Australian researchers have discovered a huge number of new species of invertebrates, insects and spiders living in underground water, and ‘micro-caverns’ amid the harsh conditions of the Australian outback.
Professor Andy Austin, Director of the Australian Centre for Evolutionary Biology & Biodiversity and colleagues Dr Steve Cooper from the South Australian Museum and Dr Bill Humphreys from the Western Australian Museum, together with other biologists, have just completed a four-year comprehensive survey of underground water, caves and micro-caverns across arid and semi-arid Australia.
The research was sparked off by Dr Humphreys’ discovery in 1994 of tiny underwater invertebrates living in bore water holes on mining and pastoral leases in Western Australia.
The new species were found in bore holes and micro-caverns in the iron rocks of the Pilbara and the Kimberleys that rise like mesas in central Western Australia.
Micro-caverns are tiny crevices up to a centimetre deep in the rocks, which provide a constant temperature and humidity for the microfauna living in them.
Tiny, Blind and Colourless Stygofauna and Troglofauna
The tiny invertebrates are divided into two orders: stygofauna (living in underground water) and troglofauna (living in caves).
Because they are permanently in the dark, they have lost the ability to see, and some have no eyes at all, and all are colourless.
Instead of sight, they rely on vibrations and chemical messages, and have evolved long sensory hairs.
They are also tiny, in order to survive in the micro-caverns of the rocks, with the largest about 10 mm in length and the smallest ones less than a millimetre long.
As well as spiders, the animals most closely resemble centipedes, woodlice, mites and springtails.
Arid Areas of WA were Once Rain Forest
Professor Austin said the 850 new species are not related at all to existing insects, spiders and crustaceans that live in the dry desert conditions and in the underground water holes.
“What we’re seeing here is the result of climate change,” he told Suite101.com. “Thirty million years ago this area was rainforest.”
Giant freshwater crocodiles, huge wombat-like Diprotodons, and flocks of flamingos would have enjoyed the wetlands, and have left fossil remains.
However, insects, spiders and other small invertebrates seldom appear in the fossil record, he said, but biologists could extrapolate from existing rainforest species what the Pleistocene-era invertebrates would have been like.
Professor Austin said DNA matching showed the stygofauna and troglofauna’s relationship to existing Australian rain forest species such as centipedes, mites and springtails.
The Pilbara region began drying out some 15 million years ago, and by four million years ago, it had become desert.
“Over that time, these tiny invertebrates would have moved to find what water they could, and the surface species would have found shelter in micro-caverns,” he said.
"In these isolated favourable habitats, they survived and evolved in isolation from each other."
Microfauna at Risk from Environmental Degradation
Having just been discovered, and with less than half of the 850 new species named, the tiny stygofauna and troglofauna are at risk from environmental damage, Professor Austin warned.
"Discovery of this 'new' biodiversity, although exciting scientifically, also poses a number of challenges for conservation, in that many of these species are found in areas that are potentially impacted by mining and pastoral activities," he said.
Mining particularly poses a threat to the microfauna’s survival. Mining for iron ore is a major industry in Western Australia.
It uses enormous quantities of water each year, drawn from the underground water table via bore holes, originally sunk to allow pastoralists to water their sheep and cattle in semi-arid areas.
As well as water use by the huge iron ore and manganese mines, the underwater invertebrates are threatened by pastoralists on the western side of the Pilbara pumping water for their stock.
Mining also threatens the troglofauna, as crushing the rocks for ore destroys the micro-caverns.
Mining Aids Search for New Species
Professor Austin said that, ironically, mining is proving helpful to conservation biologists, as new mining ventures in Western Australia have to provide comprehensive biological surveys before they are granted mining permission, and this is assisting biologists to discover and document new species.
The 850 new invertebrates were reported on at a scientific conference on evolution and biodiversity in Darwin, Australia, to celebrate the 200th anniversary of Charles Darwin.
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Sue Cartledge - I'm a science, health, nutrition and lifestyle journalist, fascinated by the way the physical world operates in all its forms, and how ...
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