Onychoporans share certain characters with arthropods, but are lacking a hard exoskeleton or jointed legs. Onychophorans are probably closely related to arthropods and branched off the tree just before a fully hardened exoskeleton and jointed legs evolved.

Although not officially part of our arthropod story, they certainly deserve a closer look. These candy-colored animals can be bright blue, purple, orange, and green, and are covered in warty bumps. These carnivorous rain-forest dwellers have an unusual hunting style. They pursue small snails, worms, and insects and then shoot a glue-like substance at the intended victim, which quickly hardens and traps the prey.