Two new tetrapod species were identified in the Devonian locality, the Tutusius, and Umzantsia, and they the earliest known four-legged vertebrates ever to exist in Africa.
According to the researchers, both Tutusius and Umzantsia presented the characteristics of primitive amphibians, namely, four legs and an alligator-like body with fish-like characteristics.
Both of the amphibians were reportedly are in the category of early tetrapods, and they are in the groups which encompass all the terrestrial vertebrates.
The latest fossil discovery of the meter long Tutusius umlambo, which is named after nobel peace prize victor Archbishop Emeritus Desmond Tutu, and Umzantsia amazana means their terrestrialisation could have happened anywhere.
First of all, these creatures lived during the Devonian Period (420-359 million years ago) and, as Devonian tetrapods, they are among the earliest ancestors of all vertebrates alive today: mammals, birds, and amphibians.
The research was supported by the South African DST-NRF Centre of Excellence in Palaeosciences‚ based at the University of the Witwatersrand and the Millennium Trust.
The Waterloo Farm fossil site was revealed in 1985 after controlled rock-cutting by the South African National Roads Agency (Sanral) along the N2 highway south of Grahamstown. This cutting exposed dark grey mudstones of the Witpoort Formation that represent an ancient environment of a brackish, tidal river estuary that contain abundant fossils of animals and plants.
At the same time, "Umzantsia" refers to the southern region where the species was found and "amazana" means "water ripples", pointing to the "very distinctive ornaments on the bone", says the paleontologist.
Until now, it was widely accepted that creatures first stepped foot on land in a tropical supercontinent called Laurasia, which included modern-day North America, Greenland and Europe.
"Now we have evidence of two types of Devonian tetrapod from the other end of Gondwana, on the other side of the South Pole, in the Antarctic Circle", Dr Robert Gess, one of the leading researchers, told AFP. The only fossil found of these amphibian tetrapods was a jaw and footprints in eastern Australia. The creatures lived in what was then the southernmost part of the super-continent Gondwanaland, which extended 70% south to within the Antarctic Circle and later broke up into several continents, including Africa. This finding changes our understanding of the distribution of Devonian tetrapods. We now know that tetrapods occurred throughout the world by the Late Devonian and that their evolution and terrestrialisation could realistically have occurred anywhere.
The earliest tetrapods discovered outside of tropical and sub-tropical zones, the fossils were unearthed at a site called Waterloo Farm in South Africa.
"There is probably not another country that so fully documents the long and dramatic evolutionary history of our own lineage", Gess said.