What Did Spiders Look Like 16 Million Years Ago? These are the fossil finds in Australia

A perfectly preserved fossil of a mygalomorph spider (Mygalomorphae, a type of tarantula in it) was discovered by researchers excavating at McGraths Flat, a site in New South Wales, Australia. The four-centimeter long spider is thought to have lived about 11-16 million years ago, when the area of the site is believed to have been a dense rainforest.

"This is not what we see living today in Australia," said research team member Matthew McCurry of the Australian Museum Research Institute .

As published in the journal Science Jan. 7, 2022, McCurry added, "One of its very distinct features is the size of its forelegs—it's an extremely large spider."

At McGraths Flat, researchers found equally well-preserved fossils of plants, insects and vertebrate animals. The site led archaeologists to dive into the appearance of Australia in the Miocene era. "The site maintains even the tissue structure within the specimen," said co-author Michael Frese of the University of Canberra.

By analyzing several leaf fossils, McCurry, Frese and their colleagues reconstructed the past climate in the region using computer modelling. Modeling brings up an annual mean temperature figure of around 17 degrees Celsius. They also found, from the modeling, that during the three wettest and driest months of the year, the monthly rainfall was between 962 and 254 millimeters respectively.

At the site the researchers also found evidence of interactions between organisms.For example, they found one freshwater clam

attached to the fin of a fish, which means the shell uses the fish to move around and find food.

They also found microscopic parasitic worms that appeared to have hitchhiked on the backs of long-horned beetles. "The level of fossil formation allowed us to get an unexpected picture into what this ancient rainforest ecosystem looked like," said McCurry, who is also a paleobiologist at the National Museum of Natural History, Smithsonian Institute, Wanshington, USA.

The McGraths Flat site, Frese added, has brought knowledge closer to prehistoric Australia. According to him, there are no other fossil sites that provide information on the Miocene period in Australia.

The Miocene period is considered very important because it was then that Australia began to turn a lot drier and almost all of its modern ecosystems began to develop. "This is arguably the origin story of Australia," McCurry said.

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