The animal that once lived in the ancient sea looks like a bird's nest in fossil form.
The specimen, approximately 560 million years old, contains fibrous bundles that appear to be muscle tissue, an important evolutionary adaptation.
Some scientists are arguing that humans today are wiping out animal species at a rate that matches up with past mass die-offs. Is the end nigh? Laci Green has the details.
One of the first predators of its day, the creature sported compound eyes, body armor and two spiky claws for grabbing prey.
A fossilized brain in the preserved remains of an extinct arthropod reveals an ancient nervous system remarkably similar to that of modern-day spiders and scorpions.