| Species | Pseudaetomoceras abnormilobatus (WÄHNER) |
| Author | WÄHNER |
| Group | Arieten |
| Horizon | atanatense-horizon |
| Zone | marmoreum-zone |
| Stage | Upper Hettangian |
Description
The species is narrow-billed and has a highly oval WQ, flattened flanks and an extremely sharpened external side. A razor-sharp keel is developed.
The strong ribs start slightly retroradiate at the umbilical edge, run straight and slightly retroradiate over the flanks to then bend strongly forward near the external side and end in the keel. Many specimens of P. abnormilobatus found are very small.
P. abnormilobatus occurs mainly (or only?) in the ammonite horizon with D. atanatense, whereas P. castagnolai is already present below, together with A. marmoreum.
* Description according to Wähner (1886), supplemented
Compare
Characteristic for this species are the strong sharpening of the external side and the small navel width. A development from Alsatites doetzkirchneri via Pseudaetomoceras castagnolai to P. abnormilobatus can be seen, whereby the sharpening of the external side and the winding height constantly increase and the navel width decreases.
P. castagnolai is also distinguished by a uniform bending of the ribs.
Dimension
Dimensions at D= 57mm (according to Kment):
Nw % v. D: ca. 38%
Wh % v. D: ca. 35%
Wb % v. D: ca. 15%
Literature
- 1886 Arietites abnormilobatus n.f. – Wähner S. 148, Taf, 38.4-7
- 2000 Pseudaetomoceras abnormilobatus Wähner – Kment S. 205
