| Species | Discamphiceras atanatense WÄHNER |
| Author | WÄHNER |
| Group | Psiloceraten |
| Horizon | atanatense-horizon |
| Zone | marmoreum-zone |
| Stage | Upper Hettangian |
Description
D. atanatense differs from D. kammerkarense by the even narrower umbilicus and the weaker sculpture. An essential difference is the lobe line: the lateral saddle is lower than the external saddle, which is reversed in other discamphicerates.
After a clear nodular stage, low, irregular, s-shaped ribs appear. Switch ribs are frequent, their arrangement absolutely irregular. The faint ribbing is still quite visible even on larger specimens. A regular corrugation may occur on the outer side, which is probably a remnant of rib unions (see illustration).
D. atanatense can grow very large.
* Description according to WÄHNER (1883), supplemented
Compare
D. atanatense has weaker and more irregular ribs than D. kammerkarense. It occurs very frequently in the younger part of the marmoreum fauna. Where the deposits are somewhat thicker, D. atanatense is clearly above S. donar pachygaster or A. marmoreum.
Dimension
Dimensions at D= 88mm (according to Wähner):
Nw % v. D: ca. 23%
Wh % v. D: ca. 44%
Wb % v. D: ca. 23%
Literature
- 1883 Aegoceras Atanatense n.f. – WÄHNER S. 118, Taf. 14.1
- 2000 Discamphiceras atanatense Wähner – Kment S. 197, Taf. 14.1
