Female (left) and male (right) South-eastern Petaltail
This giant dragonfly from the family Petaluridae is the third largest in Australia and one of the largest in the world. About 190 million years ago in the Jurassic, enormous dragonflies of this family lived in swamps and bogs. Today, there are 10 surviving species almost unchanged in form and habit. Five of these live in Australia, including this species.
Giant dragonfly larvae hatch out of eggs laid around swamps and dig long burrows. They are semi-terrestrial, unlike other dragonflies, and roam the surface of the swamp at night or in wet weather in search of insects and other arthropods to eat. This larval stage may last over 10 years, whereas the adult stage only lasts one summer. Adults are surprisingly poor flyers and don’t range far from their swamp.
The combination of poor dispersal ability, long larval life and the need for a permanent swamp makes the Petaltail very susceptible to human interference. Habitat loss and modification are a major problem and include draining, long-wall mining, flooding and polluted run-off for the larvae. Petalura gigantea was recorded from the marshes around Sydney and Cronulla early last century but is not found there today.
The management plan for this species includes searching for more populations and researching the life cycle and effects of threatening processes. Meanwhile, remaining habitats are being protected.
Distribution: South-west Rocks to southern Highlands in New South Wales
Conservation status: not IUCN assessed, but listed as ‘Endangered’ in NSW
Evolutionary distinctiveness: not assessed