Today's Mising Link Found: Whales with Baleen and Teeth

Modern whales fall into two groups, those with teeth and those with baleen. Since early whales all had teeth, baleen must have evolved after whales took to the water. And now there is excellent fossil evidence of the transition, numerous species of whales with primitive baleen. Paleontologists in California have just announced the discovery of four new species of whales with both teeth and primitive baleen, dating to between 17 and 19 million years ago. Above, a jaw fragment from one of the whales.