The new specimen represents the first occurrence of an acipenseriform (sturgeon) fish on the continent of Africa.
The European sea sturgeon (Acipenser sturio). Image credit: Alexander Francis Lydon.
Sturgeon is the common name for almost 30 species of fish belonging to the family Acipenseridae.
These fishes have long been valued for their meat and row, which are eaten as caviar.
But as a result of overfishing, along with habitat loss, many species are critically endangered. And several are on the verge of extinction in the wild.
Sturgeons are often regarded as a living fossil because their ancestors date back to the same time that dinosaurs roamed, over 200 million years ago.
They can grow up to 7 m in length and reach a weight of 1.5 tons, although such sizes are exceedingly rare today.
“The very first sturgeons appear in the fossil record in the Late Triassic period in China,” said Professor David Martill, a paleontologist at the University of Portsmouth.
“But the oldest true sturgeon ever discovered is probably a specimen in the Steve Etches collection from Dorset’s Jurassic Coast in England.”
“The new Moroccan species complicates models of the location of the origin of this important group of fish that is typically so widespread in the northern hemisphere.”
The bony scute of the Cretaceous sturgeon species from Morocco. Image credit: David M. Martill, doi: 10.1016/j.cretres.2023.105546.
A single bony scute of the new sturgeon species was found in the uppermost Cretaceous marine phosphatites of central Morocco.
The discovery of this fossil in Africa is particularly significant because it is the first of its kind to be found on the continent, suggesting that sturgeons were once more widespread than previously thought.
“I noticed the fossil when I was visiting a well-known Moroccan fossil site during a field trip in November 2022,” Professor Martill said.
“I found a piece of rock with bucklers, the bony external plates found on these heavily armored fish, and I knew straight away it was a sturgeon.”
“It was a surprising discovery because all sturgeon species have been exclusively found in the northern hemisphere in the past.”
“They’ve been located in North America, Europe, Asia, Chinese Asia, but never in South America, Australia, Africa or India, which are the land masses that made up Gondwana, a supercontinent that existed around 336 million years ago and began breaking up around 150 million years ago.”
The discovery is described in a new paper published March 30, 2023 in the journal Cretaceous Research.
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David M. Martill. A sturgeon (Actinopterygii, Acipenseriformes) from the Upper Cretaceous of Africa. Cretaceous Research, published online March 30, 2023; doi: 10.1016/j.cretres.2023.105546
