Bathonian dimorphic pairs

Fauna

Lytoceratidae

Pairs

Pseudoperisphinctidae

Parkinsoniidae

Clydoniceratidae

Morphoceratidae

Phlycticeratidae

Sphaeroceratidae

Oppeliidae

Lissoceratidae

Phylloceratidae

Samples of sexual dimorphism in bathonian ammonites

The dimorphic pairs of the lower Bathonian stage of Nevers belong to the following families : Pseudoperisphinctidae, Sphaeroceratidae and Morphoceratidae.

Microconch (m) :

This term is used for the smaller shell of the pair, probably the male.

When complet, the microconch often has lappets at the aperture.

Macroconch (M) :

The bigger shell of the dimorphic pair, with simple aperture, is called macroconch. Probably it is the female.
A. (Asphinctites) M & A. (Polysphinctes) m

M. (Morphoceras) M & M. (Ebrayiceras) m
C. (Polypectites) m & C. (Cadomites) M

P. (Siemiradzkia) m & P. (Procerites) M
L. (Lobosphinctes) M & L. (Planisphinctes) m