"It's often thought that modern animal groups arose fully formed during the Cambrian Explosion," said Dr Martin Smith of the University's Department of Earth Sciences, the paper's lead author. "But evolution is a gradual process: today's complex anatomies emerged step by step, one feature at a time. By deciphering 'in-between' fossils like Hallucigenia, we can determine how different animal groups built up their modern body plans."
While Hallucigenia had been suspected to be an ancestor of velvet worms, definitive characteristics linking them together had been hard to come by, and their claws had never been studied in detail. Through analysing both the prehistoric and living creatures, the researchers found that claws were the connection joining them together. Cambrian fossils continue to produce new information on origins of complex animals, and the use of high-end imaging techniques and data on living organisms further allows researchers to untangle the enigmatic evolution of earliest creatures.
"An exciting outcome of this study is that it turns our current understanding of the evolutionary tree of arthropods the group including spiders, insects and crustaceans upside down," said Dr Javier Ortega-Hernandez, the paper's co-author. "Most gene-based studies suggest that arthropods and velvet worms are closely related to each other; however, our results indicate that arthropods are actually closer to water bears, or tardigrades, a group of hardy microscopic animals best known for being able to survive the vacuum of space and sub-zero temperatures leaving velvet worms as distant c
|Contact: Craig Brierley|
University of Cambridge