There have been very few fossil spiders found in Australia. Only four spider fossils have ever been found throughout the continent, making it difficult for scientists to understand their evolutionary history.
A team of Australian scientists led by the Australian Museum (AM) and University of New South Wales (UNSW) paleontologist Dr Matthew McCurry made a significant discovery. They found a giant fossil spider in Australia. It is the first fossil from the brush-footed trapdoor spider family ever found.
Scientists have formally named and described a fossil spider, Megamonodontium mccluskyi. According to their analysis, the fossil must be between 11 and 16 million years old.
Scientists discovered this fossil at McGraths Flat, NSW, a fossil site known for its iron-rich rock called ‘goethite.’ It is the first ever spider fossil of the Barychelidae family to be found. The spider was named for Dr. Simon McClusky, who discovered the specimen and is similar to the living genus Monodontium (a brushing trapdoor spider), though five times larger.
UNSW paleontologist Dr Matthew McCurry said, “This discovery of giant trapdoor spider fossil reveals new information about the extinction of spiders and fills a gap in our understanding of the past.”
“The closest living relative of this fossil now lives in wet forests in Singapore through to Papua New Guinea. This suggests that the group once occupied similar environments in mainland Australia but subsequently went extinct as Australia became more arid.”
Queensland Museum arachnologist Dr Robert Raven, who was the supervising author of the study, said this was the largest fossil spider to be found in Australia.
“Not only is it the largest fossilized spider to be found in Australia, but it is the first fossil of the family Barychelidae that has been found worldwide.”
“Around 300 species of brush-footed trapdoor spiders are alive today, but they don’t seem to become fossils very often. This could be because they spend so much time inside burrows and aren’t in the right environment to be fossilized.”
University of Canberra Associate Professor Michael Frese, who used stacking microphotography to scan the fossils, said, “the fossils from McGraths Flat show an amazing level of detailed preservation.”
“Scanning electron microscopy allowed us to study minute details of the claws and setae on the spider’s pedipalps, legs, and the main body. 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.”