Vetulicolia Fossil (image) University of Adelaide Share Print E-Mail Caption A 500-million-year-old fossil used by Australian researchers to make their discovery about vetulicolians. These marine creatures had a rod through their tail similar to a backbone, which places them as distant cousins of vertebrate animals. Credit University of Adelaide/South Australian Museum Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.