Arthropod: Animals with a hard outer coat (exoskeleton) and jointed appendages. Living representatives fall into three groupings. The Crustacea (shrimps, crabs and lobsters). The Chelicerata (spiders, mites and scorpions) and the Uniramia, (insects, and other forms)

     Geological time scale





















Trilobite family numbers through the Phanerozoic

Websites produced by students on the MSc Palaeobiology programme in the Department of Earth Sciences at the University of Bristol for academic year 2003-4