The ammonoid recovery after the end-Permian mass extinction: evidence from the Iran-Transcaucasia area, Siberia, Primorye, and Kazakhstan

Abstract

Investigations of the Upper Permian strata in the Iran-Transcaucasia resulted in identification of 32 ammonoid genera. The majority of ammonoids in this collection belong to the order Ceratitida (75%). Among Dzhulfian ceratitid ammonoids representatives of the family Araxoceratidae (Otoceratoidea) are most abundant. The assemblage structure changed radically during latest Permian (Dorashamian) time, bringing a domination of the family Dzhulfitidae. The Induan (Lower Triassic) succession in the Verkhoyansk area provided a few groups of ammonoids which are Palaeozoic in type: families Episageceratidae (Episageceras), Xenodiscidae (Aldanuceras and Metuphiceras), and Dzhulfitidae (Tumpuphiceras) and superfamily Otoceratoidea (Otuceras and Vaviluvites). It demonstrates the survival of ammonoids belonging to these groups the Permian—Triassic (P—T) boundary extinction event and their quick migration to the vast areas of higher latitudes (together with some representatives of the Mesozoic-type families). Induan—O...