| Species | Psiloceras tibeticum Yin et al. |
| Author | YIN |
| Group | Psiloceraten |
| Horizon | tibeticum-horizon |
| Zone | tilmanni-zone |
| Stage | Lower Hettangian |
Description
The body is very evolute, the winding cross-section round to oval. The umbilical edge is rounded and the umbilical drop short and steep. The distinct but low ribs are quite wide on the outer coil and slightly sloping back. They start at the umbilical edge, have the greatest height on the middle of the flank, become weaker as they bend forward and disappear towards the venter.
A nodule stage can be observed on the innermost coils.
The ribbing can be somewhat irregular overall; the spaces between the ribs are not always the same size.
* Description according to Kment (2021)
Compare
Psiloceras tibeticum can be clearly identified by its very large navel width.
In Waehneroceras waehneri there is a very large variability in the navel width , forms with 50% at a diameter of 29mm occur. In condensed sequences the two can be present embedded together. The ribbing is much stronger in Waehneroceras and the ribs higher, less blunt.
The blunt ribs are reminiscent of Caloceras, whose species, however, only occur higher up in the profile.
Dimension
Dimensions with D= 42mm
Nw % v. D: 54%
Wh % v. D: 24%
Wb % v. D: 20%
Literature
- 2007 Psiloceras tibeticum sp. nov. – YIN et al., p. 726, pl. 2, figs. 1–8, text-fig. 9, pl. 3.
- 2021 Psiloceras tibeticum YIN et al., – KMENT, S. 243, Abb. 5.2-5.5
