be related to such animals as jellyfishes and worms. Other scientists, however, believe that they may be plants or fungi. Twenty years ago, however, Adolf Seilacher, a paleontologist now retired from University of Tubingen (Universität Tübingen) and Yale University, argued that many Ediacara organisms were built of tube-like elements and are only distantly related to living animals. "But direct observation of the hypothesized tube-like elements has been difficult because such tubes tend to be deflated and squashed prior to their preservation in sandstones," Xiao said.
This may change with the new discovery of Ediacara fossils from fine-grained limestone of the Dengying Formation in South China by Xiao and his collaborators. "The Ediacara fossils from China were not deflated before they were incorporated in the rock," said Shen, "instead, they are preserved three-dimensionally in the rock." Using serial thin sectioning techniques, Shen and Xiao cut the decimeter-sized fossils into many paper-thin slices and looked at them under a microscope. They saw organic remains of millimeter-sized tubes that were the building blocks of the Ediacara fossils from China. Their discovery thus directly confirms Seilacher's hypothesis.
The new fossils also help to refine the Seilacher hypothesis. Seilacher originally hypothesized that Ediacara tubes had closed ends and were filled with cytoplasm, or cell contents. The fossils from China, however, appear to have an open end that is connected with the external environment. Thus, Xiao and his colleagues infer that the tubes of their Ediacara fossils were probably not filled with cytoplasm.
Ediacara organisms had no shells or bones. How could such soft and delicate organisms be preserved in rocks? Working with Geosciences Professor Fred Read at Virginia Tech, Geology Professor Guy Narbonne at Queen's University, and paleontologist James Gehling at South Australia Museum, Xiao and his colleagues carefully examined Page: 1 2 3 Related biology news :1
. Virginia Tech group adds tools to DNA-targeted anti-cancer drugs2
. Virginia Tech football player uses prototype cast3
. Virginia Tech scientists develop process for creating biocompatible fibers4
. Virginia Tech helping to develop higher quality, disease-resistant wheat varieties5
. Virginia Bioinformatics Institutes launches microbial database6
. Virginia Techs System X supercomputer provides super tool for simulation of cell division7
. Weizmann Institute scientists develop a new approach for directing treatment to metastasized prostate cancer in the bones.8
. Affymetrix and the Karolinska Institutet Announce Translational Medicine Strategic Alliance9
. BioMed Central welcomes the new National Institutes of Health public access policy10
. Institute for Systems Biology Symposium Addresses Need for Better Computational Tools11
. UC San Diego partners with Venter Institute to build marine microbial genomics cyberinfrastructure