Science and Technology Minister Mmamoloko Kubayi-Ngubane, together with South African palaeontologist Dr Rob Gess, on Friday announced the discovery of the first African fossils of Devonian tetrapods, or four-legged vertebrates.
The two new species, named Tutusius umlambo, after Archbishop Emeritus Desmond Tutu, and Umzantsia amazana, are Africa’s earliest known four-legged vertebrates at 360-million years old, 120-million years older than the first dinosaur discoveries in the region.
“Whereas all previously found Devonian tetrapods came from localities which were in tropical regions, these specific specimens lived within the Antarctic circle,” Gess said at the launch.
The 1-m-long Tutusius, and the somewhat smaller Umzantsia are both incomplete fossils.
Tutusius is represented by a single bone from the shoulder girdle, whereas Umzantsia is known from a greater number of bones, but they both appear similar to previously known Devonian tetrapods.
“Alive, they would have resembled a cross between a crocodile and a fish, with a crocodile-like head, stubby legs and a tail with a fish-like fin,” Gess explained, adding that their evolution was the result of an adaptation of living in shallow lakes and lagoons.
The tetrapods were discovered after a roadcut in 2016, during controlled rock-cutting explosions by the South African National Roads Agency along the N2 highway between Grahamstown and the Fish River, in the Eastern Cape, at the Waterloo Farm.
The cutting exposed dark grey mudstones of the Witpoort Formation that represented an ancient environment of a brackish, tidal river estuary containing abundant fossils of animals and plants.
The real importance of Tutusius and Umzantsia lies in where they were found, he said.
Gess explained that Devonian tetrapod fossils are found in widely scattered localities; however, if the continents are mapped back to their Devonian positions, all previous finds are from rocks deposited in Laurussia, a supercontinent that later fragmented into North America, Greenland and Europe.
The much larger southern supercontinent, Gondwana, which incorporated present-day Africa, South America, Australia, Antarctica and India, has yielded almost no Devonian tetrapods, with only an isolated jaw and footprints, being found in eastern Australia.
“The Waterloo Farm tetrapods not only come from Gondwana, but from its southernmost part, reconstructed to have been more than 70º south, within the Antarctic circle,” he said.
Kubayi-Ngubane, meanwhile, said South Africa was richly endowed with natural resources, and the country's fossil wealth dated back more than three-billion years.
"It is uniquely expansive for any one country and many internationally significant fossil discoveries have been made in our country and are stored in South African museum collections," she said.
She added that the country's geographic advantage as a global provider of information on the evolution of life and humanity on Earth stood alongside the country's biodiversity and geographic advantage in astronomy, and the science of the southern oceans.
“Work on South African paleosciences is of crucial national and international importance, because it provides proof of our shared human origins, which are the mutual roots that bind all people within a common humanity,” she said.
The Minister added that it also provided answers as to what occurred before humans existed, including the evolution of plant and animal life, noting that this latest discovery placed South Africa at the forefront of the study of the evolution of land-living vertebrate animals, including the ancestry of all the wildlife in the country's game parks.
“The discovery further confirms the evolution from fish to humans,” Gess said.