Never-before-seen head of prehistoric, car-size 'millipede' solves evolutionary mystery
But with the discovery of an intact head, "the mystery of Anthropleura now appears solved." Related: 7-foot-long arthropods commanded the sea 470 million years ago, 'exquisite' fossils show The CT scans virtually uncovered the fossilized head of two juvenile Arthropleura discovered within rock in the Montceau-les-Mines Lagerstätte fossil site in France.