The first tardigrades were discovered by Goetz in 1773. Over 400 species have been described since that time. Tardigrades grow only to a size of about 1mm, but they can easily be seen with a microscope. Each limb terminates in four to eight claws or discs. They lumber about in a slow bear-like gait over sand grains or pieces of plant material.
All tardigrades possess a bucco-pharyngeal apparatus, a complex structure.
The claws and the bucco-pharyngeal apparatus are morphological characteristics used to identify the different species. Back to the top Location Tardigrades live in marine, fresh water, and semiaquatic terrestrial environments. If you sample the mosses and lichens in your backyard, your will likely find these tiny creatures. You can find water bears in almost every type of habitat around the world, from moss in a tropical forest to the freezing waters of the Arctic Ocean. They are all, however, considered aquatic to some extent because they must have a film of water surrounding their body to permit gas exchange and prohibit uncontrolled desiccation.