Now, a research team from Virginia Tech in the United States and Nanjing Institute of Geology and Paleontology in China has discovered uniquely well-preserved fossils form from 550 million year old rocks of the Ediacaran Period. Shuhai Xiao, geoscientist from Virginia Tech, with Bing Shen, a Virginia Tech graduate student, and Chuanming Zhou, Guwei Xie, and Xunlai Yuan, all of the Nanjing Instititue of Geology and Paleontology, report in the Proceedings of the National Academy of Sciences (PNAS) the discovery of these unusually preserved fossils which reveal unprecedented information about the body construction of macroscopic organisms more than half billion years ago. The article has been published in the PNAS Online Early Edition the week of July 11 - 15, 2005.
Ediacara fossils, named after Ediacara Hill in the Flinders Ranges of South Australia where such fossils are best known, are some of the oldest fossils with large body size and complex morphology. "Present in rocks ranging from 575 to 540 million years in age, these fossils provide the key to understand the prelude to the Cambrian Explosion when animals with skeletons and familiar morphologies began to bloom about 540-520 million years ago," Xiao said, "However, classic Ediacara fossils are mostly preserved in sandstone, and the coarse sand grains limit how much we can learn about the fine-scale morphologies of these fossils."
Partly because of this limitation, scientists cannot agree on the fine-scale anatomy of Ediacara organisms and have been debating for decades their relationships with animals and other macroscopic life forms. Traditionally, Ediacara organisms are thought to