Newly Discovered Widow Spider Lays Bright Purple Eggs

Newly Discovered Widow Spider Lays Bright Purple Eggs
Female Phinda button spider with its purple egg sac. (Photo: Wild Tomorrow Fund)

Scientists have discovered a spider living in South Africa that’s truly a sight to behold. The arachnids feature a scarlet, exclamation mark-shaped blotch on their backs, along with a white squiggle pattern that creates the vague shape of a human face, mouth agape in horror.

Oh, and they lay bright purple eggs.

The South African spiders are “widow” or “button” spiders, and as such are close kin to some of the most notorious spiders on Earth. Latrodectus spiders—like black widows, redback spiders, and katipo spiders—can dispense nasty, dangerously venomous bites to humans. There were already more than 30 of these species known worldwide, but the South African discovery is the first new one in decades.

Barbara Wright, an entomologist at the Wild Tomorrow Fund in South Africa’s Kwa-Zulu Natal Province, and her colleagues first became acquainted with the colourful creature in 2014. They received word from a nearby elephant park that someone had spotted a weird-looking spider living in a tree hollow. Wright rushed over to see it.

“We were shocked and completely blown away by the sheer size [of the spider] and the colours,” recounted Wright in an email to Gizmodo.

Wright and her colleagues watched over the spider for two years, checking in and observing her in her secluded web. When the spider laid a brilliantly purple egg sac, the researchers suspected they might have something weird on their hands.

Eventually, the spider died of old age. Later on, when Ian Englebrecht—an expert on African arachnids—visited one the Fund’s properties, he was shown photos of the spider and “immediately exclaimed ‘oh my God, that’s a new species,’” said Wright.

A male (left) and female (right) Phinda button spider. (Photo: Luke Verburgt)

After much searching in the area, the team found more females of the species (and more of the sickeningly purple egg cases) in a nearby private game reserve. The researchers made careful comparisons between the physical features of the spiders and those of known species and analysed and compared their DNA. Their findings, published recently in the journal Zootaxa, suggest that the spider is a unique species previously unknown to science and possibly to humanity in general.

“We have yet to meet anyone who had seen it before we discovered the first specimen, and that includes local communities,” said Wright. “They are extremely secretive and shy spiders, and hide in tree hollows in a vegetation type that is rare and few people have access to it.”

That rare habitat is a critically endangered ecosystem known as a sand forest, only found in this part of Africa and sporadically in tropical South America. These are surreal places: dense woods plopped on top of ancient sand dunes, now far from the sea.

Sand forest habitat. (Photo: Roger De La Harper)

The new species, dubbed the “Phinda button spider” after the reserve many were found within, has some physical quirks. The females, with their dime-sized bodies, are possibly the heftiest widow spiders yet discovered, for example. But the arachnids’ striking white loops and red blotches are really what inspired their scientific name: Latrodectus umbukwane. “Umbukwane” is an isiZulu word for something so ridiculously eye-catching and beautiful that you can’t just walk past it.

The Phinda button spider probably has a dangerously neurotoxic venom like other widows, but this hasn’t been confirmed, said Wright. Though, given its closer relation to the less-potent “brown widows,” its bite may be relatively weak. Going forward, Wright hopes to investigate the venom in detail.

There’s also some long-term conservation concerns about the species, which seems to only live in pristine patches of sand forest.

“There is not a lot of this vegetation type left in the world,” said Wright, adding that sand forest is very sensitive to human disturbance. “It is extremely slow growing, with some trees being thousands of years old, so they cannot be replaced once destroyed.”

Then there’s the matter of the intensely purple egg sac. No other widow spiders have eggs like this, and it’s unclear why the colour arose or what its purpose might be.

Paula Cushing, an arachnologist at the Denver Museum of Nature & Science who was not involved with the discovery, told Gizmodo by email that the purple colour is odd but not entirely unprecedented. Some ground spiders, she noted, can lay pink or purple egg sacs.

Phinda button spider near a tree hole lair. (Photo: Wild Tomorrow Fund)

For Ingi Agnarsson, an evolutionary biologist at the University of Vermont also not involved with the discovery, the new spider is a testament to how much we still don’t know about Earth’s stupefying diversity of invertebrate life.

“My estimate is that about 70 per cent of spider species are still unknown, so we are really in the age of discovery and exploration when it comes to spider [classification],” Agnarsson told Gizmodo by phone.

These discoveries can apparently still happen in places thought well-covered for spider research, like South Africa.

“It highlights the fact that there is still so much out there, and so many of these species could be lost before we have even discovered or described them,” said Wright.

After all, if we didn’t even notice an “umbukwane” like this spider, what else are we missing?