“Astonishing” 500-Million-Year-Old Fossilized Brains Prompt a Rethink of the Evolution of Insects and Spiders July 13, 2022 970 × 546 “Astonishing” 500-Million-Year-Old Fossilized Brains Prompt a Rethink of the Evolution of Insects and Spiders A pair of fossil specimens of Stanleycaris hirpex, specimen ROMIP 65674.1-2.