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| Macadens olsoni Hodnett, Toomey, Sues, Santucci, Tolleson & Tweet, 2025 Art by Benji Paysnoe |
A new euchondrocephalan chondrichthyan, Macadens olsoni gen. et sp. nov., is identified from the Middle Mississippian (Viséan) Joppa Member, Ste. Geneveive Formation from Mammoth Cave National Park, Kentucky. Macadens olsoni shares various morphological traits with the enigmatic taxon “Helodus” coxanus Newberry 1897, from the Lower-Middle Mississippian (Tournaisian) Keokuk Limestone of Iowa. These morphological traits of a lower symphyseal on a narrow mesiodistally elongated base with rounded and blunt cusps are not seen in Helodus and we create a new genus name and combination, Rotuladens gen. nov. coxanus Newberry 1897. Macadens and Rotuladens are proposed as members of unnamed clade with a sister-group relationship with Eugeneodontiformes.
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| Proposed reconstruction of the new to science species Macadens olsoni, discovered through fossil research at Mammoth Cave National Park. Art by Benji Paysnoe |
Macadens olsoni gen. et sp. nov.
John-Paul Michael Hodnett, Rickard Toomey, Hans-Dieter Sues, Vincent L. Santucci, Kelli Tolleson and Justin Tweet. 2025. A New euchondrocephalan chondrichthyan (Chondrichthyes, Euchondrocephali) from the middle Mississippian (Viséan) Joppa Member of the Ste. Genevieve Formation at Mammoth Cave National Park, Kentucky, USA and A Reassessment of the lower Mississippian (Tournaisian-Viséan) "Helodus" coxanus Newberry, 1897. New Mexico Museum of Natural History and Science Bulletin. 100: 87–93.
