Arthropods (jointed foot animals) possess a bilaterally symmetrical, segmented body and appendages, covered by a jointed chitinous exoskeleton, which provides both support and protection for muscles and organs. Living arthropods include: insects, spiders, scorpions, ticks, crabs, lobsters, shrimp, barnacles, ostracods, centipedes and millipedes. Extinct arthropod groups include the eurypterids and trilobites. Arthropods are the most abundant and successful of all animal life forms, having adapted to a large variety of ecological niches by crawling, burrowing, swimming or flying.

 - Trilobites

Vertebrates
 - Mammals
 - Dinosaurs & Birds
 - Reptiles & Amphibians
 - Fishes

Invertebrates
 - Mollusks
 - Echinoderms
 - Arthropods

 - Plants & Amber

 - Minerals
 - Meteorites
 - Geology