Asselian–Sakmarian (Lower Permian) Brachiopod Zonation of the Verkhoyansk Region, Northeast Russia

As a result of study of new collections of brachiopods, a zonal scheme of the Asselian–Sakmarian deposits in the Verkhoyansk region based on the phylogenetic development of Jakutoproductus is elaborated. The J. verkhoyanicus Zone is distinguished in the Khorokytian Horizon; in some sections, it may be divided into the beds with J . talchanensis and beds with J. lenensis . The succession of the J. insignis, J. terechovi, and J. rugosus zones is established in the Echian Horizon and provides direct correlation with the Kolyma–Omolon region. The index species of all brachiopod zones of the Asselian–Sakmarian interval in the Verkhoyansk region are described: Jakutoproductus verkhoyanicus (Fredericks), J. insignis Abramov et Grigorjeva, J. terechovi Zavodowsky, and J. rugosus Ganelin.