An international team of scientists has unveiled a remarkable update to the classification of Australia’s most infamous spider—the Sydney funnel-web. Known for its deadly bite, the Sydney funnel-web spider has long been considered a single species. However, new research suggests that spiders in the Sydney region represent not one, but three distinct species. This groundbreaking discovery offers new insights into the biology and behavior of one of the world’s most feared arachnids.
The study, published in the journal BMC Ecology and Evolution, was the result of collaboration between scientists from the Leibniz Institute for the Analysis of Biodiversity Change (LIB) in Germany, the Australian Museum (AM) in Sydney, and Flinders University in Adelaide. By examining both anatomical features and molecular DNA, the team was able to identify differences that had long been overlooked, shedding light on the true diversity of Sydney’s funnel-web spiders.
The Three Species of Sydney Funnel-Web Spiders
Previously, the Sydney funnel-web spider (scientific name Atrax robustus) was thought to be a single species, found across the Sydney Basin. But this new research paints a more complex picture, revealing that funnel-web spiders in the Sydney region belong to three distinct species, each with its own unique characteristics.
- The Classic Sydney Funnel-Web (Atrax robustus)
This is the “true” Sydney funnel-web, which has long been associated with the city. Found predominantly in the northern suburbs of Sydney, the Central Coast, and as far west as Baulkham Hills, this species remains the most recognized and feared. The Atrax robustus is still considered the most dangerous in terms of venom potency, though modern antivenoms have dramatically reduced fatalities. - The Southern Sydney Funnel-Web (Atrax montanus)
Resurrected as a species name dating back to 1914, the Atrax montanus is found primarily in the Blue Mountains, to the south and west of Sydney. Though less well-known, this species is equally venomous and important to understanding the broader funnel-web family. - The Newcastle Funnel-Web (Atrax christenseni)
Perhaps the most exciting discovery was the identification of a completely new species: Atrax christenseni, commonly known as the “Newcastle funnel-web” or affectionately “Big Boy” by spider enthusiasts. This species, which is the largest of the three, is found exclusively in the Newcastle region, around 150 kilometers north of Sydney. Not only is this species larger than its relatives, but its distinct genetic and anatomical features warranted its classification as a separate species.
The Role of DNA and Morphological Comparisons
The study’s findings are the result of extensive molecular (DNA) comparisons, as well as detailed anatomical analysis. These methods allowed the researchers to differentiate between subtle but important variations in the spiders’ features, such as their size, venom composition, and even their mating behaviors.
Lead researcher Dr. Stephanie Loria of the Leibniz Institute for the Analysis of Biodiversity Change explained, “Our research uncovered hidden diversity among funnel-web spiders. The Newcastle funnel-web, Atrax christenseni, is a totally new species. The ‘true’ Sydney funnel-web, Atrax robustus, centers on the North Shore of Sydney and the Central Coast, and the Southern Sydney funnel-web, Atrax montanus, is a resurrected species name from 1914.”
The work of the research team also relied on the Australian Museum’s extensive historical collections, some specimens of which date back to the early 1900s. This unique collection helped illuminate the evolutionary and ecological histories of the various funnel-web species.
The Discovery’s Implications for Antivenom and Venom Research
One of the more practical implications of this discovery could be for the development and optimization of antivenoms. Since 1981, the Australian Reptile Park has operated a Venom Milking Program, collecting venom from funnel-web spiders for antivenom production. Despite the fact that no fatalities from funnel-web bites have been reported since the development of antivenom in the 1980s, understanding the biological differences between the newly recognized species could lead to more effective treatments.
Dr. Danilo Harms, co-lead author of the paper, noted, “Although no human fatalities have occurred since the development of antivenom, the antivenom for Sydney funnel-web spiders might be optimized by considering biological differentiation at the species level.” However, he also reassured the public that the current antivenom remains effective against all three species of Sydney funnel-webs, as well as other closely related species that can cause serious envenomations in eastern Australia.
Dr. Helen Smith, an arachnologist at the Australian Museum, emphasized that understanding this species’ diversity could lead to more refined treatments for funnel-web bites in the future, improving safety and outcomes for individuals who are bitten.
Funnel-Web Envenomations and Public Safety
Despite their fearsome reputation, funnel-web bites remain rare. Most envenomations occur when male funnel-web spiders leave their burrows during the mating season in search of females. These wandering males are more likely to bite when they feel threatened or cornered.
Professor Geoff Isbister, Director of the Department of Clinical Toxicology at Calvary Mater Newcastle, explained, “Funnel-web bites are the most severe among spiders, but they are not very common. If you are bitten by a funnel-web spider, call an ambulance and go straight to hospital.” The availability of antivenom and the advancement in medical treatment has made fatalities extremely rare.
Spiders: Ancient Creatures with Remarkable Adaptations
Spiders, as a group, have existed for over 300 million years—long before dinosaurs roamed the Earth. These fascinating creatures have mastered nearly every ecosystem on the planet and play vital roles in controlling insect populations and maintaining ecological balance.
Professor Kris Helgen, Chief Scientist and Director of the Australian Museum Research Institute, highlighted the impressive adaptability and diversity of spiders: “Spiders are older than the dinosaurs. They are astonishingly diverse—there are about 52,500 known living spider species, and potentially many more to discover.”
The Australian Museum houses one of the world’s largest and most valuable spider collections, with hundreds of thousands of specimens. Among these are about 4,000 funnel-web spiders, including the original male Sydney funnel-web that was responsible for the first recorded human fatality from a funnel-web bite. This collection has been invaluable to researchers and will continue to play a critical role in the ongoing study of arachnid diversity.
The Naming of Atrax christenseni
As part of this study, the newly identified species of funnel-web from Newcastle was given the name Atrax christenseni in honor of Kane Christensen, a passionate spider enthusiast who played a crucial role in bringing the large funnel-web males from Newcastle to the attention of researchers. Christensen had been involved in the Australian Reptile Park’s Venom Program and contributed significantly to the identification of this new species.
Dr. Helen Smith explained, “Kane has been instrumental in the identification of this new species, collecting specimens so that we could do further analysis. To show how much Kane’s work meant to us, we have called it Atrax christenseni. We named it after him.” Christensen expressed his gratitude and excitement at the honor, noting that the size of the male Newcastle funnel-web spiders was “simply astounding” compared to their southern counterparts.
“I am deeply honored and accept it with great pleasure,” said Christensen. “It has been a privilege and a joy to help shine a light on one of Australia’s formidable species, our feared and revered funnel-web.”
Conclusion: A Step Forward in Understanding Australia’s Funnel-Web Spiders
This research has not only redefined the classification of the Sydney funnel-web spider but has also opened up new avenues for understanding the evolution, ecology, and venom biology of these fascinating arachnids. The study emphasizes the importance of using both modern and historical data, as well as international collaboration, in advancing scientific knowledge.
The discovery of Atrax christenseni and the clearer understanding of the Sydney funnel-web’s diversity mark a significant milestone in the study of arachnids. It also reinforces the role of museums and collections in supporting cutting-edge research that can lead to practical applications, such as improved antivenom and better public health measures.
As scientists continue to study these enigmatic creatures, one thing is certain: the Sydney funnel-web, in all its new and mysterious forms, remains a symbol of Australia’s rich and diverse natural heritage.
Reference: Stephanie F. Loria et al, The world’s most venomous spider is a species complex: systematics of the Sydney funnel-web spider (Atracidae: Atrax robustus), BMC Ecology and Evolution (2025). DOI: 10.1186/s12862-024-02332-0