Species | Psiloceras strongolum LANGE |
Author | LANGE |
Group | Psiloceraten |
Horizon | strongolum-horizon |
Zone | tilmanni-zone |
Stage | Lower Hettangian |
Description
The case is involute, with the inner coils being less involute than the outer ones (see dimensions). On the innermost 1-2 coils a nodule stage is formed with 7 to 8 strong nodules per coil. This stage passes into quite strong, blunt and strongly recurved ridges. After two to three turns the ribs flatten and the body is largely smooth. Occasionally, little raised ribs/ a striation to the end of the outermost turn can be observed. The external side is rounded, the flanks flatly curved. The umbilical drop is narrowly rounded and the umbilical wall oblique. The lobe line is strongly branched. The suspensory lobes are strongly set back.
For a detailed description of this species, see VON HILLEBRANDT & KMENT (2015).
Compare
P. strongolum has a greater width of coils than P. calliphyllum, the cross-section of the coils is more rectangular. The ribs are stronger and more recurved. The microconch of P. strongolum and P. calliphyllum are very similar and cannot really be distinguished yet. (Description in VON HILLEBRANDT & KMENT 2015).
P. strongolum occurs en masse at the base of the Calliphyllum bed, still below P. calliphyllum.
Dimension
Literature
- aff. 1895 Aegoceras calliphyllum Neum. – WÄHNER, S. 32, 43, Taf.6, fig. 5.
- 1952 Psiloceras (Paraphylloceras) strongolum sp. n. – LANGE, S. 117, Taf. 14, figs. 6, 7; text-fig. 2, figs. 38-43.
- 1988 Psiloceras calliphyllum NEUMAYR. – VON HILLEBRANDT, S. 59, Taf. 1, fig. 1.
- 2015 Psiloceras strongolum LANGE.- VON HILLEBRANDT & KMENT