Produced by the Population Genetics and Evolution class, Furman University

The Ediacaran: The Doushantuo Formation
The Doushantuo Formation in Guizhou, South China is a 57 km^2, Neoproterozoic lagerstätte; an area containing highly preserved, abundant fossil material currently dated between 635-551 million years old (Condon et al. 2005). Discovered in the late nineties, it is of particular interest because this date falls before the Cambrian Explosion, possibly spanning 90% of the Ediacaran period (Condon et al. 2005). The formation includes what may be embryos and eggs of different animals, though that conclusion is still under debate as some scientists contend that these small fossils may be other organic or inorganic formations (Raff et al. 2006). Raff et al. (2006) argue that the size of an embryo has little to do with how well it may be preserved, so the Doushantuo Formation may indeed contain fossil evidence of some of the very first bilaterians. The evolution of complex animals may have been fostered by the rise in oxygen at this time (McFadden et al. 2010). The site contains a variety of fossils, including marine algae, cnidarians, protists, bacteria, archaebacteria, and the oldest recorded sponges (Clowes 2004). A possible factor in the high quality of the fossils (some can even be studied at the cellular level and have been shown to have properties very similar to some modern plants) is that the organisms may have been buried alive and exposed to high levels of dissolved phosphate (Clowes 2004). All in all, the Doushantuo Formation is certainly one of the most important finds in paleontology and evolutionary biology.

Page by Will Towler
Putative fossil embryos from the Doushantuo Formation; note possible bilateralism. Field view approx. 0.15 mm width. Photo from PhysOrg.com.
Clowes C. 2004. Doushantuo Formation. www.peripatus.gen.nz. Accessed Jan 24, 2010.

McFadden KA, Huang J, Chu X, Jiang G, Kaufman AJ Zhou C, Yuan X, Xiao S. 2008. Pulsed oxidation and biological evolution in the Ediacaran Doushantuo Formation. PNAS 105: 3197-3202.

Raff E, Villinski J, Turner F, Donoghue P, Raff R. 2006. Experimental taphonomy shows the feasibility of fossil embryos. PNAS 103: 5846-5851.

Condon D, Zhu M, Bowring S, Wang W, Yang A, Jin Y. 2005. U-Pb ages from the Neoproterozoic Doushantuo Formation, China. Science 308: 95-98.