Fig. 3

The anomalous individuals of Peltoceras athleta from the Upper Callovian (P. athleta Zone) of Méron. Specimens with lappets (A: n° mbe.9305; B: n° mbe.1401; PYB collection) showing a typical macroconch ornamentation on the phragmocone, passing to a microconch-like morphology approaching the aperture. White dots indicate the end of the phragmocone. Scale bar is 10 mm