Exquisitely detailed 520 million-year-old fossil shows individual nerves
Scientists have seen animals of similar age with preserved ganglia before [...] But Chengjiangocaris kunmingensis also shows a few dozen delicate, tiny individual nerve fibers sprouting out from the nerve cord and ganglia. [...] "By contrast, arthropods of today only have the ganglia, but a very restricted number of the lateral nerves," he said. "The only living group today where scientists have found dozens of individual nerve fibers structured like these are priapulids (penis worms) and onychophorans (velvet worms), which are cousins of arthropods.