Controlled rock cutting explosions for the upgrading of a portion of a major national road in the country’s Eastern Cape province has opened a fossiliferous shale treasure trove of an ancient river mouth eco-system, the South African National Roads Agency SOC Ltd (SANRAL) announced today.
“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,” announced Mpati Makoa, SANRAL’s environmental manager today.
Makoa said that renowned South African palaeontologist Dr. Robert Gess of the Albany Museum in Grahamstown, a palaeontology heritage consultant to SANRAL, indicated that the discovery was significant as “many species have not yet been documented by palaeontologists.”
“The fossilised remains are of life in a marine coastline environment when South Africa was part of the super continent Gondwana nearly 360 million years ago, and when what is now the Eastern Cape was situated at high latitude, within fifteen degrees of the South Pole,” she said.
“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. The potential for such significant finds had already been identified in the environmental impact assessment,” she said.
According to Dr.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 palaeontological heritage site of the late Devonian period which is 20 kilometres away from the current excavation site where SANRAL is working.
“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.
“We have collected the remains of a shrub sized Iridopterid plant, from the group that was ancestral to modern horsetail plants. Interestingly, while Iridopteralians were located both at Waterloo Farm and the current fossil excavation site, they are different, though both are undescribed species.
“In addition, a number of types of clubmosses (lycopods) that formed patches of knee height branching stalks resembling bristling cat’s tails have been discovered and collected at the current site, as well as Zosterophylopsidplants,”he said.
The team also retrieved the most complete specimens of the ‘fronds’ of the Archaeopterisnotosaria tree, which according to Dr. Gess is “the best preserved fertile material of this ancient tree” on record.
Dr. 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.
Just a few kilometres west of the main plant fossil localities and in slightly older strata, Dr. Gess and his team also discovered linguloid brachiopod shells.
“Linguloid brachiopods were invertebrates that lived in burrows and had a long fleshy foot. When found without other types of marine invertebrates they indicate a marine environment with some fresh water input. They have never before been found in this age strata.”
SOUTH AFRICAN ROADWORKS INSTRUMENTAL TO SHAPING PALEONTOLOGICAL KNOWLEDGE
According to Dr. Gess, roadworks in South Africa during 1985, 1999, 2008 and now again this year 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.
“Twenty late Devonian fish species would never before have been discovered had it not been for roadworks at Waterloo Farm.
“Furthermore, between twenty and thirty types of fossil land plants, water weeds and seaweeds have been collected, from the rocks retrieved from roadworks at Waterloo Farm, and are being described by scientists. Invertebrate remains from Waterloo Farm include fragments of scorpions which represent the earliest known remains of land living creatures from the ancient super continent of Gondwana,” he said.
Dr Gess explained that the black shale in which the fossils are found is very prone to weathering and in nature is turned to formless clay before it reaches the surface of the ground.
“Roadworks, though, give the opportunity for palaeontologists to, as it were, reach deep into the landscape and retrieve fresh unweathered shale,” he said.
NEW REST AND OBSERVATION AREAS PLANNED ALONG N2 TO PROMOTE RICH PALEONTOLOGY HERITAGE OF REGION
SANRAL is planning a rest and observation area for road users adjacent to the new paleontological heritage site, according to Steven Robertson, SANRAL project manager on the N2 Grahamstown to Fish River.
“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?” he said.
‘’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,” he noted.