video: A group of researchers led by geobiologist Dr. Ernesto Pecoits of the University of Alberta have found the oldest evidence of bilaterian animals yet reported. This finding was made in the northeast part of Uruguay, where bilaterian burrows are preserved in fine detail in shallow-water glaciomarine sediments of the Tacuarí Formation. Cross-cutting granite dykes constrain the minimum age of these burrows at 585 million years old, extending the fossil record of bilaterians at least 30 million years backward, a time coincident with previous molecular clock studies. Therefore, this discovery not only unites the paleontological and molecular data with respect to the evolution of bilaterians but also it links their origin to the severe environmental changes that took place during the Neoproterozoic. This video relates to a paper that appeared in the June 29, 2012, issue of Science, published by AAAS. The paper, by Ernesto Pecoits at the University of Alberta in Edmonton, AB, Canada, and colleagues was titled, "Bilaterian Burrows and Grazing Behavior at >585 Million Years Ago." view more
Credit: [Video courtesy of Ernesto Pecoits and Natalie Aubet]