Phylogenomics and species delimitation of Crowned Snakes (Tantilla)
At the Florida Museum of Natural History, along with collaborators at the Smithsonian, we are working to resolve the taxonomy of the southeastern crowned snakes (Tantilla)—a group of fossorial, centipede-eating snakes native to the southeastern United States.
Our preliminary analyses show that traditional, morphology-based classifications are deeply discordant with patterns of genetic structure. In fact, both subspecies- and species-level classifications seem problematic in light of molecular data. To resolve the relationships among the snakes in this group, we are using genome-wide sequencing data to test species boundaries and establish a stable, well-supported taxonomy.
We also place these genetic patterns in a historical context. Past sea-level change has repeatedly fragmented the habitats across the southeastern United States, isolating populations of Tantilla for hundreds of thousands to millions of years. Untangling the resulting history—which likely involves introgression and ongoing gene flow—will help explain how the diversity in Tantilla evolved in the region.
Nuchal patterning was one of the primary characters used to diagnose different taxa within this group. We now know that much of the variation in this character does not reflect evolutionary relationships among these snakes, but it is still interesting to visualize. At right are photos of snakes I collected across the range of T. relicta to illustrate the variation once used to diagnose these snakes on a preliminary mitochondrial phylogeny. There are some surprises here that aren’t evident without tip labels, which we hope to unravel using the aforementioned genome-scale data.
This project has involved countless hours of fieldwork to address sampling gaps across Florida and adjacent states. Collecting Tantilla can be difficult, and when there’s little cover to flip, we often resort to digging in the sand. It’s a tedious but rewarding process. Searching for Tantilla also gives us the opportunity to collect other secretive psammophilic species, like mole skinks (Plestiodon egregius).
In collaboration with Nanjing Forestry University and Hainan Normal University, I have worked on multiple projects expanding our understanding of China’s herpetofauna. My role in these projects has primarily been focused on field-based research, including intensive surveys to document range extensions and new provincial records. Despite the basic nature of this, fieldwork in 2025 already yielded several notable findings, including numerous range extensions for snakes and salamanders, putative new species of Megophryid frogs, and collections of rare snakes that are already being incorporated into upcoming publications.
Chinese herpetology
Tracking down a short-tailed mamushi (Gloydius brevicauda) that escaped into thick vegetation
Collecting Hynobiid salamanders from a new locality in Yichang, Hubei.
See more photos here:
Snake fungal disease in endangered Kirtland’s Snakes (Clonophis kirtlandii)
During my time in Indiana, I collaborated with Indiana state officials and Dr. Drew Davis to sample Kirtland’s Snakes (Clonophis kirtlandii) for the fungus that causes snake fungal disease (Ophidiomyces ophidiicola). During the course of this project, we also collected genetic samples from all individuals and discovered new distribution records for C. kirtlandii, a species that is endangered throughout its distribution.
