Current Research

CT scanning reveals nutritive canals (blue) within the tooth (gray) of Carcharopsis wortheni, one of the earliest chondrichthyans with serrated teeth. Bronson et al. 2018

Anatomy of Paleozoic Chondrichthyans

Using CT scanning, we are investigating well-preserved chondrichthyan skeletons, especially those from the Late Mississippian Fayetteville Shale (in what is now Arkansas, Oklahoma, and Texas). This work is in collaboration with Dr. John Maisey (American Museum of Natural History), Dr. Alan Pradel (Muséum national d'histoire naturelle), and Dr. Royal Mapes (Ohio University).

Scanning electron micrograph of the olfactory rosette of a freshwater catfish.

Cranial and Sensory Anatomy of Living Fishes

Current research in the lab spans a wide range of taxonomic groups, including sensory anatomy of freshwater catfish and anadromous salmonids, developmental anatomy of sturgeon, and skeletal and endocast anatomy of living chondrichthyans.

3D rendering of the inner ear skeletal labyrinth of Sphyrna tiburo (bonnethead shark); anterior to left.

Inner Ear Variation in Living Chondrichthyans

The shape of the inner ear (specifically the skeletal labyrinth of the semicircular canals) has been correlated with habitat and locomotion in several tetrapod groups. We seek to understand whether a similar ecomorphological correlation exists in the ear of cartilaginous fishes.

3D rendering of the inner ear skeletal labyrinth of a 300 million year old stethacanthiform chondrichthyan from the Fayetteville Shale, showing a lack of specializations for LFSD. Anterior to left.

Evolution of Inner Ear Specializations in Early Cartilaginous Fishes

The inner ear of modern sharks contains numerous specializations for low frequency sound detection (LFSD). How early in shark evolution did these traits arise? Reconstructing early chondrichthyan fossils can help us elucidate the time and nature of this transition.