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New investigations on a Late Devonian outcrop near Esfahan (Chahriseh section) revealed new data about the Polygnathus bouckareti, Polygnathus communis group and genus Clydagnathus. The feature differentiation related to the recovered species shows the exigency of a few changes in the age and variety of morphotypes of P. communis group. Some identified species in this paper are: Polygnathus communis communis, P. communis mugodzharicus, P. bouckaerti, P. pomeranicus, P. lanceolus, P. inconcinnus, Icriodus alternatus alternatus and I. cornutus. By considering the conodont associations, changes in the age of P. bouckaerti and P. communis mugodzharicus are the other results. In addition, two morphotypes of P. communis mugodzharicus and more detailed explanation of
P. communis group are presented.