Grahamstown - A huge treasure trove of fossils, including of some species that have not been documented by scientists before, has been discovered during construction work on the N2 highway near Grahamstown.
"A number of new invertebrates, as well as excellently preserved plant fossils of the Devonian era, have been excavated and discovered in rock debris of the Witpoort Formation along the N2 between Grahamstown and Fish River," SA National Roads Agency Limited (Sanral) environmental manager Mpati Makoa announced on Wednesday.
The trove was discovered during "controlled rock cutting explosions".
Renowned palaeontologist Dr Robert Gess, who does consulting for Sanral, said the discovery was significant because "many species have not yet been documented by palaeontologists".
The Devonian era lasted from about 416 million years ago to 354 million years ago, and is often referred to as the "Age of Fishes" because of the varieties of fish that were spawned during that time.
Two large land masses at that time were the continent of Euramerica - which included what we now know as North America and Europe - and Gondwana, which was made up of South America, Africa, Antarctica, India and Australia.
The fossilised remains found during the roadworks are of life in a marine coastline environment when South Africa was part of Gondwana, nearly 360 million years ago.
"To advance scientific discourse and original research contributions of South African palaeontology and heritage scholars, we made provision in the environmental management programme for specialist examination and excavation of rock debris," Makoa said.
According to Gess, the plant and invertebrate fossil discoveries are from ancient open river mouth ecosystems.
"It differs from the fossil discoveries of the closed lagoon ecosystem of Waterloo Farm, an important South African paleontological heritage site of the late Devonian period which is 20km away from the current excavation site where Sanral is working," he said.
"The discovery is significant as paleontological research and scholarship on marine ecosystems of the Devonian period was primarily anchored in the fossil discoveries of Waterloo Farm. Now, we are able to trace a much broader picture of life along an ancient coastline through the discovery of new plant and invertebrate species."
He said the remains of a shrub sized "Iridopterid plant" were collected, as well as a number of "lycopods" and "Zosterophylopsid plants".
Complete specimens of the fronds of the "Archaeopteris notosaria" tree was also collected. Gess says this is the "best preserved fertile material of this ancient tree" on record.
Gess and his team also discovered new marine invertebrate fossils.
"We are busy describing a new species of bivalve or mud clams from Waterloo Farm. However, at the new outcrops we are dealing with an entirely different bivalve that has never before been found," he said.
Rest and observation area planned
Gess said roadworks in South Africa during 1985, 1999, 2008 and in 2016 have significantly shaped South African palaeontology research and studies.
"They have enabled discovery of the clues to virtually everything we know about high latitude latest Devonian life, not just in South Africa, but in the world," he said.
"Twenty late Devonian fish species would never before have been discovered had it not been for roadworks at Waterloo Farm."
He said between 20 and 30 types of fossil land plants, waterweeds and seaweeds have been collected from the rocks retrieved from roadworks at Waterloo Farm, and are being described by scientists. Some of the remains from Waterloo Farm include fragments of scorpions which represent the earliest known remains of land living creatures from the ancient supercontinent of Gondwana.
Sanral is now planning to create a "rest and observation" area for road users near the site.
"When we first met Dr Gess and he explained significant fossil finds, we thought how can we best preserve and allow public access to this to ensure it becomes general knowledge of what was in this area millions and millions of years ago?" said Steven Robertson, Sanral's project manager on the N2 Grahamstown to Fish River.
"So, we are converting the road design to accommodate a rest area that can be used as a picnic area, and we will be including information boards and displays on the significance of the fossils, their age how they fit into the evolutionary history of earth."