Article: A new diapsid reptile from the uppermost Carboniferous (Stephanian) of Kansas

Diapsids represent one of the most diverse lineages within Amniota, yet, until recently, their Carboniferous record was restricted to one taxon from a single locality near Garnett, Kansas. Accordingly diapsids were thought not to have undergone the degree of evolutionary radiation which has been attributed to other Carboniferous amniotes. The description of Spinoaequalis schultzei gen. et sp. nov. from Upper Carboniferous deposits at Hamilton Quarry, Kansas, indicates that it is closely related to araeoscelidians and provides the first evidence for the diversification of diapsids within the Carboniferous. In addition Spinoaequalis possesses a suite of autapomorphies, most notably to the tail, which display evidence for thi earliest known aquatic specialization among amniotes.