Two New Australian Stick Insect Species Identified, One Long Misidentified
Two large stick insect species found in far north Queensland are new to science, one of them misidentified for decades, researchers say.
The two species are described in the study, reported by the Guardian, which combined DNA analysis with museum collections, citizen science records and field surveys. The first, Anchiale robusta, has long been popular among insect enthusiasts and known to scientists, but the new analysis found that its previous designation was a case of mistaken identity.
"When we went out into the field, and we saw a whole bunch of different individuals that looked morphologically different, and they were also living in ... different habitats, that was our first hint that there was a bit more of a complicated story here," said the study's lead author, Dr Braxton Jones of the University of Sydney.
Anchiale robusta females grow to a body length of 12 to 16 centimetres, while males reach 9 to 10 centimetres. "Mostly their wings are black but some of them have a little bit of purple on the underside of their hindwing," Jones said. He added that males are always smaller than females, and that it is "incredibly rare" for a female to be able to fly because they are heavy with eggs.
The second species, Anchiale mabiensis, lives in the critically endangered Mabi rainforest of Queensland's Atherton tablelands. Its females are about 11 to 12 centimetres long, and its eggs have an unusual structural "lid" that detaches when the insects hatch, Jones said.
In describing two new species and confirming the existence of a third, the research found that what were once considered two species are in fact five, living in habitats stretching from northern New South Wales into tropical north Queensland. Jones said that finding had important conservation implications, because the species occupy smaller habitat ranges than previously thought.
Jones said animals of the Anchiale genus are among the most documented stick insects on citizen science platforms, because there are quite a lot of them and they can hatch in large numbers. Even so, he said, "there's so much we don't know about them".
The study also identified another probable new species in Cape York, but more specimens are needed to confirm it.
Other large stick insects have recently been recorded in the same region. Last year, also on the Atherton tablelands, scientists discovered a 40-centimetre-long species, Acrophylla alta, which weighs slightly less than a golf ball and which they noted could be the heaviest insect in Australia. Australia's longest species, the gargantuan stick insect, is also found in northeastern Queensland, and its females can grow to more than half a metre in length.