Fossil plants could help Rhodes University PhD researcher solve a 200-year puzzle

Paleobotanist Aviwe Matiwane on site (Onder Karoo,[-]
South Africa), finding fossil plants. 
Paleobotanist Aviwe Matiwane on site (Onder Karoo,[-] South Africa), finding fossil plants. ROSE PREVEC

Andrew Wight, Australian Science Journalist. 

Paleobotanist Aviwe Matiwane is working in her native South Africa to find and catalog fossils of a plant that can provide us with a glimpse back in time to the climate and even food chains of a time before the dinosaurs.

Matiwane, who is a PhD researcher at Rhodes University and Albany Museum in South Africa, says that Glossopteris has no living relatives, but was an early example of a gymnosperm, that is, a plant that uses an exposed seed to reproduce, rather than a fruit.

This fossil plant was around during the Permian, a period 252-299 million years ago, and in addition to now forming the oldest coal deposits in South Africa, the plants have been used to solve a wide-range of scientific mysteries.

Glossopteris can tell us so much about the past: For example in some cases stomatal studies have been used to model Carbon Dioxide (CO2) changes during the Permian and these are used to inform researchers about the climate conditions during that time period,” she said, “Glossopteris can also be a link to prehistoric food chains, as feeding patterns preserved on the fossil impressions together with the fossil insects found can help researchers link animal-plant interactions.”

Matiwane says fossils of the plant also support the concept of continental drift – the now-accepted theory that the continents once formed one massive landmass and have drifted apart over time – because the fossils have now been found in all the southern continents: Australia, Antarctica, India, South Africa, and South America.

“My work involves finding the best descriptive features to identify and name Glossopteris leaves because taxonomic approaches used to differentiate these leaves vary, most descriptions of these fossil plants rely on visual estimations of relatively few characteristics.” she said, adding that species identification has proven to be subjective, inconsistent and extremely challenging.

Matiwane says that the most important part of her study is to solve the 200-year-old problem of how to classify and organise Glossopteris leaves.

“My work considers new approaches involving morphometric and ecological techniques with the aim of establishing a standardized methodology for the leaf taxonomy of this group,” she said, “I am also developing a national and international online leaf description database which will be used by researchers across the world.”

Matiwane says her work is important because she is describing the first conclusive middle Permian flora in South Africa.

“The study site is in Ouberg Pass (near Sutherland) this will contribute towards the greater goal of establishing a reliable biostratigraphic framework for Glossopteris floras of the Permian of the Karoo Basin,” she said.

Matiwane says growing up in a small village in South Africa’s Eastern Cape Province, she always loved plants and that walks with her grandfather as a formative moment.

“My grandfather is a self-taught botanist and he used to take me on walks in the forest and show me the different types of plants and some of their uses,” she said, “I was always intrigued about the evolution of plants but having grown up in a rural village I never knew there was such a field as botany.”

She eventually obtained both an Honours and Master of Science degrees at Rhodes University in South Africa, looking at the plant biodiversity of the Southern Mistbelt Forests of the Eastern Cape.

Matiwane says there is not much known about the broader fields of palaeoscience among the South African public even though fossils are part of the country’s national heritage.

“The public may know about dinosaurs however, not about the fossil plants” she said, adding that one of the biggest challenges is getting people to appreciate our wonderful fossil heritage.

“Also dealing with discrimination and racism as a Black woman in the field has been tough,” she said.  

Matiwane says one of the biggest opportunities so far has been to the National Museum of Natural History, Paris, where she got to work on some of the original Glossopteris specimens,

“But most importantly, I get to show kids that scientists come in different shapes, sizes, and form,” she said, “I am not the generalized/typical lab coat scientist you see in your Google searches.”

Matiwane is one of a new generation of female paleontologists in the developing world. Another is Catalina Suarez, a Colombian geologist and paleontologist, who studies fossils of ancient mammals, their paleobiology and paleoecology, searching for clues to understand how climate change affects diversification and extinction rates in mammals.