Metaspriggina is an early chordate, dated at 505 million years ago. Specimen fossils have been discovered by Jean-Bernard Caron at Marble Canyon, in the Canadian Rockies. They were identified by Simon Conway Morris, as a type of fish which he had first discovered in 1978. The specimens are two inches long, without jaws, but with a cartilage notochord. The specimen possesses two upward-looking eyes, gills, liver, and W-shaped muscles along the entire length of the body, similar in function to the muscles of today's fish.