Australia’s oldest angiosperms (flowering plants) are approximately 126 million years old, and they resembled modern magnolias, buttercups and laurels, according to new research published in the Review of Palaeobotany and Palynology.
Rocks containing microscopic pollen were collected to determine the age of fossil leaves from Castle Cove, Otway Ranges, Victoria, Australia. Image credit: Vera Korasidis.
“Our research, completed on dinosaur-bearing rocks throughout Victoria, suggests that warming temperatures allowed the first flowering plants to migrate to the cooler regions at the Earth’s poles,” said Smithsonian Institution researcher Vera Korasidis, who performed the study while she was a research assistant at the University of Melbourne.
“The true diversity of primitive flowers in southern near-polar settings has only just been discovered because ‘sieving’ practices resulted in pollen grains, produced by the earlier flowers, being ‘rinsed down the sink’ for over 50 years.”
In the study, Dr. Korasidis and her colleague, University of Melbourne’s Dr. Barbara Wagstaff, analyzed the fossilized pollen and leaves of ancient angiosperms from numerous sites — such as the Otway and Gippsland basins — in Victoria, southeastern Australia.
“We reconstructed our earliest flower-bearing forests, from 126-100 million years ago (Cretaceous period), to conclude that climate change prevented or slowed the expansion of flowers into Australasia with the temperatures at the high southern latitudes too cold to support the earliest flowering plants,” they explained.
“We also established that the first flowers related to 72% of today’s living angiosperm species that first appeared in southern Australia about 108 million years ago — 17 million years after the first flowers evolved in equatorial regions,” they said.
“The world’s oldest flower, Montsechia, is 130 million years old and was discovered in Spain.”
“Our study would help to piece together Australia’s paleoclimate record and understand the interaction between climate, carbon dioxide and the evolution of faunas and floras,” Dr. Korasidis said.
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Vera Korasidis & Barbara Wagstaff. 2020. The rise of flowering plants in the high southern latitudes of Australia. Review of Palaeobotany and Palynology 272: 104126; doi: 10.1016/j.revpalbo.2019.104126
