An evaluation of French amniote diversity through the Pennsylvanian-Cisuralian boundary

Amniotes are rare in Late Carboniferous strata, especially in Europe, and despite a global diversification. They are generally more common in Lower Permian deposits. The French record around the Pennsylvanian-Cisuralian boundary is therefore re-examined. Each basin which yielded amniote remains is provided with general data on its sedimentology, stratigraphy, dating, and palaeontological content. Seven specimens are reported, of which five are synapsids and two are reptiles, each of them being a holotype. Their respective age is reassessed. The use of the regional Stephanian and Autunian stages is discussed, but their traditional sense is retained. There is currently no amniote in the Stephanian sensu stricto (= Early Gzhelian) of France. The Stephanian-Autunian Transitional Zone (= Late Gzhelian) contains the unique amniote Stereorachis blanziacensis. The Autunian sensu stricto (= Asselian) contains five, Stereorachis dominans, Haptodus baylei, Callibrachion gaudryi, Belebey augustodunensis, and Aphelosaurus lutevensis. Finally, Neosaurus cynodus can be assigned either to the Transitional Zone or to the Autunian sensu stricto. The amniote diversity increases through the Pennsylvanian-Cisuralian boundary. Despite the low number of specimens, the French record is representative of the global evolution of amniotes.