Ancient creatures re-discovered in southern NZ

Some of the world's most ancient and fascinating creatures have been re-discovered in southern New Zealand.

Over the past two years, Department of Conservation workers and scientists from the National Institute of Water & Atmospheric Research (Niwa) have been searching for phreatoicids.

Phreatoicids are blind, unpigmented isopods (relatives of slaters and fish lice, and a sister group to crabs, shrimps, land hoppers and, more distantly, insects). They play a vital role in cleaning up freshwater.

The search over 230 locations yielded phreatoicids at 66 places, Niwa's assistant regional manager in Christchurch Graham Fenwick said today.

He said phreatoicids had persisted unchanged for some 350 million years but being just 20mm long and dwelling in extremely mucky places, they had lingered mostly forgotten and unnoticed, They were confined to four of ancient Gondwana's five main remnants -- South Africa, India, Australia and New Zealand, but not South America. They were first discovered near Christchurch in 1882 followed by nine more species in 1944.

Niwa's search focused on six species which had not been reported for over 60 years, Dr Fenwick said. Dense populations were found on Ruapuke Island in Foveaux Strait and in Bayswater Peatland Scenic Reserve near Otautau in Southland.

The species lived in surface waters in the southern South Island and appeared to be important in breaking down dead plant matter to recycle their nutrients. The tiny, blind crustaceans played a major role in cleansing the region's groundwater, keeping our drinking water naturally pure, Dr Fenwick said.

"Their high abundances, habitats preferences, and wide tolerances indicate that these ghosts of New Zealand's ancient continental origins can survive in the face of considerable human changes to the landscape, so long as wetlands, in their various forms, are kept intact."