Controlled rock cutting explosions for the upgrading of a portion of a major national road in the Eastern Cape have led to the discovery of a treasure trove of fossils from an ancient river mouth ecosystem.

“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,” South African National Roads Agency Limited (Sanral) environmental manager Mpati Makoa said on Wednesday.

She noted that palaeontologist Dr Robert Gess of the Albany Museum in Grahamstown, who is a palaeontology heritage consultant to Sanral, had 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 supercontinent Gondwana nearly 360-million years ago, and when what is now the Eastern Cape was situated at high latitude, within 15˚ of the South Pole,” said Makoa.

According to Gess, the plant and invertebrate fossil discoveries were 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 km 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.

The team also retrieved the most complete specimens of the “fronds” of the Archaeopteris notosaria tree, which according to Gess was “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 clam 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, 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 freshwater input. They have never before been found in this age strata.”

OBSERVATION AREA
Sanral would build a rest and observation area for road users adjacent to the new paleontological heritage site.

The road design was being converted to accommodate a rest area that could be used as a picnic area. The area would feature information boards and displays on the significance of the fossils, their age and how they fit into the evolutionary history of earth.