Annelid from the Neoproterozoic Doushantuo Formation in Northeastern Guizhou, China

Wenghuiia jiangkouensis gen.et sp.nov.,characterized by modern annelid taxonomy in morphology and functional biology,is found in black carbonaceous shale from the Neoproterozoic Ediacaran Doushantuo Formation(about 555 Ma)near Wenghui,Jiangkou,northeastern Guizhou Province.The elongate,cylindrical body is composed of many homologous metameres with a true coelom and coelomic pouches.The mouth is at the front of the first segment and the anus at the end of body.A long 11~(th)or 12~(th)segment is probably functionally for procreation,being a clitellum.There are parapodia on the venter of the segments from the rear of the second segment to the front of the clitellum.The setae on all metameres,on the parapodia,and around the anus,differ.In the centre of body,a line probably represents the alimentary canal passing through the body from mouth to anus. A closed vascular system consists of a dorsal vessel at least.W.jiankouensis might represent the oldest discovered 'modern' annelid but it is not a primitive type.It lived on the depositional surface of a shallow sea with an environment of calm-water and abundant light.