| Isopods
are curious creatures. They are crustaceans (as are crabs
and shrimps and crayfish) and most live in water. Some
however, live on land under leaves or logs, and others, like
the one illustrated, live partially in both. A problem that
an aquatic animal has when living on land is breathing air.
Most crustaceans have gills over which water flows to extract
oxygen. Land-dwelling isopods, however, have feathery 'false
lungs' on two of their hind limbs as a primitive method of
breathing.
The prehistoric-looking creature in
the picture has no common name as very few people even know it
exists. Yet it has been around for a very long time.
Fossil studies in Australia have found animals which look
virtually identical to Phreatoicopsis (pronounced free-atoe-ee-cop-sis)
from 325 million years ago. These little creatures, which
are about 2-3 cm long, are as close as we get to true living
fossils.
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