The pharciceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Abstract

The ammonoids of the suborder Pharciceratina from the Red Ironstone Formation of the area around Dillenburg (eastern Rhenish Mountains) are revised, mainly based on historical collections stored in the Museum für Naturkunde, Berlin. The genus Evopharciceras gen. nov. and the following species are newly described: Maenioceras ornatum sp. nov., Pharciceras beyrichi sp. nov., Pharciceras kruegeri sp. nov., Pharciceras ferrum sp. nov., Evopharciceras formosum gen. et sp. nov., Extropharciceras metallicum sp. nov., Lunupharciceras kochi sp. nov., Stenopharciceras lotzi sp. nov., Pluripharciceras ahlburgi sp. nov. and Sandbergeroceras archiaci sp. nov. Neotypes are proposed for the species Extropharciceras becheri (von Buch, 1832) and Sandbergeroceras costatum (d’Archiac & de Verneuil, 1842). The stratigraphic distribution of the genera is discussed; they are assigned to three assemblages: (1) Maenioceras terebratum Zone (early Givetian; two species), (2) Pseudoprobeloceras pernai Zone (latest Givetian; fifteen species) and (3) Sandbergeroceras costatum Zone (early Frasnian; three species).

The early gephuroceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

“…In the meantime, two monographs on the ammonoids of the Red Ironstone have been published; these dealt with the suborders Pharciceratina (Korn & Bockwinkel 2021) and Tornoceratina (Korn & Bockwinkel 2022). In a third step of the revision, we here present the re-description of the ammonoids of the suborder Gephuroceratina, of which eight species are described.…”

“…In two recently published monographs (Korn & Bockwinkel 2021, 2022, the material of the suborder Pharciceratina and Tornoceratina from Dillenburg was studied in detail. Here follows the third part with the description of the early representatives of the Gephuroceratina from the Roteisenstein Formation of the Dillenburg region.…”

“…(1) Pseudoprobeloceras pernai Zone (late Givetian), in which species of the genera Pseudoprobeloceras, Ponticeras, Darkaoceras and Taouzites co-occur with various pharciceratids (genera Pharciceras Hyatt, 1884, Evopharciceras Korn & Bockwinkel, 2021, Extropharciceras Bockwinkel, Becker & Ebbighausen, 2009, Stenopharciceras Montesinos & Henn, 1986, Synpharciceras Schindewolf, 1940, Pluripharciceras Bockwinkel, Becker & Ebbighausen, 2013). For instance, the gephuroceratids are known from localities (e.g., Prinzkessel Mine and "Tiefe Grube" near Oberscheld) and lithology, which yielded specimens of the genera Pharciceras, Lunupharciceras Korn in Korn & Klug, 2002 and Synpharciceras.…”

The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

“…The ammonoids of the suborder Tornoceratina form only a small part of the ammonoid assemblage from the Red Ironstone Formation in the area around Dillenburg (Eastern Rhenish Mountains). In terms of specimen abundance and species diversity, they are far behind the co-occurring suborders Pharciceratina (Korn & Bockwinkel, 2021) and Gephuroceratina. Their revision, mainly based on historical collections kept at the Museum für Naturkunde, Berlin, leads to the distinction of five species belonging to four genera:…”

“…In a recently published monograph (Korn & Bockwinkel 2021), the material of the suborder Pharciceratina from Dillenburg was studied in detail. Here, we present the description of the Tornoceratina from the Roteisenstein of the Dillenburg region.…”