Three-feet-long might not seem like that much, but consider the size of other marine animals then. We're talking about some of the world's first animals, after about 100 million years or so of evolution. The oceans included, as they do today, unicellular microscopic organisms as well as creatures like the 1.5-foot-long Hurdia.
(Hurdia, Credit: Marianne Collins)
Supporting evidence of the predator's dominance includes damage to contemporaneous trilobites, and even its fossilised poo (or coprolites) containing the remains of its prey.
The eyesight of Anomalocaris, now understood thanks to the recent fossil discovery, proves that this marine dweller had superb vision to support its predator lifestyle near what is now Kangaroo Island. The site dates to 515 million years ago, so it's possible the bug-eyed hunter goes back even earlier in time.
The fossils represent compound eyes. These are the multi-faceted kind seen in arthropods, such as flies, crabs and kin. They are perhaps the largest of their kind to have ever existed, with each eye over 1 inch in length and containing over 16,000 lenses.