Strange New Fish Discovered

07 March 2013

A new species of blind cave fish, the Barrow Cave Gudgeon (Milyeringa justitia), has been discovered by a collaborative team of scientists from the South Australian Museum, the Museum & Art Gallery of NT (MAGNT) and the Western Australian Museum.

The South Australian Museum's Ichthyology Collection Manager, Ralph Foster says "based on the genetics, and what we know about the break-up of the ancient 'supercontinents', it seems this population of cave fish has been locked beneath the surface of their little piece of Gondwana for some 80 to 100 million years."

The new species is restricted to the aquifers of Barrow Island, located 50 km off the Pilbara coast in Western Australia. It is just the third subterranean fish species to have been discovered in Australia.

The Barrow Cave Gudgeon specimens were collected from wells and bores sunk in the course of oil exploration.

Genetic studies first alerted South Australian Museum researchers that this was a previously unknown species. DNA analysis revealed it to be a distant relative of a cave gudgeon known from the adjacent mainland.

Surprisingly, related species also occur in Madagascar. They are all blind cave dwellers, indicating that this group had already adapted to a subterranean lifestyle prior to the breakup of the ancient supercontinent of Gondwana, many millions of years ago.

Mr Foster says the new species is "an exciting and important find. "Australia has so few cave fishes, compared to other parts of the world. The evolutionary history and relation to the Madagascan cave gudgeons is fascinating. Certain species of blind cave shrimps from Barrow Island also appear to have relatives in Madagascar."

The MAGNT's Dr Helen Larson, who examined the fish's morphology said "It's a very strange fish. A number of colleagues have remarked how weird it is - and that's coming from a bunch of ichthyologists!

"It lives its entire life underground, lacks pigment and is completely without eyes, finding its way to food with an array of sensory organs on the head and body. The largest specimen known is a mere 23 mm long. We know next to nothing about the species and a lot of work remains to be done."

The Barrow Cave Gudgeon shares its underground world with a rich array of subterranean creatures, known collectively as stygofauna, including a blind cave eel and a wealth of invertebrates under analysis by Dr Bill Humphreys of the Western Australian Museum. Dr Humpheys collected the first Barrow Cave Gudgeon and has documented the high conservation value of the stygofaunal community of Barrow Island. He estimates that no more than 40% of the island's 200 km² overlies potential subterranean habitat for the fish.

Barrow Island has been the site of oil exploration since the 1960s, however development has dramatically surged since the enormous Gorgon Gas Project began. Construction of a Liquefied Natural Gas (LNG) plant that will produce 15 million-tonne per year is underway on the island. A formal assessment of the conservation status of the Barrow Cave Gudgeon has yet to be made but, due to its uniqueness, highly restricted distribution and the potential threats to its habitat, the researchers agree that steps must be implemented to ensure its survival.

The scientific description of the Barrow Cave Gudgeon was published in the journal Zootaxa on 19 February 2013.