Diversity “down under”: monogeneans in the Antipodes (Australia) with a prediction of monogenean biodiversity worldwide

Abstract

There are approximately 25 000 species of fishes known in the world. The Monogenea are believed to be among the most host-specific of parasites and if each species of fish is host to a different species of monogenean, there could be almost 25 000 monogenean species on Earth. Currently, I estimate that between 3 000 and 4000 of these are described. Australia 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 3500 species of monogeneans. The first monogenean species described from Australia was Encotyllabe pagrosomi [16]and approximately 300 more species have since been described from the continent. Even in a region of Australia such as Heron Island on the Great Barrier Reef that has been a focus of sustained research on these parasites, only about 85 species are described from 40 of the most common, easily-caught species of fish. Reasons are discussed for the relatively small numbers of monogenean species described so far from Australia. Endemicity is difficult to judge, but only one is certain: Concinnocotyla australensis (Polystomatidae) from Neoceratodus forsteri (Dipnoi). Despite reductions in research funding, the value of parasite taxonomy must not be underestimated, particularly in regions of the world that have a rich diversity of potential hosts.