In the dry heart of the continent, scientists have found a beautifully preserved fossil spider of impressive size that roamed and hunted in lush rainforests. But it’s not just any fossil: this is only the fourth spider fossil found in Australia, and the first worldwide, from a spider in the Barychelidae family of large clog trapdoor spiders.
It has been preserved in exceptional condition
The official name of the new species that lived 11-16 million years ago, in the Miocene, is Megamonodontium mccluskyi. origo.hu.
So far, only four spider fossils have been found on the entire continent, making it difficult for scientists to understand their evolutionary history.
– Paleontologist Matthew McCurry, a colleague of the University of New South Wales and the Australian Museum, told the online science portal ScienceAlert. This is why this discovery is so important, as it reveals new information about the extinction of spiders and fills a gap in our understanding of the past.
He added that the closest living relatives to the fossil now live in humid forests from Singapore to Papua New Guinea, suggesting that the group once inhabited a similar environment on the Australian mainland but later became extinct as Australia became drier.
The spider was discovered among a rich collection of Miocene fossils found in a grassland area of New York known as McGraths Flat.
It is so exceptional that it has been classified as a Lagerstätte, a sedimentary fossil layer that sometimes preserves soft tissue. Some fossils from McGraths Flat even show subcellular structures.
The whole thing is made even more surprising by the type of rock found here: it’s an iron-rich rock type called goethite, in which exceptional fossils are rarely found.
However, it has now been shown that the preservation was so detailed that researchers were able to pick out small details of the spider’s body: they were thus able to confidently identify a member of the modern genus Monodontium, but about five times larger in size. .
We can also see hair-like structures
According to a study published in the Linnean Society Zoological Journal, Monodontium is usually small in size, but it is still the second largest spider fossil ever found worldwide.
Megamonodontium mccluskyi had a body length of 23.31 mm, which could fit comfortably in the palm of our hand with its legs spread wide.
The ancient animal’s massive size makes the detailed preservation of its physical characteristics even more impressive.
The scanning electron microscope allowed us to study the fine details of a spider’s claws, legs, and claws.
– explained virologist Michael Freese from the University of Canberra, who examined the fossils using overlaid microscopic images. “We can also see hair-like structures that could have many functions: they can sense chemicals and vibrations, protect the spider from attackers, and even make sounds.”
The discovery may also provide answers about how Australia changed over time when the landscape dried out dramatically.
There are no Monodontium or Megamonodontium spiders living in Australia today.
Experts indicate that drought during and after the Miocene era was responsible for the extinction of certain families of spiders.