Abstract:

The Weng'an biota, a well-preserved phosphatized fossil Lagerstatten, from the Upper Member of the Neoproterozoic Ediacaran Doushantuo Formation at Weng'an County, Guizhou Province (E107°23′03″, N27°00′56″), including various multicellular organisms, has been attached to the study of early metazoan and embryos of metazoan. In the horizon of the lower of the Weng'an biota yielded and under it, three trace fossils are found: Wenganichnus nanbaoensis(ichnogen.et ichnosp.nov.), a slight curving tube with liner and lunate backfill-structure; Doushantuoichnus curvatus(ichnogen.et ichnosp.nov.), an epichnion bearing a central groove with small across ridges and some leafshaped bulges on the both sides of the central groove; ?Planolites ichnosp., a long linear-form ichnofossil wandering on the bedding surface and differing from the host rock. The characteristics of the trace fossils show they are produced by animal, no sedimentary structures. Their makers may be bilateral symmetric worm-form animals that could have fore/hind and dorsal/ventral differentiation and could be ability to move along an orientation. The egg and embryo fossils from the Weng'an biota may be oviposited by soft-body metazoan that is uneasily preserved. The eggs and embryos, in shallow-water with a high-energy environment, were conveyed and deposited in seafloor together with sediments, and then the dormant eggs and embryos buried in sediments are preserved.

Key words: trace fossil, metazoan, Weng'an biota, Doushantuo Formation, Ediacaran, Weng'an, Guizhou