Middle and Upper Cambrian polymerid trilobites and biostratigraphy, Fenghuang area, Western Hunan Province, China

Middle and Upper Cambrian polymerid trilobite faunas are described from the Fengmuping, Laochatian, Tingziguan and Jiantang Formations of the Haichongkou section in the Fenghuang area, Western Hunan Province, China. A total of 32 species belonging to 29 genera and subgenera are described, including Trigocephalus gen. nov. and Tuojiangella gen. nov., and 7 new species (Corynexochus hunanensis sp. nov., Onchonotellus fenghuangensis sp. nov., Trigocephalus trigoformis gen. et. sp. nov., Tuojiangella tuojiangensis gen. et. sp. nov., Pseudoyuepingia jiantangensis sp. nov., Koldinioidia (Liriamnica) labakouensis sp. nov. and Ivshinaspis formosa sp. nov.). Four trilobite assemblages and their correlations with trilobite faunas of China and overseas are outlined.