Original paper

The chronostratigraphical record of Didayilamellaptychus (Lamellaptychi, Ammonitina)

Vašíek, Zdeněk; Janssen, Nico M.M.; Klein, Jaap


The genus Didayilamellaptychus includes the last representatives of calcitic ribbed aptychi in the evolution of the family Lamellaptychidae. This fact is documented in the present study focusing on lamellaptychi collected together with ammonites from Lower Cretaceous localities in the south-east France and Spain. Eight specimens are described in the paper. The oldest representatives of Didayilamellaptychus appear close to the Lower/Upper Valanginian boundary. Their ribs converge in an arch-shape manner towards the apex. Representatives with angularly inflected ribs prevail in the Hauterivian. The here described species have an extensive occurrence in the Mediterranean area. Only one of them (D. andrusovi) has been found so far in the Western Carpathians exclusively.


didayilamellaptychuslamellaptychimediterranean areavalanginianhauterivian