Species | Psiloceras angulocostatum VON HILLEBRANDT & KMENT |
Author | KMENT VON HILLEBRANDT |
Group | Psiloceraten |
Horizon | angulocostatum-horizon |
Zone | tilmanni-zone |
Stage | Lower Hettangian |
Description
So far, only two specimens have been found, in which only the living chambers are well preserved. The phragmocones were firmly fused to the rock, so that no statements could be made about nodule stage or lobule line. The shells are quite evolute, the coil cross-section oval. The largest coil width is observed on the middle of the flank. The umbilicus is relatively flat, the umbilical drop narrowly rounded and the umbilical wall steep. Characteristic are the blunt and broad retroradiate ribs, which become broader on the outer flank and bend slightly forward before extinguishing (15 on the last turn of the phragmocone). On the living chamber the ribs are clearly angular.
* Description according to VON HILLEBRANDT & KMENT 2015, supplemented
Compare
This type of ribbing is also present (after the nodule stage) on the inner convolutions of Psiloceras spelae tirolicum HILLEBRANDT & KRYSTYN, sometimes beyond. However, P. angulocostatum is much more evolved than P. spelae. In the latter the largest width of the coils is also near the navel, whereas in P. angulocostatum it is on the middle of the flank. P. angulocostatum was found several banks below Calliphyllum Bed.
Dimension
Literature
- 2015: Psiloceras angulocostatum n. sp. VON HILLEBRANDT & KMENT
- 2021 Psiloceras aff. angulocostatum HILLEBRANDT & KMENT – KMENT S. 241, Fig. 5.1