Rare fossils of early species found at SA sites

THEY would have provided a splash of greenery in a somewhat barren landscape not unlike that of Mars.

These plant species would have hugged the water’s edge and the tallest of them would have only reached ankle height, that is if humans were around then.

But what these plants were, were pioneers from which the land flora we know today would spring. They lived in what is now the Humansdorp area in the Eastern Cape, 420 million years ago, when the Earth was a harsh place, devoid of even soil.

It was a geological time known as the Devonian, when South Africa wasn’t where it is today, but sat close to the Antarctic circle. Temperatures, however, would have been warmer than today.

The imprints these plants left behind have survived and recently were discovered by Dr Rob Gess of the Albany Museum’s Devonian Lab in Makhanda, in the Eastern Cape. The fossils were found at a new dig site he had discovered.

Now scientists believe that this find represents Africa’s earliest known land ecosystem and provides a peek into a time when life was beginning its march from the briny oceans on to land.

In a recent article published in the journal Scientific Reports, Gess and coauthor Dr Cyrille Prestianni, of the Royal Belgian Institute of Natural Sciences, were able to pick out 15 plant species, three of which were unknown before.

But these plants are very different from what we know today. At the time, leaves had yet to evolve and plants didn’t have deep complete root systems.

Instead these plants were branching stalks on which sat spore containers.

“Some resembled miniature vuvuzelas, balls, clubs and some were castanet-shaped,” explains Gess.

What Gess hasn’t found as yet are any animals that might have lived among these plants. He suspects that small invertebrates were there and that it is a matter of time before he finds them in the fossil record.

The seas, however, would have teemed with life, including early fish that had only just evolved jaws and a host of invertebrates.

Until Gess’s discovery, only one species of plant from this age had been discovered in South Africa, and that was nearly 90 years ago. It is an indication of just how rare these fossils are.

There are only 23 fossil sites around the world that have produced plants from this time. And most of the fossils found, says Gess, contain the imprints of individual plants.

What also makes the new find important is that here is an example of an ecosystem from a high latitude near polar zone. Previous finds came from what was then the tropics.

Some 200km away on the outskirts of Makhanda, Gess has another dig site that he has been working on for years.

Here he has found fossils 60 million years younger than the ones discovered near Humansdorp. They still fall within the Devonian, but in paleo terms 60 million years is a blink of an eye.

When Gess compared what he had found at the two sites, it revealed just how quickly life established itself on land.

“So we go from really primitive ankle-high green fuzz around the edges of lakes, lagoons, and 60 million years later we have lovely cool shaded forests,” says Gess.

Gess’s discovery is a boon for South Africa, explains retired palaeontologist Professor Bruce Rubridge.

“It’s hugely exciting from a scientific perspective,” says Rubridge.