| Species | Megastomoceras pachydiscus (WÄHNER) |
| Author | WÄHNER |
| Group | Psiloceraten |
| Horizon | curviornatum-horizon |
| Zone | megastoma-Zone |
| Stage | Middle Hettangian |
Description
The cross-section of the windings is oval, the umbilical drop is relatively broadly rounded, the outer side as well. The coils reach their greatest thickness approximately in the middle of the curved flank. The inner coils are quite strongly ribbed. The course of the ribs cannot be reproduced because Wähner, like us, only had one large specimen. Where they can be fully observed, they bend forward near the outer side.
The ribbing becomes progressively weaker and more irregular, on the external side the extensions of the ribs can still be traced most clearly. On the living chamber and on the flank near the mouth, numerous accretion stripes are visible.
* Description according to Wähner (1883), supplemented
Compare
The shape of the shell of M. pachydiscus is reminiscent of Laqueoceras crebricinctum. The thickness of the shell and the course of the ribs, on the other hand, are reminiscent of Megastomoceras.
Like Wähner, we also have only one complete, large copy, which corresponds very well with this one.
What youth copies look like cannot be decided.
Dimension
Dimensions with D= 130mm
Nw % v. D: ca. 49%
Wh % v. D: ca. 29%
Wb % v. D: ca. 24%
Literature
- 1884 Aegoceras pachydiscus n.f. – Wähner, S. 152, Taf. 17,1
