Not so fishy: Africa's first ever fish-with-legs discovered

07 June 2018 - 20:07 By Tanya Farber

The Centre of Excellence in Palaeosciences based at the University of the Witwatersrand today announced the discovery of two new Devonian tetrapod species and the first Devonian tetrapods discovered in Africa (8 June 2018). The species have been named Tutusius umlambo (named in honour of Archbishop Emeritus Desmond Tutu) and Umzantsia amazana and were discovered by Dr Rob Gess of the Albany Museum and supported by the Millenium Trust.

An extraordinary find has been made near the university town of Grahamstown in the Eastern Cape.

Up until today‚ when a paper was published in Science‚ it was believed that Devonian tetrapods (fish that had developed four legs as the evolution from aquatic to land animals began) had only existed in the tropics.

But‚ in a groundbreaking study that shakes up our entire notion of the moment we adapted to move beyond the water‚ it has now been discovered that that is simply not true.

The newly discovered tetrapods - which 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 - were found in the Devonian Waterloo Farm near Grahamstown‚ and were living within the Antarctic circle some 360 million years ago.

The two new species are named Tutusius and Umzantsia. The metre-long Tutusius umlambo‚ named in honour of Archbishop Emeritus Desmond Tutu‚ and the somewhat smaller Umzantsia amazana‚ are both incomplete.

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.

This find represents two dramatic shifts. Firstly, it means the first appearance of tetrapods on African soil shifts to 70-million years earlier than thought‚ but it also means that one of the most fundamental understandings of our shift from the water to the land has to be reassessed.

The evolution of tetrapods from fish during the Devonian period was a major turning point in our ancestry‚ and all research on that turning point has up until now‚ hinged on the fact that this happened (or so we thought) between 30 degrees north and south of the equator. Almost all come from Laurussia‚ a supercontinent that later fragmented into North America‚ Greenland and Europe.

“Whereas all previously found Devonian tetrapods came from localities which were in tropical regions during the Devonian‚ these specimens lived within the Antarctic circle‚” explains lead author‚ Dr Robert Gess of the Albany Museum in Grahamstown‚ and co-author Professor Per Ahlberg of Uppsala University in Sweden.

Minister of Science and Technology‚ Mmamoloko Kubayi-Ngubane‚ congratulated Dr Gess‚ saying this groundbreaking discovery places South Africa at the forefront of the study of the evolution of land-living vertebrate animals‚ including the ancestry of all the wildlife we see in the country's game parks.

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.


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