Lower Pliensbachian dimorphic pairs

Faune

Dactylioceratidae

Couples

Eoderoceratidae

Liparoceratidae

Oxynoticeratidae

Juraphyllitidae

Lytoceratidae

Polymorphitidae

Sexual dimorphism in lower Pliensbachian ammonites

Several cases of sexual dimorphism in carixian ammonites are shown on this page. Three families are concerned : Lytoceratidae, Liparoceratidae and Dactylioceratidae. They often exhibit a great size difference.
Liparoceras M & Metacymbites m
Lytoceras M & Derolytoceras m (not found)

Microconch (m) :

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

When complet, the microconch often has lappets at the aperture.
Coeloceras M & "Polymorphites" m

Macroconch (M) :

The bigger shell of the dimorphic pair, with simple aperture, is called macroconch. It is probably the female.