The Sydney funnel-web spider, a highly venomous arachnid found crawling in and around Australia’s most populous city, was long thought to be a single species. But it’s actually three different species, a new study has found. One of these, called “Big Boy” for its unusually large size, is new to science.
“You would think we would’ve had the Sydney funnel-web spider’s diversity and evolution figured out because it’s such a charismatic animal, but it just goes to show that for most of arthropods, we know so little,” study lead author Stephanie Loria, formerly a researcher at the Museum of Nature in Hamburg, Germany, told Mongabay by phone.
The dark, glossy Sydney funnel-web spider was originally described in 1877 as Atrax robustus. The name stuck until more recently when staff at the Australian Reptile Park, which milks venom from the fangs of Sydney funnel-webs to produce antivenom, reported noticing some unusually large individuals originating from around the neighboring city of Newcastle.
Intrigued, researchers collected funnel-web spiders from the Sydney region and compared them with specimens held in the Australian Museum.
Genetic analysis split the spiders into three very distinct groups. When dissected and studied under a microscope, the three groups also looked different, with very different genitalia.
The study now identifies three species of Sydney funnel-web spider:
The classic Sydney funnel-web spider (Atrax robustus) is found mainly in the greater Sydney region and Central Coast.
The Southern Sydney funnel-web (Atrax montanus) occurs mostly south and west of Sydney, with some overlap in its distribution with A. robustus. In 1914, it was described as a separate species but was later reclassified as a Sydney funnel-web. “We revalidated that old hypothesis,” Loria said.
The Newcastle funnel-web (Atrax christenseni), whose males are the largest of the three species, is found only in a small area surrounding Newcastle. Also dubbed “Big Boy,” the Newcastle funnel-web is new to science and is named after Kane Christensen, a former employee at the Australian Reptile Park who brought the spiders to the researchers’ attention.
The conservation status of the Sydney funnel-web hasn’t been assessed on the IUCN Red List. However, the split into three species means “you have more species with smaller ranges rather than just one thing that’s quite common,” Loria said. “So, there’s more potential threats.”
At least 13 human deaths have been linked to Sydney funnel-web bites, particularly by males. However, no deaths have been recorded since antivenom was introduced in 1981.
Geoff Isbister, a clinical toxicologist at the University of Newcastle, who wasn’t involved in the study, told ABC News it’s unknown whether the potency of venom differs among the three newly differentiated species.
While the current antivenom seems to be effective across all the species, the new research can be used to optimize antivenom by considering species-level differences, study co-author Danilo Harms, from the Museum of Nature, said in a statement.
Banner image of Newcastle funnel-web spider, courtesy of Kane Christensen.
