The arid heart of Australia was once lush and teeming. The dense forests of the past were thick with life.
Paleontologists have found new evidence of life in one of the Central Tablelands. A new fossil site that can be described as exceptional has turned up fossils of arthropods, fish, plants, and even a bird feather, dating to 11 to 16 million years ago.
Matthew McCurry from the Australian Museum Research Institute said that the area was once a mesic rainforest and that life was abundant there.
Many of the fossils that we are finding are new to science and include trapdoor spiders, giant cicadas, was and a variety of fish. The level of preservation at this new fossil site means that even small fragile organisms like insects turned into well-preserved fossils.
There are plant fossils from McGraths Flat. Curry et al. Adv., 2022.
Sometimes even soft tissues have been preserved, as evidenced by the classification of the McGraths Flat as a Lagersttte, a sedimentary fossil bed that's so extraordinary that sometimes even soft tissues have been preserved. Some fossils can be made out of subcellular structures because of the well preserved organisms in McGraths Flat.
It's a type of rock called goethite, which is rich in iron and is not usually seen.
The process of turning these organisms into fossils is what makes them so well preserved. Our analyses show that the fossils formed when the iron-rich water drained into a billabong, and that a precipitation of iron minerals encased organisms that were living in or fell into the water.
The researchers said that the fossils are similar to the rainforests in Australia, but that the details make a difference.
The site's feather and melanosomes, the subcellular structures that give tissues their pigment, have been preserved in the eyes of fish and a fly.
A feather fossil. Michael Frese is a person.
The structure of unpigmented melanosomes can be compared to the structure of modern melanosomes to figure out how the tissues might have looked. The researchers can figure out what colors the various flat animals were.
Michael Frese of the University of Canberra said that the fossils preserve evidence of interactions between species.
We can figure out what the fish were eating with the preserved stomach contents. We can tell which plants are pollinating which insects by the preserved pollen on their bodies.
There are animal fossils in McGraths Flat. Curry et al. Adv., 2022.
The fossils may contain a hint of what's to come.
The rainforest of the McGraths Flat was being invaded by arid climate areas according to an analysis of the pollen grains. It was during this time that the Australian continent began to transform from lush to arid, as global temperatures began to rise.
Since global mean temperatures are rising, the environment in McGraths Flat could show how life might change in Australia's current rainforests in the years to come.
The Royal Botanic Gardens Victoria in Australia says that the fossils of the McGraths Flat plant give a glimpse into the vegetation and ecology of a warmer world.
The preservation of the plant is unique and provides important insights into a time period for which the fossil record in Australia is rather poor.
Science Advances has published the research.
