Using community-level analyses, multiple isotope systems (e.g., oxygen or δ18Op, nitrogen or δ15NEB, zinc or δ66Zn), and tooth morphology, I investigate the trophic positions and structures, thermoregulatory strategies, environmental conditions, and habitat use of marine vertebrates and how these factors influence extinction dynamics across extinction events. This deep-time perspective provides critical insight into the drivers of biodiversity loss and recovery, helping us to anticipate how today’s marine communities may respond to accelerating global change.

Most extinct and extant sharks are ectothermic, with body temperatures that are similar to surrounding sea temperatures. Only a few modern shark taxa (e.g., great white and mako sharks) are known to produce and retain body heat in certain regions of their body (i.e., regional endothermy or mesothermy). Identifying mesothermy in extinct shark taxa and other marine vertebrates is hindered by the availability of preserved fossil materials. I am interested in the use of stable isotopes (e.g., δ18Op) from tooth enamel(oid) as proxies for identifying the presence and magnitude of mesothermy in extinct marine vertebrates in the Gulf Coastal Plain and Western Interior Seaway of North America. Increased body temperatures can influence a taxon's ecological success through time, particularly over extinction intervals or periods of climate fluctuation. I am interested in how thermoregulatory abilities contributed to the evolution or extinction of marine vertebrates across mass extinctions such as the end-Cretaceous.

Nitrogen isotopes of mineral-bound organic matter in tooth enamel(oid) (δ15NEB) provide a powerful tool for reconstructing the diets and trophic positions of extinct marine organisms and offer insights into the structure of ancient marine food webs. Integrating δ15NEB with other complementary isotope proxies (e.g., δ18Op) and traditional paleontological approaches (e.g., tooth morphology) enables the assessment of patterns of resource partitioning, niche differentiation, and ecosystem organization in deep time. My research uses δ15NEB to investigate the dietary ecology of Late Cretaceous shark communities and understand how ecological interactions changed over time, particularly mass extinction events such as the end-Cretaceous. This work seeks to advance our understanding of how shark communities responded to environmental change and evolutionary transitions over time.

During the Eocene (56-33.9 Ma), Earth's climate transitioned from warm greenhouse to cool icehouse conditions. δ18Op values in enameloid and analyses of tooth morphology are providing important information about shark ecology, paleoenvironmental conditions of marginal marine environments, and how a changing climate impacted shark ecology over time. This project focuses on fossil localities within the Gulf Coastal Plain of the USA, which was home to a variety of shark species across all life stages.