Where do yabbies come from originally?
Australia and southern PNG have a rich freshwater crayfish fauna of over a 100 different species and there are a few similar species in NZ, South America and Madagascar. These are a different family (the Parastacidae) from freshwater crayfish in the northern hemisphere (the Astacidae in Europe and the Cambaridae in North America and eastern Asia). All these crayfish evolved from ancient prototype marine lobsters. This move to freshwater happened separately in the two hemispheres of the earth more than a hundred million years ago when Australia, India, Africa and Australia-NZ were together, attached to Antarctica as the giant southern continent called Gwondanaland. India and Africa broke off first to drift north before freshwater crayfish could spread from the original freshwater site (SE Australia) which was invaded from the sea, so none are found in these countries. A few crayfish spread to South America, NZ and Madagascar before these countries split off and drifted north. As Austral
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