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Kane Christensen’s passion is an arachnophobe’s nightmare. For two decades, he worked with deadly spiders at the Australian Reptile Park, a zoo located 80km north of Sydney – paying such close attention to the eight-legged predators that he helped scientists discover two new species.
He began there as a volunteer in 2003, milking venom from the fangs of Sydney funnel-web spiders. The park takes donations of captured male spiders from the public, using their venom to create life-saving antivenom. “Funnel-webs for me are just the pinnacle,” Christensen says.
Australian funnel-web spiders are a family of glossy, dark arachnids. Several species contain venom that can cause serious damage to humans; though it isn’t the most venomous species, the Sydney funnel-web is thought to be responsible for the most deaths, with at least 13 recorded victims.
Almost immediately, Christensen began noticing that some of the Sydney funnel-webs being brought to the park – particularly those originating from farther north, around the coastal city of Newcastle – were much larger than others, with distinct differences in the appearance of their genital bulbs.
Intrigued, Christensen reached out to scientists at the Australian Museum. His hunch turned out to be correct: the “big boys” from Newcastle weren’t Sydney funnel-webs, Atrax robustus, but a new species entirely. This week, in a dream outcome for the self-professed spider-lover, the Newcastle funnel-web was officially named after Christensen: Atrax christenseni.
Last week, the Australian Reptile Park announced the largest male funnel-web it has ever found. Male funnel-webs typically range from 1cm to 5cm in size (females are larger, but not as venomous); dubbed Hemsworth after the actor brothers, this record-breaking spider captured near Newcastle had a legspan of 9.2cm.
On Tuesday, Hemsworth was officially confirmed as belonging to the new species, the Newcastle funnel-web, after an assessment by Christensen and experts at the Australian Museum.
It took years to examine and run DNA analyses on spider specimens from across Australia’s south-east, with hold-ups as a result of the Covid-19 pandemic. In the process of reclassifying the “big boys” from Newcastle, scientists also discovered a third distinct species.
Named the southern Sydney funnel-web, Atrax montanus, the third species was found to overlap in distribution with the true Sydney funnel-web. Atrax montanus had originally been described as a separate species in 1914, a classification that was later nullified.
“Even though they were almost identical morphologically, what was originally described with this other name is a different species,” says Dr Bruno Alves Buzatto of Flinders University, a co-author of the paper reclassifying the spiders.
The discovery brings the total number of known Australian funnel-web species to 38.
The Newcastle funnel-web is “a very distinctive spider in terms of its evolutionary history”, says Prof Kris Helgen, director of the Australian Museum Research Institute. It last shared a common ancestor with the Sydney funnel-web spider 17m years ago.
The first “true” Sydney funnel-web specimen is a female spider housed at the Natural History Museum in London.
The Newcastle “big boy” has thicker legs than the Sydney funnel-web, but the easiest way of telling them apart is via their reproductive organs.
The spiders “don’t have a penis to directly transfer sperm from the male to the female,” Buzatto says. “They use these things that we call copulatory bulbs,” which are located on the spiders’ pedipalps – miniature leg-like appendages at the front of their face.
Buzatto likens the copulatory bulbs to very long syringes which transfer sperm to the female, in a lock-and-key-like mechanism.
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The copulatory organ on the Newcastle funnel-web “looks totally different to everything else,” Christensen says. “It’s crazy, it is so big … If it tried to mate with a Sydney funnel-web female, it would pierce straight through her, basically.”
“We know that the Newcastle species is a much rarer species,” says Buzatto. The spider is found in only a few sites; the researchers are keeping their exact locations a secret out of conservation concerns. The removal of these funnel-webs from their natural habitat could have significant impacts on their population, Buzatto says.
Funnel-webs are old world spiders, which create burrows with a funnel-shaped “web sock”, says Dr David Wilson, a venom expert at James Cook University. The web sock has trip lines that extend out of the burrow, which are triggered by unsuspecting passing prey.
What makes Sydney funnel-web venom so deadly is a group of peptides called delta-atracotoxins, which can cause muscle fasciculations, respiratory and circulatory failure in humans. “The peptides are quite active against insects but coincidentally happen to knock primates around in a big way,” Wilson says.
Female Sydney funnel-webs are not nearly as dangerous because the delta toxin family isn’t found in their venom. “It comes into the male venom after they go through their maturing moult … somewhere around five to seven years [old],” Wilson says.
The Newcastle “big boy” carries the same delta toxins that the Sydney funnel-web does, Wilson says. “Based on their size, they’re likely to be able to deliver more venom. The bigger the spider, the bigger the venom glands.” He is keen to analyse the new species for any specific venom differences.
The new species is not the most dangerous of the funnel-webs: that dubious honour may belong to the northern tree-dwelling funnel-web, whose venom is likely more toxic, Wilson says. Found farther north, in New South Wales but also the north-eastern state of Queensland, “they’re generally not encountered very often,” he says.
Nobody has died in Australia from a funnel-web bite since the introduction of antivenom in 1981, which is effective against a number of different species. Antivenom is also thought to be effective against the two new species, Helgen says.
Christensen received a call a few years ago from Buzatto informing him of the impending spider naming. It “absolutely floored me”, he says.
“That was just an honour I can’t describe – I’m trying to still find the words for it.”
