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 more than one hundred species between them: "Euastacus", around the Australian coast from Melbourne to Brisbane, and "Cherax" across Australia and New Guinea.