| Species | Schlotheimia exechoptycha (WÄHNER) |
| Author | WÄHNER |
| Group | Schlotheimien |
| Horizon | atanatense-horizon |
| Zone | marmoreum-zone |
| Stage | Upper Hettangian |
Description
Schlotheimia exechoptycha is characterised by the extraordinarily strong ribbing: on the inner coils the ribs are simple, strong and separated by wide spaces. They run radially and unusually straight over the flanks to then bend energetically near the external side. The ribs meet externally at an acute angle, leaving a narrow furrow.
From a diameter of about 60 mm, cleavage or switching ribs appear. The sculpture hardly weakens even with age. As can be seen in the photo, in large specimens the main trunks of the ribs can be strongly protruding as bulges near the navel edge, the ribs are strongly weakened on the middle of the flank (where they split), but are again strongly present near the outer side.
The cross-section of the windings is round when young, later highly oval.
* Description according to WÄHNER 1882, supplemented
Compare
The large navel width and the simple ribs refer to the genus Schlotheimia, the strong ribs and the characteristic sculpture when old clearly distinguish the species from Schlotheimia extranodosa and other Schlotheimia. In juvenile specimens, however, the distinction is difficult.
Schlotheimia exechoptycha always occurs together with Angulaticeras trapeziodale and Paracaloceras coregonensis in the younger part of the upper Hettangian.
Dimension
NW % v. D.: ca. 36-38%
WH % v. D.: ca. 36-38%
WB % v. D.: ca. 27-29%
Literature
- 1882 Aegoceras angulatum Schloth. var. exechoptychum n.f. – WÄHNER, S. 166, Taf. 19, 2-3, Taf. 20, 2-4
