Permian basinal ammonoid sequence in Nanpanjiang area of South China—possible overlap between basinal Guadalupian and platform-based Lopingian

Abstract

AbstractThe Permian pandemic ammonoids in Nanpanjiang Basin (41 genera, including two new generaGlenisterocerasandFusicrimites, and 56 species, including 21 new species) are systematically described and/or discussed. New species described in this paper areAgathiceras sequaxiliraen. sp.,Akmilleria parahuecoensisn. sp.,Aristoceras liuzhaiensen. sp.,Bamyaniceras nandanensen. sp.,Bamyaniceras yangchangensen. sp.,Bransonoceras longyinensen. sp.,Difuntites furnishin. sp.,Emilites globosusn. sp.,Eoaraxoceras spinosain. sp.,Eumedlicottia kabiensisn. sp.,Fusicrimites nanpanjiangensisn. gen. n. sp.,Glenisteroceras sidazhaiensen. gen. n. sp.,Metaperrinites shaiwaensisn. sp.,Miklukhoceras guizhouensen. sp.,Neocrimites guizhouensisn. sp.,Neopronorites leonovaen. sp.,Popanoceras ziyunensen. sp.,Properrinites gigantusn. sp.,Stacheoceras shaiwaensen. sp.,Svetlanoceras uraloceraformisn. sp., andSynartinskia meyaoensen. sp. A relatively complete Permian basinal ammonoid sequence with six zones has been newly recognized in South China, in ascending order,Properrinites gigantus-Svetlanoceras serpentinum,Svetlanoceras uraloceraformis-Prothalassoceras biforme,Popanoceras kueichowense-Medlicottia orbignyanus,Metaperrinites shaiwaensis-Popanoceras ziyunense,Waagenocerassp.-Propinacoceras beyrichi, andEoaraxoceras spinosai-Difuntites furnishi. The upper three zones are close to being duplicated from the Permian of Las Delicias, Coahuila, Mexico and west Texas, USA; while the lower three zones compare well to those of the Lower Permian in South Urals. TheEoaraxoceras-Difuntitesassemblage, as an index fauna of the upper Capitanian in Coahuila, has been found from the Claystone (3rd) Member of the Shaiwa Formation with the commonly accepted Lopingian stratigraphic age. The updated Permian ammonoid biostratigraphy in South China reveals a possible overlap between the basinal Guadalupian from North America and the platform-based Lopingian from South China.