中国科学院南京地质古生物研究所机构知识库

Two new species of Pseudopetigurus are described from northern Hunan Province, China. P. deprati n. sp. is abundant in the upper Zitai Formation (upper Arenig) of Shuanghong, Baiyun, Shimen County, and P. expansus n. sp. occurs throughout the Jiuxi Formation (Arenig - lower Llanvirn) of Panjiazui, Taoyuan County. These formations represent outer shelf facies from the Jiangnan Transitional Belt of the South China Plate, close to the southeast margin of the Yangtze Platform. Both P. deprati and P. expansus show similarities to Upper Ordovician species of Pseudopetigurus recorded from South China. Other species of Pseudopetigurus are known almost entirely from cranidia, but pygidia and librigenae are also described for both new species, and the first known hypostome assigned to the genus is described for P. expansus. These two species are ecologically important members of offshore trilobite faunas during the Arenig - Llanvirn and define the outer shelf Pseudopetigurus Association of South China. Despite being a deep-water genus, Pseudopetigurus is biogeographically restricted to the western margin of the Gondwanan craton and neighbouring regions of Baltica.