Drs. Jakob Vinther, Jim Schiffbauer, Derek Briggs, and Rick Prum about the preservation and color patterns of a fossilized feather from the Messel Shale. We were able to put together a model to explain the red-and-white, striped coloration of an extremely well-preserved fossil by integrating taphonomy, microscopy, and physics.  Our work went into a paper, “Exceptional three-dimensional preservation and coloration of an originally iridescent fossil feather from the Middle Eocene Messel Oil Shale”.