A local scientist has discovered the oldest fossil land animals from the Gondwana supercontinent in rocks he carted away from the N2 highway cutting just outside Grahamstown.
A local scientist has discovered the oldest fossil land animals from the Gondwana supercontinent in rocks he carted away from the N2 highway cutting just outside Grahamstown.
Dr Robert Gess this week revealed in the peer reviewed journal African Invertebrates his discovery of fossils representing a new species of scorpion (Gondwanascorpio emzantsiensis) that lived in these parts 360 million years ago. At that time, about 130 million years before the first dinosaurs walked the earth, there were two supercontinents, Laurasia in the north and Gondwana in the south.
When the Gondwana scorpion died, its body, which looked similar to its modern descendants, was rapidly covered in oxygen-depleted mud in an area that was only about 15 degrees (1 600km) from the South Pole. This might seem surprising as most modern scorpions are adapted to live in hot desert or sub-tropical to tropical climates, and would suggest that the Antarctic region was much warmer than it is today.
Gess explained that the scorpion fragments left impressions in the mud as it was transformed into black carbonaceous shale that remained undisturbed for hundreds of millions of years. The shale was eventually removed from the rocks on Waterloo Farm when a cutting on the N2 bypass was being repaired in 1999.
The age of the Gondwana scorpion is particularly significant because it is 90 million years older than the next oldest land-living animal fossils from Africa. Two other scorpion fossils of a similar age have been found, one in Canada which was then part of the other supercontinent, Laurasia and one in China.
Gess explained that his discovery is important because it is “the first page in the story of terrestrial animal life in Gondwana”. He said that the presence of the scorpions in the late Devonian Period is indirect proof of the presence of other terrestrial invertebrates as scorpions would have survived by preying on them.
Gess said that plants were the first life forms to come from the water onto land and they were closely followed by plant- and debris-eating insects and millipedes. These were in turn followed by predatory invertebrates such as scorpions that fed on the earlier colonists.
The story of how the 360-million-year-old scorpion fossils were found is interesting because had a state of emergency not been declared in 1985, they would probably still be in the ground. In terms of the state of emergency, an N2 bypass had to be built around Grahamstown.
The South African Defence Force (SADF) owned the land around the 6 SAI military base which would have provided the most rational route for the bypass, but the military refused to make any concessions. The bypass was then built through a hilly area that required the construction of bridges and road cuttings that were prone to rock slides. There were two serious rock slides in the ensuing years – one in 1999 and a second in 2007.
On both occasions the South African National Roads Agency Limited (Sanral) provided logistical support for Dr Robert Gess to remove tons of rocks that he believed could contain scientifically interesting fossils, before they sealed off the side of the cutting. He found the Gondwana scorpion while painstakingly chipping through rocks that he had carted off from the 1999 rock slide. He has also found numerous other fossils from a complex ancient estuarine ecosystem in the custom-built rock sheds in Bathurst.
Dr Robert Gess has dedicated this work to his father, Dr Fred Gess, one of South Africa’s leading entomologists who was based at the Albany Natural History Museum. Dr Fred Gess passed away on 6 August 2013.
