Roadworks near Grahamstown lead to discovery of fossils

01 Jun 2016 | Admin Author

Blasting and excavation for roadworks near Grahamstown has unearthed a treasure trove of fossils dating back millions of years.According to paleontologist, Dr Robert Gess, the discovery a fortnight ago is significant as many species have not yet been documented or described in academic literature.

Gess, a heritage consultant for the SA National Roads Agency Limited, said they found a number of invertebrates and excellently preserved plant fossils of the Devonian era.
The fossils were found during blasting for the new portion of the N-2 between Grahamstown and Fish River on a Sanral road construction site.Gess, a scholar at the Albany Museum, said the fossilised remains are of life in a marine coastal environment when South Africa was part of the supercontinent Gondwana, some 360 million years ago.

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 Zosterophylopsid plants,"he said.According to a statement from the SA National Roads Agency Limited, "the team also retrieved the most complete specimens of the 'fronds' of the Archaeopteris notosaria tree, which according to Dr. Gess is "the best preserved fertile material of this ancient tree" on record."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."

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, waterweeds 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 supercontinent 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 paleontologists to, as it were, reach deep into the landscape and retrieve fresh unweathered shale," he said.

SANRAL's environmental manager, Mpati Makoa, said "to advance scientific discourse and original research contributions of South African paleontology 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."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.
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