Palaeoscolecid sclerites from the Upper Cambrian Mila Formation of the Shahmirzad section, Alborz Mountains, northern Iran

Abstract

Phosphatic, discoidal sclerites with prominent nodes on the external surface have been found in Upper Cambrian inter-reef calcareous grainstone of the Mila Formation in the Shahmirzad section, Alborz Mountains, northern Iran. This is the first record of a palaeoscolecid worms from Iran. Isolated sclerites demonstrate a complex ornamentation characteristic of the widely known species Hadimopanella oezgueli GEDIK 1977 and are interpreted as dermal plate elements of Palaeoscolecida. Hadimopanella sclerites are known outside Iran from adjacent areas including Turkey, Kirgizia and China and from the more distant continents of Australia, Antarctica, Siberia, Baltica (Sweden, Estonia) and peri-Gondwanan Europe (Spain). The Iranian palaeoscolecid worms were probably infaunal constituent of bentic marine community in inter-reef environment. The utility of isolated sclerites for Cambrian biozonation is stillrather low.