ABSTRACT.- The Upper Famennian ammonoid fauna is characterized by the predominance of the clymeniids,
   which became extinct in the topmost Devonian.  The Hangenberg Black Shale marks the incision of ammonoid
   diversity.  Survivors are only Mimimitoceras, Wocklumeria, Lissoclymenia and Cymaclymenia, which in two sections
   (Müssenberg, Drewer) occur in beds above the Hangenberg Black Shale together with species of Acutimitoceras
   in the prorsum Zone.  The Gattendorfia Stufe fauna evolved rapidly after the extinction of the clymeniids.  The
   new taxa Globimitoceras gen. nov., Nicimitoceras gen. nov., and Mimimitoceras hoennense sp. nov. are proposed.