Spider fossils tell Australia's 'origin story'

Researchers found a well-preserved fossil of a mole spider at a fossil site in the McGrath Plains of New South Wales, Australia. The 4-centimeter-long spider lived about 16 million to 11 million years ago, when the area was still covered by dense rainforest. The relevant paper was recently published in Scientific Progress.

"It's unlike any animal we see in Australia today." Author Matthew McCurry, of the Australian Museum Institute in Sydney, said: "One of the distinctive features is the size of the first set of legs – it's a very large spider. ”

The discovery of an equally well-preserved set of plant, insect and vertebrate fossils in The Macgrath Plains has given researchers an unprecedented understanding of what Australia looked like during the Miocene.

"The fossils even preserve the soft-tissue structure inside the specimen." Author Michael Frese of the University of Canberra said.

By analyzing the properties of several fossil leaves from the site, the researchers used computer models to reconstruct the area's past climate. The average annual temperature in the region is about 17°C. They also found that during the wettest and driest 3 months of the year, monthly rainfall was about 962 mm and 254 mm, respectively.

In addition, the researchers found evidence of interactions between organisms. For example, a freshwater mussel attaches to a fish fin, which means that the mussel uses the fish to move and eat. They also found a tiny parasitic nematode under the microscope that appeared to ride a free ride on a long-horned beetle.

"The degree of bio-petrochemicalization allows us to gain insight into these ancient rainforest ecosystems." McCurry said.

The site also fills a gap in Australian prehistoric knowledge. "We didn't have fossil sites to provide information about Australia's Miocene, which was an important period." Frese said.

"Australia was getting drier at the time, and most of the modern ecosystems were developing." McCurry said, "In a way, this is the origin story of Australia. (Li Muzi)

Source: China Science Daily