The World’s second oldest strophomenoid-dominated benthic assemblage in the first Dapingian (Middle Ordovician) brachiopod fauna identified from Iran

Abstract

Rocks previously mapped as Devonian at Gerd-Kuh in the Eastern Alborz Mountains of Iran have yielded Middle Ordovician faunas including the brachiopods described here, the first rhynchonelliform brachiopods of Dapingian age ever described from Iran. The shells described are defined as a new Dirafinesquina Benthic Association, and which is the second oldest strophomenoid-dominated assemblage from anywhere in the World. There are six brachiopods, three of which are newly named as the strophomenoid Dirafinesquina antiqua sp. nov., the orthoid Zhanorthis gerdkuhensis gen. et sp. nov., and the porambonitoid Eoporambonites raziabadensis sp. nov.