WHATCHEERID MATERIAL FROM NORTH-CENTRAL KENTUCKY AND THE VERTEBRATE FAUNA OF THE MISSISSIPPIAN OF NORTH AMERICA

A vertebrate assemblage from the Mississippian (Namurian: Elvirian) Buffalo Wallow Formation of north-central Kentucky (Hancock County) preserves articulated and disarticulated vertebrae, a cleithrum, and clavicles of a whatcheeriid tetrapod. The vertebrae and cleithrum possess apomorphies of Whatcheeria, such as the construction of the inter- and pleuroentra and the dorsal notch on the cleithrum, while other material is similar to both known whatcheerids and embolomeres. Differences between previously described examples of Whatcheeria and the material from Hancock include the greater expansion of the dorsal portion of the cleithrum and the articulation of the ribs heads with both the inter- and pleurocentra. Whatcheeria is known from Greer, West Virginia in the Appalachian Basin, and Delta, Iowa and Hancock County, Kentucky in the Illinois Basin, a distribution similar to the tetrapod Greererpeton and the lungfish Tranodis, suggesting a degree of provinciality in North America during the Mississippian. This collection of taxa appear to define a distinct Mississippian vertebrate province, here termed the Illinois Basin Vertebrate Province, separate from British Carboniferous localities. However, the presence of Agelodus at Hancock County suggests a possible association with Gondwana as this taxon is known from both North America and Australia. Faunal similarities between Australia and North America during the Carboniferous have previously been demonstrated in the distribution of the rhizodontiform Strepsodus.