New populations of the rare subterranean blind cave eel Ophisternon candidum (Synbranchidae) reveal recent historical connections throughout north-western Australia

Abstract

The enigmatic blind cave eel Ophisternon candidum is one of Australia’s least known fishes and is one of only three vertebrates in Australia with an entirely subterranean existence. For more than half a century, O. candidum was thought to be restricted to some 100km of coastal cave systems in north-western Australia. Herein we report on two new populations, each separated by hundreds of kilometres, and provide the first complete list of all known records of subterranean Ophisternon in Western Australia. Using morphological and molecular data, we show that these populations are conspecific, with one population showing evidence of genetic differentiation. Geological and biogeographic explanations are explored, along with conservation considerations. All populations face actual and potential threats, especially from mining activities, and there is a need for management and conservation strategies specific to each population.