DIVERSITY DOWN-UNDER - MONOGENEANS IN THE ANTIPODES (AUSTRALIA) WITH A PREDICTION OF MONOGENEAN BIODIVERSITY WORLDWIDE

There are approximately 25000 species of fishes known in the world. Th e Monogenea are believed to be among the most host-specific of parasit es and if each species of fish is host to a different species of monog enean, there could be almost 25000 monogenean species on Earth. Curren tly, I estimate that between 3000 and 4000 of these are described. Aus tralia has a rich marine fish fauna with approximately 3500 species of teleosts. If the same formula of one monogenean species per host fish species is applied, Australian marine fishes could host potentially 3 500 species of monogeneans. The first monogenean species described fro m Australia was Encotyllabe pagrosomi MacCallum, 1917 and approximatel y 300 more species have since been described from the continent. Even in a region of Australia such as Her-on Island on the Great Barrier Re ef that has been a focus of sustained research on these parasites, onl y about 85 species are described from 40 of the most common, easily-ca ught species of fish. Reasons are discussed for the relatively small n umbers of monogenean species described so far from Australia. Endemici ty is difficult to judge, but only one is certain: Concinnocotyla,ln a ustralensis (Polystomatidae) from Neoceratodus forsteri (Dipnoi). Desp ite reductions in research funding, the value of parasite taxonomy mus t not be underestimated, particularly in regions of the world that hav e a rich diversity of potential hosts. (C) 1998 Australian Society for Parasitology. Published by Elsevier Science Ltd. All rights reserved.