| Species | Coroniceras altespinatus (WÄHNER) |
| Author | WÄHNER |
| Group | Arieten |
| Horizon | rotiformis-horizon |
| Zone | rotiformis-zone |
| Stage | Lower Sinemur |
Description
The cross-section of the windings is round at first, but very soon becomes highly oval. The flanks are thickest near the external side and slope slightly convex towards the navel. The slightly retroradiate ribs start near the navel and become highest near the external side in a distinct spine. Towards the keel the ribs quickly become weaker and then extinguish.
Externally, a distinct keel and two shallow furrows can be observed.
Description according to Wähner (1894)
Compare
Although the alpine Coroniceras species all appear quite similar, C. altespinatus is very easy to delimit due to its very large coil width. Nevertheless, it is not excluded that they are extreme forms of the very variable species C. rotiformis.
Dimension
Dimensions with D= 35mm
Nw % v. D: 55%
Wh % v. D: 26%
Wb % v. D: 43%
Literature
1894 Arietites rotiformis Sow.var. altespinatus n.f.– Wähner, S. 220, Taf 52.12
