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Showing results for tags 'opalinoides'.
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From the album: Middle Jurassic Ammonites from Southern Germany
11cm. Murchisonae Zone, Upper Aalenian, Middle Jurassic. Wutach Valley. This one has almost completely lost its shell revealing the calcified mold showing the suture lines of the phragmacon. These were assigned to the genus Staufenia by Rieber in 1963, but Dietze, Rieber etal have revised the genera in December 2014 to the above.-
- aalenian
- ancolioceras
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This species has long been a subject of contention as to its lineage, but Dietze (2014), following the chronospecies/genus concept, has managed to prove to the satisfaction of most that it belongs to the subfamily of the Leioceratinae. Rieber (1963) had placed it in the subfamily Staufeniinae and had named it Staufenia opalinoides, a name which most collectors and paleontologists adopted, since his work was the most comprehensive one on the ammonite fauna of the area for many years. This almost complete specimen has most of its shell intact. The band of variation of ribbing and other sculptural factors is relatively broad, but this here is a typical sample. Biostratigraphy: Murchisonae Zone, Sinon Bank 1, haugi Subzone Old German Chronostratigraphy: Dogger (Braunjura) beta Literature: Rieber,H. (1963): Ammoniten und Stratigraphie des Braunjura beta der Schwaebischen Alb, Palaeontographica Bd.122,Abt.A, Pp.1-89 Dietze et al (2014): Aalenian (Middle Jurassic) ammonites and stratigraphy of the Geisingen clay pit (SW Germany), Palaeodiversity 7: 61–127 Horn,E. (1909): Die Harpoceraten der Murchisonae-Schichten des Donau-Rhein-Zuges, Mitteilungen der Großh. Badischen Geologischen Landesanstalt, VI. Bd.1.Heft