Overview
Parastacidae is the family of freshwater crayfish found in the southern hemisphere. The family is a classic Gondwana-distributed taxon, with extant members in South America, Madagascar, Australia, New Zealand and New Guinea, and extinct taxa also in Antarctica.
Three genera are found in Chile, Virilastacus, Samastacus and Parastacus, the last of which also occurs disjunctly in southern Brazil.
There are no crayfish native to continental Africa, but six species on Madagasc ar, all of the genus Astacoides.[3]
Australasia is particularly rich in crayfish. The small genus Paranephrops is endemic to New Zealand. Two genera, Astacopsis and Parastacoides are endemic to Tasmania, while a further two are found on either side of the Bass Strait ? Geocharax and Engaeus. The greatest diversity, however, is found on the Australian mainland. Three genera are endemic and have restricted distributions (Engaewa, Gramastacus and Tenuibranchiurus), while two are more widespread and contain nearly ninety species between them: Euastacus, around the Australian coast from Melbourne to Brisbane, and Cherax across Australia and New Guinea.species,
Fossil record
The oldest specimens from the family Parastacidae are the Albian fossils of Palaeoechinastacus from Victoria, A ustralia.[4] The only northern hemisphere representative is also a fossil, Aenigmastacus crandalli from Canada.[5]
80huxl.