Striking Miocene fossils unearthed in Australia

(ORDO NEWS) — All of them are surprisingly well preserved and can tell about the ancient past of the continent.

It’s not easy to survive in arid Australia today, but it was once covered with lush shrubs, green meadows and dense forests that were home to many animals.

New discovery, made by scientists on the central plateau of New South Wales, made it possible to verify this once again – and to look at the remains of an amazing paleofauna.

Researchers discovered fossils that can be called exceptional. Among them were spiders, insects, fish, plants and even bird feathers dating back to the Miocene epoch from 11 to 16 million years ago.

“The fossils we have found prove that the area was once a temperate rainforest and that life here was rich and abundant. Many of the fossils we find are new to science and include ctenisid spiders, giant cicadas, wasps and various fish. ”- Matthew McCurry, study co-author.

The complex, dubbed McGrats Flat, is so unique that it has been classified as lagerstett – a special type of burial of fossils, usually in large numbers, where, due to special conditions, not only hard parts of skeletal forms are preserved, but also imprints of soft tissues.

At McGrats Flat, animal and plant remains are so well preserved that even subcellular structures can be discerned in some fossils. Most surprisingly, they were found in goethite, an iron-rich type of rock that does not usually contain exceptional fossils.

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“We think the process that turned these organisms into fossils is the key to why they are so well preserved.

Our analyzes show that the fossils formed when iron-rich groundwater flowed into a stagnant body of water, and the deposition of iron minerals retained organisms that lived in or fell into the water. ”- Matthew McCurry.

The researchers said the fossils in the complex resemble the ecosystems of today’s Australian rainforest, but there is some difference in detail. For example, subcellular structures calledmelanosomesthat give the tissues their pigment are preserved in the fossilized feathers, as well as in the eyes of fish and flies.

Although melanosomes do not have pigment, their structure can be compared with the structure of modern melanosomes in order to understand what shade the tissues might have. This allows the researchers to figure out what color the different parts of the McGrats-Flat organisms were.

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“The fossils also contain evidence of interactions between species. For example, fish have preserved stomach contents, which means that we can figure out what they ate.

We also found samples of pollen preserved on the bodies of insects, and now we can understand which species which plants pollinated, ”- Michael Frese, co-author of the study.

Analysis of pollen grains in the complex indicates that the McGrats Flat rainforest has not experienced the transition to an arid climate. This was not a surprise to scientists: in the Miocene there was a global rise in temperature, and it was during this period that the Australian continent lost a huge mass of vegetation.

As global average temperatures rise, the McGrats Flat ecosystem could show us how life in Australia’s current rainforests could change in the coming years, the scientists write.

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