Strigilodus tollesonae

Strigilodus tollesonae was identified within the Ste. Genevieve Formation rock layer at Mammoth Cave National Park in Kentucky during an ongoing paleontological resources inventory (PRI) led by the National Park Service Paleontology Program in 2023. The discovery of the species was made when several spoon-like teeth were found embedded in a cave wall and ceiling during the PRI, which commenced in November 2019. The finding was officially announced on National Fossil Day in October 2023.[1] The species was one of at least 70 species of ancient fish identified in the 350-million-year-old cave.[2]

The epithet tollesonae is in honor of Mammoth Cave National Park guide Kelli Tolleson, who played a pivotal role in supporting the paleontological research by providing field assistance during the PRI.[1]

Strigilodus tollesonae exhibits distinctive dental traits, characterized by spoonlike cusps with a rounded shape, representing all tooth positions. The arrangement, featuring V- to U-shaped lingual cristae,[3] distinguishes it from other contemporary sharks and rays. The central tooth, larger in size, is flanked by three smaller teeth of diminishing size. Each tooth possesses a singular rounded curved cusp, designed for efficiently clipping and grasping hard-shell prey. The elongated inner/tongue side of the tooth, with ridges facilitating crushing, further emphasizes the unique dental morphology. This specialized dental structure, observed in both adult and juvenile specimens, suggests an adapted feeding strategy, potentially akin to that of a modern skate, with a diet encompassing snails, bivalves, soft-bodied worms, and smaller fish.[4]