Gatunek typowy
Posttornoceras balvei Wedekind, 1910 from the mid Famennian Platyclymenia annulata Zone of the Rhenisch Slate Mountains.

Opis

Diagnosis. — Suture with pointed flank lobe and angular or pointed dorsolateral lobe.

Remarks. —  Exotornoceras was proposed for the most primitive members of the lineage with a relatively shallow dorsolateral lobe. The difference seems too minor and continuity too apparent to make this taxonomical subdivision practical. There was suggested that this lineage was rooted in Gundolficeras, which is supported by the data from the Holy Cross Mountains.
The suture of Posttornoceras is similar to that of Sporadoceras, but these end-members of unrelated lineages differ rather significantly in the geometry of the septum. In Posttornoceras the parts of the whorl in contact with the preceding whorl are much less extensive, the dorsolateral saddle is much shorter and of a somewhat angular appearance. This is obviously a reflection of the difference in the whorl expansion rate between the tornoceratids and cheiloceratids.

Synonimy

Zasięg czasowy

Literatura

Dzik, J. 2006. The Famennian "Golden Age" of conodonts and ammonoids in the Polish part of the Variscan sea. Palaeontologia Polonica 63, 1-359.