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

ABSTRACT

Isolated teeth of two janassid petalodonts collected from cave passages within the Middle Mississippian (Viséan) Joppa Member of the Ste. Genevieve Formation at Mammoth Cave National Park, Kentucky represents the first record of this group of chondrichthyans from this formation. A new janassid, Strigilodus tollesonae, gen et sp. nov., is recognised from isolated teeth, representing all tooth families, and are characterised by their rounded spoonlike cusps and V- to U-shaped lingual cristae. Janassa sp. is also present within the Joppa Member of the Ste. Genevieve Formation. Dental reconstructions are proposed for Strigilodus tollesonae and Cypripediodens cristatus, modelled after previous observations for Janassa dentitions. Strigilodus had a dental arrangement more similar to Janassa, while Cypripediodens was uniquely adapted for a possible extreme form of durophage feeding. We propose that within Janassidae, there were two unnamed subfamilies with Janassa and Strigilodus forming the Janassinae, while Cholodus, Cypripediodens, and Cavusodus forming Cholodinae subfam. nov. urn:lsid:zoobank.org:act:763F8777-22A0-44CB-A520-CACCA49DF57Aurn:lsid:zoobank.org:act:01EB9ACE-B3EA-4EA3-8F00-A158BAE4E1ACurn:lsid:zoobank.org:act:B83202DB-644A-4518-BC6F-E161E16C4553

KEYWORDS:

• Ste. Genevieve Formation
• Mammoth Cave National Park
• Mississippian
• Carboniferous
• petalodont
• Janassidae
• Chondrichthyes
• Strigilodus
• Janassa

Acknowledgments

We are greatly indebted to Mammoth Cave National Park (MACA) Superintendent Barclay Trimble and head of the MACA Science and Resource Management unit, Timothy Pinion, for their support of our paleontological resource inventory and research into the Mississippian fish assemblages. The success of our project is largely in part due to a dedicated group of staff and volunteers who have helped us document new fossil localities and spot new fossils within the passages of Mammoth Cave. Park educator and guide Kelli Tolleson and guide Rich Boldon have been instrumental in the discovery of a number of new fossil localities for this project. We appreciate Terry Langford and Isabel Sonora for managing the Mammoth Cave National Park Museum’s fossil collections we have generated during this project. We also thank our fossil “spotters” Kailey Alessi, Bryce Belanger, Matt Cecil, Magnus Cleveland, Joe Douglas, Amber Flowers, Chris Groves, Mandolin Harris, Ed Jakaitis, Pat Kambesis, Nathan Leies, Mike May, Karoyn Mikowski, Marissa Schorr, Stacey South, Barclay Trimble and Elizabeth Winkler. JPH particularly thanks Eileen Grogan and Richard Lund for their conversations on petalodont morphology, ecology and evolution while a student in their lab that helped with our understanding of the group. We also thank Wayne Itano, David Elliott and Chase Egli for their discussion and comments on petalodonts. We thank Wayne Itano, Ryan Shell and Nicholas Gardner for reviewing this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).