A “giant” trapdoor spider fossil was found in Australia, and all you have to do is take a look at it! Science alert

Even millions of years ago, Australia was a paradise for spiders.

In the heart of the arid continent, scientists have found the exquisitely preserved fossil of a large, striking spider that roamed and hunted in a lush rainforest.

It’s not just a fossilized spider either. It is only the fourth spider fossil ever found in Australia, and the first in the world, of a spider belonging to the large brush-footed trapdoor spider family, Barychelidae. The new species, which lived in the Miocene epoch 11 to 16 million years ago, has been officially named Megamodontium McCloskey.

“Only four spider fossils have been found across the entire continent, which has made it difficult for scientists to understand their evolutionary history. That’s why this discovery is so important, as it reveals new information about the extinction of spiders and fills a gap in the New South Wales and Australian Museum: ‘Understanding the past’.

“The closest living relatives to this fossil now live in the humid forests of Singapore and even Papua New Guinea. This suggests that the group used to live in similar environments on mainland Australia but then became extinct as Australia became drier.”

The spider was discovered among a rich collection of Miocene fossils, which were found in a grassland area in New South Wales known as McGraths Flat.

This assemblage is so exceptional that it has been classified as a Lagerstätte, a sedimentary fossil layer that sometimes preserves soft tissue.

In some excavations from McGrath’s apartment, subcellular structures can be seen.

The type of rock found at the bottom of the fossils makes the whole collection even more fascinating: it’s a type of iron-rich rock called GoethiteIn which exceptional fossils are rarely found. The preservation process was so detailed that researchers were able to recognize minute details in the spider’s body, confidently placing it close to the modern genus. monodontium – But it is five times larger.

That’s not very huge, like monodontium It’s usually quite small, but it’s still the second largest spider fossil ever found, globally. Megamodontium McCloskeyIts body length is 23.31 mm, or just under one inch. With its legs spread, it may fit comfortably in the palm of your hand.

The ancient beast’s massive size makes the detailed preservation of its physical features even more impressive.

“Electron microscopy allowed us to study the fine details of the claws and bristles on the spider’s feet, legs and main body,” explains virologist Michael Freese of the University of Canberra, who scanned the fossils using stacking microscopy.

“Setae are hair-like structures that can have a range of functions. They can sense chemicals and vibrations, defend the spider against attackers and even make sounds.”

The discovery may hold some clues about how Australia has changed over time, as the landscape has dried out dramatically. nothing monodontium or Megamodontium Spiders living in Australia today, suggesting that drought during and after the Miocene was responsible for wiping out some lineages of spiders locally.

We could even learn something about why there are so few trapdoor spiders preserved in the fossil record.

“Not only is it the largest fossilized spider ever found in Australia, it is the first fossil of the family Barychelidae to be found worldwide,” says arachnologist Robert Raven of the Queensland Museum.

“There are about 300 species of trapdoor spiders alive today, but they don’t seem to turn fossils very often. This may be because they spend a lot of time inside burrows, and so are not in the right environment for fossilization.” “.

The research was published in Zoological Journal of the Linnean Society.