Scientists have discovered that a hideous trapdoor spider measuring more than 20mm long roamed regional Australia millions of years ago.
The spider, called Megamonodontium mccluskyi, was unearthed by a group of scientists working at a renowned fossil site in the Central Tablelands of New South Wales.
At 23mm in length, the spider fossil is the second largest ever discovered and is more than five times the size of its extant relatives.
The fossilized arachnid resembles the brush-footed trapdoor spiders of western New South Wales and is an important discovery for researchers.
UNSW palaeontologist Matthew McCurry said only four spider fossils had been found in Australia, making it difficult to understand their history.
The spider, called Megamonodontium mccluskyi, was unearthed by a group of scientists in central New South Wales. Image: Supplied/Australian Museum

The fossilized arachnid resembles species of reed-legged trapdoor spiders from western New South Wales. Image: Supplied/Australian Museum
“This discovery is so significant that it reveals new information about spider extinction and fills a gap in our understanding,” he said.
“The closest living relative of this fossil currently lives in rainforests from Singapore to Papua New Guinea.
“This suggests that the group once occupied similar environments on mainland Australia, but became extinct as Australia became more arid.”
The fossil is between 11 and 16 million years old and is named after the man who unearthed it, Dr. Simon McClusky.
Its discovery was the culmination of work by scientists from ANU, UC and UNSW whose findings have since been published.

UNSW palaeontologist Dr Matthew McCurry said only four spider fossils have been found in Australia. Image: Supplied / Australian Museum / Salty Dingo
Queensland Museum arachnologist Robert Raven, supervising author, said the fossil was the largest fossil spider ever found in Australia.
“(The spider) is the first fossil of the Barychelidae family to have been found anywhere in the world,” Dr Raven said.
“There are around 300 species of brush-legged trapdoor spiders today, but they don’t seem to become fossils very often.
“This could be because they spend a lot of time inside burrows and are therefore not in the right environment to fossilize.”
The fossil is now in the Australian Museum’s palaeontology collection and is available online for researchers to study.
The site where it was unearthed, McGraths Flat, near Gulgong, was also recently discovered to be home to a new fossilized jumping spider.