Discovery of new Australian stick insect species reveals case of mistaken identity

While some researchers scan the cosmos for signs of extraterrestrial life, entomologists searching closer to home often find life forms just as striking. In the insect world, nature has already designed creatures that rival science fiction.

That search has now yielded two newly described species in Far North Queensland: Anchiale robusta and Anchiale mabiensis. The findings, detailed in the scientific journal Austral Entomology, highlight just how much remains unknown about Australia’s invertebrate biodiversity.

Anchiale robusta Hiding in Plain Sight Across Queensland

The discovery of Anchiale robusta corrects a decades-long case of mistaken identity. Although the large stick insect has long been popular among insect enthusiasts and scientists, field surveys and genetic analysis revealed that previous taxonomic designations were wrong.

Researchers combined DNA sequencing, museum collections, citizen science records, and targeted field surveys to untangle the history of the genus. In describing two new species and confirming the existence of a third, the research revealed that what were once considered two species are in fact five species in habitats stretching from northern New South Wales into tropical north Queensland.

Females of Anchiale robusta grow to a body length of 120 to 160 millimetres, while males reach 90 to 100mm. Females possess large, mottled wings and inhabit coastal rainforests ranging from Tully to north of Cooktown. According to researchers, female flight is exceedingly rare within the species because they are quite heavy with eggs, though their hindwings often feature striking black coloration with occasional tinges of purple.

Anchiale mabiensis and the Vulnerable Mabi Forest Habitat

In contrast to its coastal relative, Anchiale mabiensis occupies a restricted and fragile range. Discovered on the Atherton Tablelands, this slender species grows to approximately 110 to 120mm and has been observed exclusively within the Mabi Forest.

That restricted geography raises conservation concerns. Terry Carmichael from the Wet Tropics Management Authority noted that while the broader region’s biodiversity is well known and growing, invertebrate tracking lags behind other groups of animal life.

Large portions of the original Mabi Forest have historically been cleared for agricultural development. Because the Mabi rainforest itself is a threatened ecological community under Commonwealth environmental protection legislation, discovering a rare stick insect uniquely adapted to its canopy deepens the conservation value of the remaining ecosystem fragments.

Identification Secrets Held Within Insect Eggs

One of the most unusual aspects of the research involves how the species are identified. While entomologists typically rely on adult morphology, Dr Jones noted that you can take the egg alone and identify the species—a level of consistency he said does not apply to any other organism he knows.

Unlike other stick insect species that glue their eggs down, bury them, or coat them in a silk-like substance, Anchiale mabiensis produces eggs adorned with distinctive rings and a structural lid that detaches when the insect hatches.

These discoveries add to a growing catalog of remarkable Queensland insects. Researchers noted that the Atherton Tablelands also yielded Acrophylla alta, a 40cm-long species discovered recently that weighs slightly less than a golf ball, alongside Australia’s longest stick insect species, which can exceed half a metre in length.