| Species | Pseudotropites ultratriasicus (CANAVARI) |
| Author | CANAVARI |
| Group | Arieten |
| Horizon | subsalinarius-horizon |
| Zone | rotiformis-zone |
| Stage | Lower Sinemur |
Description
Quite strong, retroradiate ribs begin at the suture, ending in a spine or knot approximately at the middle of the flank, where it is highest. From this knot again - two or three - weak ribs begin, which run in a wide arc forward and end in the little raised secondary keels. If well preserved, a corrugation of the keel and the secondary keels caused by these ribs can be observed. The keel itself and the furrows are weak and -according to Wähner- developed very late. No keel can be observed on the inner coils.
The cross-section of the coils is extremely high oval, the greatest width is approximately on the middle of the flank. The navel is sunken like a funnel.
* Description according to Wähner (1894), supplemented
Compare
Umbilical width and coil height correspond to those of "Arietites" ligusticus or A. ligusticoides. The width of the coils, however, is many times greater! A confusion is therefore not possible. This shape of the shell is typical for some tropites in the Hallstatt limestones (Triassic). Hence the name of the genus. However, a relationship is impossible.
Perhaps it would make sense to place A. ligusticus and A. ligusticoides also in the genus Pseudotropites.
P. ultratriasicus is extraordinarily rare. Only one specimen was available to Wähner; only one has been known from our area so far (see illustration).
Dimension
Dimensions with D= 25mm (according to Wähner):
Nw % v. D: ca. 39%
Wh % v. D: ca. 36%
Wb % v. D: ca. 80%
Literature
- 1894 Pseudotropites ultratriasicus Canav. – Wähner, S. 237, Taf. 54.1
