Fossil leaves should make waves
Scientists are only scratching the surface of South Africa's plant fossil heritage, said Dr Rose Prevec during her talk at the Albany Museum last week. She said that ancient forests from the Permian Period (299 to 252 million years ago) in what is now the Karoo, have barely been studied.
When new dinosaur bones are discovered, or a type of ancient human ancestor is found in a cave, scientists, the media and the general public can become very excited. However, when a rich new site of fossil leaves is discovered, it is much harder to get the public’s attention.
Prevec is one of two palaeobotanists currently employed in South Africa. The only other member of this rather rare breed is Prof Marion Bamford who works for the Evolutionary Studies Institute at the University of the Witwatersrand. The profession is soon to have a third member as Aviwe Matiwane is currently studying fossil Glossopteris leaves as part of her PhD research.
Prevec was speaking about the importance of these ancient forests to our present economy as part of a lecture series on the earth sciences. She explained that plant material deposited during the Permian Period was transformed into coal through a slow process involving burial, compression, heating and chemical alteration. Coal formed over millions of years is today the prime generator of electrical energy in South Africa and therefore a key driver of our economy.
Matiwane gave the final lecture of the four-part series focusing on recent discoveries of Glossopteris fossils near the town of Sutherland in the Northern Cape.
Glossopteris is a genus of more than 70 shrubs and trees that thrived during the Permian but abruptly disappeared in the largest ever extinction event at the end of that period. This plant derived its name from the Greek work "glossa" which means tongue because the leaves are usually shaped like a long tongue.
The plants took various forms with some trees reaching up to 30m tall. When they were first discovered it was believed that they were a type of fern, but currently glossopterids are placed in with the gymnosperms (conifers, cycads and others).
Glossopteris fossils have been found in Southern Africa, South America, India, Australia and Antarctica. Their presence in these different land masses provide compelling evidence of the existence of the Gondwana super continent during the Permian Period.
At the time when Glossopteris trees dominated the Gondwana landscape, the world looked very different to what we might expect today. We would be surprised to find out that there was no grass on the ground, no flowers anywhere at all, no birds, no true mammals and the dinosaurs were still far off in the future.
Glossopteris leaves from the Late Permian Period (approximately 252 million years old) taken from a railway cutting in northern KwaZulu-Natal, near Richards Bay.
Dr Rose Prevec, Curator and Head of the Department of Earth Sciences at the Albany Museum.