Chelicerates are a group of arthropods that include spiders, scorpions, ticks, and horseshoe crabs. They are characterized by having two main body segments: the cephalothorax and the abdomen. Chelicerates possess specialized mouthparts called chelicerae, which are used for feeding. Unlike other arthropods, chelicerates do not have antennae. Instead, they have simple eyes and often have multiple pairs of legs, typically four pairs. This diverse group plays important roles in ecosystems, such as controlling pest populations and serving as food for other animals.