Learn about this "living fossil" fish that was believed to have gone extinct with the dinosaurs. Find articles, images, and RealVideo clips.

Browse photos, species and genus information, and a habitat description of four extinct species of freshwater mussels.

Check out color photos, habitat information, and the story of the comeback of this fish that was considered extinct from 1958 to 1965.

Profile of this sea scorpion includes a physical description, and details on its history and scientific classification.

Describes the Silurian and Devonian period fish that were related to sharks.