Spiders, crabs, and other arthropods evolved from a group of animals that underwent a burst of diversity around 500 million ...

They’re also one of the world’s largest arthropods, animals with no backbone, external skeletons, and multiple-jointed appendages. In this crab’s case, those appendages are its 10 legs.

A never-before-seen predatory crustacean that feeds on other smaller creatures in the hadal zone was discovered in the ...

The horseshoe crab’s carapace hides 12 appendages. One pair, called the chelicerae, is used to push food, such as small invertebrates or algae, into its mouth. The other five pairs are used for ...

A Pacific mole crab, or a sandcrab, in an aquarium. You can see the feeding appendages are out feeling for food in the water. PSU researcher Dorothy Horn examined the effects of exposure to ...