Upper Devonian (Famennian) and Lower Carboniferous (Tournaisian) ammonoids from western Junggar, Xinjiang, northwestern China—stratigraphy, taxonomy and palaeobiogeography

Abstract

Seven ammonoid levels/assemblages are recognised in the Devonian (Famennian) and Carboniferous (Tournaisian) of the northwestern Junggar Basin, Xinjiang, northwestern China. Eleven genera and 20 species, including six new species (Becanites sp. nov., Protactoclymenia junggarensis sp. nov., Prot. magna sp. nov., Cyrtoclymenia? parallela sp. nov., Sporadoceras impressum sp. nov. and “Mimimitoceras” transiens sp. nov.) are described from the Hongguleleng and Heishantou formations in the Bulongguoer, Hebukehe, Emuha and Hashatu sections. The first assemblage is characterised by Platyclymenia subnautilina (Sandberger), Prionoceras frechi (Wedekind) and Sp. impressum sp. nov.