Abstract Chrono-, litho- and biostratigraphy across the Devonian–Carboniferous transition are reviewed to provide a precise time framework for the global Hangenberg Crisis and for the current search for a revised basal Carboniferous Global Stratotype Section and Point (GSSP). The outer shelf deposits of the Rhenish Massif (Germany) form a lithological standard. Pre- (main Wocklum Limestone), lower (top Wocklum Limestone/Drewer Sandstone to Hangenberg Black Shale), middle (Hangenberg Shale/Sandstone), upper (Stockum Limestone), and post-crisis (Hangenberg Limestone) deposits are defined. Combined with the conodont, ammonoid and miospore zonations and eustatic trends, this succession can be correlated internationally. The contemporaneous successions of the Ardennes serve as a reference for shallow shelf settings. The positive and negative aspects of five options for a redefined Devonian–Carboniferous boundary level are discussed: (1) base of the black shale (main extinction level, base of Bispathodus costatus–Protognathodus kockeli Interregnum and LN Zone), (2) sequence boundary (widespread unconformities) or glacial and regressive peak (base of Hangenberg Sandstone), (3) base of the kockeli Zone and of initial postglacial transgression (base of lower Stockum Limestone), (4) entry of Siphonodella ( Eosiphonodella ) sulcata (base of upper Stockum Limestone), and (5) base of post-crisis interval (base of Hangenberg Limestone), at approximately the poorly correlated current GSSP level. Due to homonymy, Siphonodella ( Siphonodella ) hassi Ji, 1985 is renamed as Siphonodella ( Siphonodella ) jii nom. nov. Consequently, the mid-lower Tournaisian S. ( S .) hassi Zone (previous Upper S. ( S. ) duplicata Zone) becomes the S. ( S. ) jii Zone.

Abstract Carboniferous conodont biostratigraphy comprises regional zonations that reflect the palaeogeographical distribution of taxa and distinct shallow-water and deep-water conodont biofacies. Some species have a global distribution and can effect high quality correlations. These taxa are incorporated into definitions of global Carboniferous chronostratigraphic units. A standard global Carboniferous zonation has not been developed. The lowermost Mississippian is zoned by Siphonodella species, excepet in shallow-water facies, where other polygnathids are used. Gnathodus species radiated during the Tournaisian and are used to define many Mississippian zones. A late Tournaisian maximum in diversity, characterized by short-lived genera, was followed by lower diversity faunas of Gnathodus species and carminate genera through the Visean and Serpukhovian. By the late Visean and Serpukhovian, Lochriea provides better biostratigraphic resolution. Shallow-water zonations based on Cavusgnathus and Mestognathus are difficult to correlate. An extinction event near the base of the Pennsylvanian was followed by the appearance of new gnathodid genera: Rhachistognathus , Declinognathodus , Neognathodus , Idiognathoides and Idiognathodus . By the middle of the Moscovian, few genera remained: Idiognathodus , Neognathodus and Swadelina. During the middle Kasimovian and Gzhelian, only Idiognathodus and Streptognathodus species were common. Near the end of the Gzhelian, a rediversification of Streptognathodus species extended into the Cisuralian.