Early Cambrian arthropod chain gangs this learn node describes are fossilized in chain formation that reveals community behavior. The chain gang 525-million-year-old fossils were found in southern China’s Chengjiang Lagerstatte fossil field. A Science News report of the discovery says that the discovery site is “a treasure trove of fossils often compared to Canada’s Burgess Shale.” The above image from Science News (credit Derek Siviter) shows the that newly discovered species of Early Cambrian arthropod formed sturdy chains of about 20 individuals. In the report:
Nigel Hughes, a paleobiologist from the University of California, Riverside comments that these types of finds provide snapshot scenes of “normal” life.
“Of the millions of fossils, the chances of getting an occurrence where we can determine collective behavior is quite rare,” says coauthor Derek Siveter of the University of Oxford in England. He and his colleagues found 22 complete or partial chains, but only one solitary specimen.
A Brief History of Life on Earth provided at Connexions sets the time frame for these fossils
Called “Showdown on the Burgess Shale,” two lectures in 
