From 520 million years ago, in China Cambrian shale, an arthropod with current extant relatives with similar brains. How did such neural complexity appear out of nowhere? The Pre-cambrian fossils are all simple soft-bodied organisms in a sandstone like rock. The Cambrian has been a wooden stake in the heart of Darwinism since Charles, himself, discussed the problems it presented. This is the most complex Cambrian brain found so far.-http://phys.org/news/2012-10-complex-brains-evolved-earlier-previously.html