A ‘mega’ spider five times larger than normal arachnids has been discovered in Australia (but luckily it went extinct 11 million years ago)

Scientists have found that millions of years ago, a terrifying trapdoor spider measuring more than 20 mm long roamed the region of Australia.

The spider, named Megamonodontium mccluskyi, was unearthed by a group of scientists working at a renowned fossil site in the Central Tablelands of New South Wales.

At 23 mm long, the spider fossil is the second largest fossil ever discovered and more than five times larger than its modern-day relatives.

The fossilized arachnid resembles brush-footed trapdoor spiders in western New South Wales and marks a major discovery for researchers.

UNSW paleontologist Matthew McCurry said only four spider fossils had been found in Australia, making it difficult to understand their history.

The spider, named Megamonodontium mccluskyi, was unearthed by a group of scientists in central New South Wales. Image: Supplied/Australia Museum

The fossilized arachnid resembles a species of rush-footed trapdoor spider found in western New South Wales. Image: Supplied/Australia Museum

“This discovery is so significant that it reveals new information about the extinction of spiders and fills a gap in our understanding,” he said.

“The closest living relative of this fossil now lives in wet forests from Singapore to Papua New Guinea.”

“This suggests the group once inhabited similar areas on mainland Australia but became extinct as Australia became increasingly arid.”

The fossil is between 11 and 16 million years old and takes its name from the man who unearthed it: Dr. Simon McClusky.

His discovery was the culmination of work by scientists from ANU, UC and UNSW, the results of which have since been published.

UNSW paleontologist Dr. Matthew McCurry said only four spider fossils had been found in Australia. Image: Supplied/Australian Museum/Salty Dingo

Queensland Museum arachnologist Robert Raven and the supervising author said the fossil was the largest spider fossil ever found in Australia.

“(The spider) is the first fossil of the Barychelidae family found anywhere in the world,” said Dr. Raven.

“There are about 300 species of brush-footed trapdoor spiders alive today, but they don’t seem to become fossils very often.”

“This could be because they spend so much time in caves and are therefore not in the right environment to become fossilized.”

The fossil is now in the Australian Museum’s paleontology collection and is available for researchers to study online.

The site where it was excavated, McGraths Flat near Gulgong, was also recently discovered to be home to a new fossilized jumping spider.