| Species | Alpinoceras spiratus (WÄHNER) |
| Author | WÄHNER |
| Group | Alsatiten/Alpinoceraten |
| Horizon | seebachi-horizon |
| Zone | megastoma-Zone |
| Stage | Middle Hettangian |
Description
The casings are evolute and the WQ is highly oval. The inner coils are quite a bit wider than they are tall, but this ratio weakens as they grow. With a diameter of about 50mm, the WQ is almost round.
The external side has a broad, low keel without furrows. The keel is not present in very small specimens, where the external side is evenly rounded.
The low ribs are few in number, they run radially and slightly curved forward over the flanks and disappear near the outer side.
The ribs reach their greatest height on the middle of the flank.
* Description according to Kment (2000), supplemented
Compare
Alpinoceras spiratus is often small in size. The few numerous, almost straight ribs and the low keel without furrows distinguishes the species from other Alpinoceras.
In unfavourable preservation, however, it is often difficult to distinguish it from very similar A. seebachi.
Dimension
Dimensions with D= 50mm (according to Kment):
Nw % v. D: ca. 65%
Wh % v. D: ca. 18%
Wb % v. D: ca. 22%
Literature
- 1894 Arietites spiratus n.f. – Wähner S. 232, Taf, 21.5
- 1994 Arietites spiratus Wähner – Bloos S. 7
- 2000 Alpinoceras spiratus Wähner – Kment S. 204, Taf. 3.7
