| Species | Megastomoceras panzneri (WÄHNER) |
| Author | WÄHNER |
| Group | Psiloceraten |
| Horizon | curviornatum-horizon |
| Zone | megastoma-Zone |
| Stage | Middle Hettangian |
Description
Megastomoceras panzneri is very densely ribbed after the nodule stage typical of Storthoceras & Megastomoceras. The ribs are slightly s-shaped on the flanks, bend forward near the external side and then extinguish.
The cross-section of the windings is oval, but the outer side is always more or less sharpened like a roof. Although the ribs run almost to the centre of the outer side, this always remains smooth.
* Description according to Lange (1952), supplemented
Compare
Compared to Megastomoceras megastoma and Megastomoceras anisophyllum, which are very
Megastomoceras panzneri has a wider navel, less thickness and thinner, more numerous ribs.
Very similar is Megastomoceras paltar. This species, however, has a more highly oval cross-section of the coils, with the greatest thickness clearly measured near the umbilicus and the flanks inclining towards the external side. This inclination can also be observed in the very large specimen of M. panzneri in Wähner and is probably a symptom of age.
Small specimens resemble species of the Storthoceras extracostatum group. However, they all have a broadly rounded external side.
Dimension
Dimensions with D= 41mm
Nw % v. D: ca. 44%
Wh % v. D: ca. 34%
Wb % v. D: ca. 27%
Literature
- 1882 Aegoceras panzneri n.f. – Wähner S. 81, Taf, 15.1-2, Taf. 21.3
- 1952 Storthoceras (Megastomoceras) panzneri Wähner – Lange, S. 135, Taf. 16.12-14
