Janassid petalodonts (Chondrichthyes, Petalodontiformes, Janassidae) from the middle Mississippian (Viséan) Ste. Genevieve Formation, Mammoth Cave National Park, Kentucky, USA

A new genus and species of janassid petalodont, Strigilodus tollesonae, has been identified from isolated teeth discovered within the Middle Mississippian (Viséan) Joppa Member of the Ste. Genevieve Formation at Mammoth Cave National Park, Kentucky. This marks the first record of this chondrichthyan group in the formation. The study analyzed dental structures, revealing rounded spoonlike cusps and V- to U-shaped lingual cristae unique to Strigilodus. Additionally, Janassa sp. was identified within the same formation. Dental reconstructions for Strigilodus and Cypripediodens cristatus suggest distinct feeding adaptations, with Strigilodus showing similarities to Janassa, while Cypripediodens exhibited a possible extreme form of durophage (hard-shelled prey) feeding. The research proposes two subfamilies within Janassidae: Janassinae, including Janassa and Strigilodus, and Cholodinae, comprising Cholodus, Cypripediodens, and Cavusodus.

Hodnett, J.-P. M., Toomey, R., Olson, R., Tweet, J. S., & Santucci, V. L. (2023). Janassid petalodonts (Chondrichthyes, Petalodontiformes, Janassidae) from the middle Mississippian (Viséan) Ste. Genevieve Formation, Mammoth Cave National Park, Kentucky, USA. Historical Biology, 36(9), 1783–1792. https://doi.org/10.1080/08912963.2023.2231955