44 grams (1.55 ounces), about the weight of a golf ball, and an astonishing 40 centimeters (15.75 inches) long, it is an impressively large insect, perfectly adapted to its environment.
The bug's enormous size may be an evolutionary response to its cool, wet mountain habitat, according to Angus Emmott from James Cook University, one of the scientists who helped identify the species.
"Their body mass probably makes them better able to persist in colder conditions," they said, and it probably took millions of years to develop.
The stick insect was discovered high in the canopy of the mountainous Wet Tropics, a remote and mostly inaccessible forest wilderness in northeastern Australia. Its remote existence at high altitude has likely helped keep it concealed to this point, Emmott says.
"Unless a cyclone or a bird brings one down, very few people actually get to see them," he said.
One clue to the identification of this species was given by its unusual eggs, which, in form, surface, texture, and cap design, are unlike the eggs of all other stick-insects. "All species of stick insect have their own particular egg style," Emmott said.
To date, only two specimens of Acrophylla alta are included in the collection of the Queensland Museum, and they will be important resources for further research.
This discovery is not only a rare find and a great contribution to Australia's biodiversity, but also offers great potential for research in insect evolution and adaptation.
