Oppeliidae BONARELLI, 1894













Family Oppeliidae

The expansion of Oppelidae begins with the middle Jurassic to finish with the Cretaceous. The representatives of this family have a rather compressed shell (oxycone) and an ornamentation mainly made up of falcoid primary ribbing. The ammonites which belong to this group have a very vast geographical distribution which only excludes the boreal areas. In the Bathonian of the southern Paris basin, Oppeliidae are commun, except the genus Trimaginia.

Oxycerites aspidoides (Opp.) Ø 118 mm
Oxycerites seebachi (Wetz.) Ø 58 mm
Oxycerites limosus (Buck.) Ø 45 mm

Genus Oxycerites

This involute ammonite has an oxycone section and a keel. The ornementation first consists in falcate ribbing ; then the shell becomes smooth. The aperture is always simple.

We are seeking.....
Oxycerites pygmaea (Ark.)
Oxycerites fallax (Guér.) Ø 70 mm
O. (Oecotraustes) bomfordi (Ark.) Ø 35 mm

Genus Oecotraustes

In this genus you can find small and moderately involute species with falcate ribs. Some of them had a median groove and an aperture with small lappets. Oecotraustes and Oxycerites may be a dimorphic pair.

O. (Oecotraustes) nivernensis (de Gross.) Ø 52 mm
O. (Oecotraustes) decipiens (de Gross.) Ø 42 mm
O. (Oecotraustes) cf. bradleyi (Ark.) Ø 42 mm

Genus Eohecticoceras

Ammonite with discoidal shell, involute section, strong falcate ribbing and gentle tubercles on the venter.

Eohecticoceras primaevum (de Gross.) Ø 62 mm
O. (Paroecotraustes) cf. angustoides (Elmi) Ø 38 mm
Trimarginia sinaitica (Ark.) Ø 58 mm

Genus Trimarginia

This is a compressed and strongly involute ammonite with tricarinated venter. Its ornementation is the same as Oxycerites. Trimaginia is a tethysian genus.