CT reconstruction of the partial holotype AMNH FF 20509 documents elongate fused branchial rays forming a corrugated operculate structure over posterior gill arches, adding a bounded Carboniferous body-plan sample to the early chondrichthyan record.
Represented range326–326 Ma
RegionsFayetteville Shale near Cove Creek, Searcy County, Arkansas, United States
The partial holotype AMNH FF 20509 of Cosmoselachus mehlingi from the Late Mississippian Fayetteville Shale preserves elongate rays from the hyoid and branchial arches fused into a corrugated operculum covering at least two posterior branchial arches.