"Rebel" CoelacanthRebellatrix, a newfound species of coelacanth, chases down Triassic prey in an illustration.The coelacanth (pronounced SEE-la-kanth) is a primitive, slow-moving fish that's sometimes called a living fossil, because it apparently existed largely unchanged for 320 million years.There are 40 known coelacanth species, 2 of which are alive today. All other known coelacanths have broad, rounded tails designed for slow bursts of motion.But Rebellatrix had a huge, forked tail and streamlined body that likely allowed the ancient fish to cruise long distances and hunt prey at high speeds, said study leader Andrew Wendruff, a biologist at the University of Alberta in Canada.According to Wendruff, the team named the discovery Rebellatrix because, like a true rebel, "it does everything a coelacanth should not do."(Read the full story.)—Christine Dell'Amore

Illustration courtesy Michael Skrepnick