New fossil fruits rewrite plant evolutionary history
Scientists from CQUniversity and Queensland Museum have uncovered exceptionally preserved 30-million-year-old fossil fruits that are changing what we know about the evolution of tropical rainforest plants.
Discovered near Capella in Central Queensland, the fossil represents the world’s first known fossilised fruits from the Melastomataceae family, as well as the earliest evidence of this diverse tropical plant family in Australia, resulting in the identification of a new genus and species previously unknown to science.
Using advanced synchrotron imaging, researchers examined the fossil in remarkable detail, revealing microscopic soft tissues, internal fruit anatomy and hundreds of preserved seeds.
The newly described fossil, Capella raulingsii, was found in 28–30-million-year-old silcretes (an extremely hard, silica-rich rock that forms naturally near the Earth's surface), near Capella in Central Queensland.
Preserved through rapid silicification during ancient volcanic activity, the fossils contain exceptionally detailed soft-tissue anatomy, making them the oldest known three-dimensional Melastomataceae fruits in the world.
Queensland Museum Principal Scientist of Geosciences and Adjunct Research Fellow at CQUniversity Dr Andrew Rozefelds said the paper overturns long-standing assumptions about how and when these plants reached Australia.
“These fossils show that members of the Melastomataceae were growing in Australia tens of millions of years before the continent made contact with Southeast Asia,” Dr Rozefelds said.
“It provides the first concrete evidence these plants were part of eastern Gondwana's ancient rainforests, and it forces us to rethink the historical biogeography of the entire family.”
He said it also provided a rare insight into rainforest evolution in northern Australia during the Early Oligocene.
"The preservation is extraordinary. We can see internal structures that are almost never preserved in fossil plants, allowing us to identify an entirely new genus and species," Dr Rozefelds said.
Using high-resolution synchrotron imaging, researchers reconstructed the internal structure of the fruit in remarkable detail, allowing them to identify features that link Capella raulingsii to modern tropical shrubs and vines found across northern Australia and Southeast Asia.
Queensland Museum CEO Renai Grace said this paper showcases outstanding scientific research happening within Queensland Museum.
“This is world-class science happening right here in Queensland,” Ms Grace said.
“Our researchers are revealing extraordinary chapters of Earth’s history and scientific papers like this highlight the global importance of Queensland’s fossil heritage.”
The Capella fossil flora is considered one of Australia’s most diverse assemblages of silicified seeds and fruits, offering a rare glimpse into the forest structure of these ancient rainforests.
The species name, raulingsii, recognises the Raulings family for their philanthropic support of the research.
The paper was recently published in the open access journal International Journal of Plant Sciences International Journal of Plant Sciences.
