| Species | Eolytoceras rohrbachensis Kment |
| Author | KMENT |
| Group | Lyctoceraten |
| Horizon | rotiformis-horizon |
| Zone | rotiformis-zone |
| Stage | Lower Sinemur |
Description
The species is small-bodied, the winding cross-section is round at first, but becomes oval as it grows. The umbilical edge is tightly rounded, the umbilical drop is steep and the flanks are convex.
On the inner coils, numerous, simple and low ribs can be observed, which become increasingly fine and s-shaped. Near the navel they begin retroradiate, bend forward at the edge of the navel and disappear in the middle of the flank. There, only growth stripes can be observed on the shell crossing the external side. It looks like the main ribs split into several lines.
The stone core is basically smooth, but there are S-shaped constrictions that follow the course of the ribs.
* Description according to Kment (2021)
Compare
Eolytoceras from the upper Hettangian/lower Sienmurian area is repeatedly described in the literature. The small increase in thickness distinguishes the genus from Analytoceras articulatum, which occurs earlier (atanatense horizon).
An Eolytoceras sp. has been described from the subsalinarius horizon (Kment 2000), which could be a close relative.
Eolytoceras rohrbachensis is clearly characterised by the distinct ribs on the inner coils and the s-shaped accretion stripes and constrictions on the outer coils.
Dimension
Dimensions with D = 18mm
Nw % v. D: 39%
Wh % v. D: 31%
Wb % v. D: 28%
Literature
- 2021 Eolytoceras rohrbachensis n. sp. – KMENT, S. 279, Abb. 11.7-11.9, 13.8
