Prospects for an upper Givetian substage

New ammonoid and conodont data from Germany, the Montagne Noire (France) and southeastern Morocco document a complex sequence of sedimentary events and faunal changes within an extended Givetian (late Middle Devonian) Taghanic Event Interval or Taghanic Biocrisis. Direct association of supposed typical middle Givetian ammonoids, trilobites and corals with upper Givetian marker taxa such as pharciceratids have been found, for example, in Moroccan and French time equivalents of the New York Upper Tully Limestone. The initial and eustatic Taghanic Onlap level is not known to be characterized by the first appearance of any widespread index conodont, goniatite or other taxon. A future upper Givetian substage, therefore, might be based either on the entry of Ozarkodina semialternans or on the first appearance of Schmidtognathus hermanni. The semialternans Zone correlates with a third sedimentary cycle within the Tully Limestone and with the spread of the first Pharciceratidae. Eobeloceratidae ( Mzerrebites juvenocostatus ) and Archoceratidae n. fam. ( Atlantoceras ). The (Lower) hermanni Zone is marked by a post‐event transgression which led to a significant conodont radiation and to a further diversification of Pharciceratidae and Eobeloceratidae ( Mz. erraticus ).