Polymorphitidae HAUG, 1887










Family Polymorphitidae

The various species belonging to this family are evolute and of serpenticone form. Their ornamentation consists of simple ribbing. The origin of Polymorphitidae is probably in Eoderoceratidae.

Vertical distribution: Sinemurian - lower Pliensbachian.

Horizontal distribution : cosmopolitan

The material found in the lower Pliensbachian deposits of the department Cher belongs to two subfamilies : Acanthopleuroceratinae ARKELL, 1950 and Polymorphitinae HAUG, 1887.

Platypleuroceras sp Ø 46 mm, a rare genus in southern Berry

Genus Platypleuroceras

This genus contains ammonites with heavy oval or subquadrangular section.The evolute shell is often ornated with simple ribs and a double line of tubercles.

Uptonia jamesoni (Sow.) Ø 18 mm inner whorls
Uptonia bronni (Roe.) Ø 23mm

Genus Uptonia

The evolute ammonites of the genus Uptonia have high and compressed whorls. Simple and dense ribs, cover regularly their shell and form a chevron on the venter. In the inner whorls, small tubercles are visible.

Genus Tropidoceras

Forms of significant size, evolute in the inner whorls, becoming more involute with the age. The weak and flexuous ribbing becomes coarser on the last whorls. It is often accompanied by a fine secondary ribbing on the ventral area.

Acanthopleuroceras cf. carinatum (Quenst.) Ø 40 mm
Acanthopleuroceras gr. arietiforme (Opp.) Ø 27mm

Genus Acanthopleuroceras

It contains large ammonites, strongly evolute. Simple ribbing, sometimes forming a chevron on the venter, ornate the shells. They are accompanied or not by thorny tubercles.The section is most of the time subrectangular. The ventral area often has a more or less blunt keel

Acanthopleuroceras actaeon (d'Orb.) Ø 30 mm
Acanthopleuroceras alisiense (Rey.) Ø 40mm
We are seeking.....
Tropidoceras sp.
Uptonia confusa (Quenst.)
Uptonia regnardi (d'Orb.)
Uptonia lata (Quenst.)
Acanthopleuroceras maugenesti (d'Orb.) Ø 63 mm
Acanthopleurocares maugenesti transient valdani (d'Orb.) Ø 76mm
Acanthopleuroceras valdani (d'Orb.) Ø 66mm