Species Schreinbachites retroversicostatus (CANAVARI)
Author
Group
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Stage
Description

After smooth inner coils, a clear ribbing sets in. The ribs are initially bulging and straight, later slightly convexly curved and more or less clearly retroradiate. A nodule stage (comparable to many other alpine species) is not present. The bending of the ribs becomes more pronounced with age. They start at the suture, run over the flank and end in the secondary keels.
This ribbing is only regular on the inner coils, characteristic is an extremely "restless" sculpture: seemingly randomly stronger and weaker ribs occur, the distance of the ribs to each other varies, also rib unions are possible.
A raised keel, often projecting beyond the coils, accompanied by deep furrows, is developed very early. In larger shells, secondary keels are then developed; their appearance can be seen very well in the illustrations.
The cross-section of the windings is always much wider than high, which is quite typical for this species. The largest coil width is usually in the middle of the flank. Only in very large specimens can the ratio Wh:Wb become 1:1.
BLOOS gives a detailed discussion of the genus and species, including the loben line, which is very simplified in Schreinbachites and thus similar to Vermiceras and Gyrophioceras.

* Description according to Bloos (1994) and Kment (2000), supplemented

Compare

Compared to Vermiceras (Epammonites) cordieri, the secondary keels are less sharply marked and the ribbing is completely different.
In small specimens with almost regular ribbing there is a very high risk of confusion with other small Arietitidae (e.g. Vermiceras (Gyrophioceras)). However, the very large width of the coils and the irregular ribbing is then the main criterion for finding the species. Alpinocerats with a similar cross-section like A. salinarius or A. perspiratus have a less strongly developed keel and a more complicated lobed line.

Dimension

Dimensions with D= 55mm:
Nw % v. D: ca. 53%
Wh % v. D: ca. 24%
Wb % v. D: ca. 31%

Literature
  • 1882 Arietites retroversicoststus n.sp. – CANAVARI S. 177, Taf. 20.13-14
  • 1890 Arietites anastreptoptychus n.f. – WÄHNER S. 243, Taf. 46.3-5
  • 1994 Schreinbachites retroversicoststus Canavari – BLOOS S. 46, Taf. 4.18, Abb. 11,13,14
  • 2000 Schreinbachites retroversicoststus Canavari – KMENT S. 208, Abb. 45
Images

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