A MARINE VERTEBRATE FAUNA FROM THE ASSELIAN STAGE (EARLY PERMIAN) OF EASTERN KANSAS, USA

The sedimentary rocks from the earliest Permian of Kansas are one of the richest regions for early Permian marine vertebrates, especially chondrichthyans, in the world. Here we report a species-rich fauna from a roadside exposure of the Neva Limestone (Permian, Cisuralian, Asselian). In the unit studied, we recovered remains of large ctenacanthids and petalodontids. Orodontiform chondrichtyans were also present along with neoselachians, symmorriforms, hybodontiforms, and paleonisciform fishes. Hybodontiform chondrichthyans are represented by several taxa. While some hybodontiform teeth appear similar to teeth from younger Cisuralian taxa (such as ?Polyacrodus from the Artinskian Stage), others appear more similar to upper Carboniferous taxa (such as Dabasacanthus from the Gzhelian Stage). This suggests that the early Permian seaways of what is now Kansas preserve a clear record of the biogeographic transition from Carboniferous marine vertebrate communities into more typically Permian communities.