| Species | Alsatites proaries (NEUMAYR) |
| Author | NEUMAYR |
| Group | Alsatiten/Alpinoceraten |
| Horizon | curviornatum-horizon |
| Zone | megastoma-Zone |
| Stage | Middle Hettangian |
Description
The very wide-billed species has a circular WQ and tends to form a keel in very large shells by slightly sharpening the external side. Furrows may be indicated. The diameter at which the keel begins to form is very variable.
The ribbing is particularly characteristic: the folds begin retroradiatively at the suture, run in an arc open to the front over the flanks and meet the ribs of the other side externally at an acute angle, much attenuated. The ribs are built asymmetrically: they slope gently towards the rib interspace in front, but steeply towards the back. Wähner describes this as a "roof tile-like appearance". In addition, the ribbing is very irregular: the width of the spaces varies. Likewise, the thickness of the ribs can vary: there are specimens with particularly fine sculpture. This can be observed particularly at the Fonsjoch locality. Perhaps these are the oldest forms.
Wähner describes this species very comprehensively and in detail - he had numerous specimens available.
* Description according to Wähner (1884), supplemented
Compare
The characteristic ribbing in combination with the very large navel width make the identification of Alsatites proaries very easy.
Only the variants A. proaries var. distans, var. triphyllum and var. lataecarinatus, separated by Wähner, can be quite easily confused.
There is a great similarity to Laqueoceras sublaqueus at small diameters, which Wähner discusses in great detail.
Dimension
Dimensions at D= 140mm (according to Wähner):
Nw % v. D: ca. 70%
Wh % v. D: ca. 16%
Wb % v. D: ca. 16%
Literature
- 1879 Arietites proaries n.f. – Neumayr S. 37, Taf. 7.1-2
- 1884 Arietites proaries Neum.- Wähner S. 217, Taf, 28.1, 29.1-4, 30.5-11
- 1952 Proarietites proaries (Neumayr) – Lange S. 147
- 1963 Arietites (Alsatites) proaries Neumayr – Blind S. 100, Taf. 3.6
