A new peltaspermaceous pteridosperm from the Upper Permian of the Russian platform

Abstract

The paper focuses on the description of a new species of peltaspermalean pteridosperm Peltaspermopsis polyspermis Naug. sp. nov. The plant remains were collected from the Upper Permian (Tatarian) of northern part of Russia (N. Dvina River Basin). The species is characterized both by reproductive organs (seed bearing discs and their racemose aggregations) and vegetative organs (stems with nodes of seasonal growth interruptions and Pursongia-like lanceolate leaves). The new combination Peltaspermum parvulum (Six tel) Naug. comb. nov. is proposed. General questions concerning Pursongia Zalessky, its taxonomical composition, morphological features and its relationship with Glossopteris are discussed. The species Pursongia amalitzkii Zalessky is described on the base of newly collected material.