Living fossil found in Grampians NP
THE DISCOVERY OF a tiny damselfly – which is the only living example of a prehistoric group of species – in two new Victorian locations, has lifted hopes that the insect is moving away from the brink of extinction.
The ancient greenling damselfly (Hemiphlebia mirabilis) measures just 2.4 cm long and was only previously known from nine sites in Victoria, South Australia and Tasmania. Hard to spot, the metallic green species has now been detected in wetlands at Victoria’s Grampians NP, much to the delight of scientists and dragonfly enthusiasts.
“The rarity of the ancient greenling and its small size mean the species is difficult to locate. The adults are only present from late spring to summer, while the aquatic larvae remain hidden in the water for the rest of the year,” says lead researcher behind the finding Dr Di Crowther with Victoria’s Department of Sustainability and Environment (DSE).
Damselfly’s brilliant camouflage makes it difficult to locate
“Not only are the adults brilliantly camouflaged in amongst the reeds of the wetlands they inhabit, they are tiny, with a wingspan of just 22 mm and length of only 24 mm,” she says.
Damselflies are relatives of dragonflies in the order Odonata – while dragonflies have wings that stick out at right angles when they are resting, damselflies can be recognised by wings that lie flat against the body while resting (see image, above).
The ancient greenling is the only living relative of the Hemiphlebiidae family, whose predecessors are found only in 250- to 300-million-year-old fossil records from Brazil to Russia. This makes the species a “living fossil”, says Di, who says that although the find is significant, the ancient greenling isn’t out of the woods just yet.
It is highly sensitive to changes in its environment and was last sighted eight years ago in Yea and Alexandra, in Victoria’s north. Other populations at Wilsons Promontory had been battered by fire and shrinking wetlands, which the species needs to survive. It is not known if the species can fly long distances which would allow it to find new breeding grounds.
Possible unfound damselfly populations
“This find is really significant because that gives hope that maybe there are other populations out there that haven’t been found yet,” Di says. “Hopefully it points to the species being sound. But there are concerns that they are really sensitive to any impact and they will just drop out.”
A genetically diverse population is needed to prevent inbreeding and save the species from extinction, she says: “Every new site found is another step away from extinction.”
The adult ancient greenlings, which are only present from late spring to summer, were discovered at two Grampians wetlands in late 2010 by dragonfly enthusiast and photographer Reiner Richter.
The DSE will continue its research of the species at several of Victorian sites including Yea Wetlands, Wilsons Promontory National Park and the Long Swamp complex in the state’s southwest, as well as the new Grampians sites.