Late Barremian Heteroceratidae Hyatt 1900 (ammonoidea), from the Sarcheshmeh Formation (Koppeh-Dagh Basin, Northeast Iran): biostrartigraphy and paleobiogeoraphy

Representative ammonites of the Family Heteroceratidae have been studied in this paper. The following forms are recorded from the Koppeh-Dagh Basin: Heteroceras cf. colchicus Djanelidze, Heteroceras spp., Martelites cf. tenuicostatus (Kakabadze), Martelites securiformis (Simonovich, Bastevich and Sorokin), Martelites cf. tinae (Eristavi), Martelites sp.1, Martelites sp. 2, Argvethites sp., Imerites sparcicostatus Rouchadze and Paraimerites sp. A Late Barremian age is suggested for beds containing these forms. The Heteroceras sp. and Martelites securiformis Zones are proposed for the Upper Barremian Sub-Stage in the Koppeh-Dagh Basin. Dispressal paleobiogeographic pattern of Heteroceratidae family and relation between Koppeh-Dagh basin and surrounding basin have been discussed during Late Barremian.