March 7, 2021

Ancestral fish fossil so large it was attributed to a pterodactyl discovered


The original slab, as purchased, with the ossified coelacanth lung

The original slab, as purchased, with the ossified coelacanth lung
University of Portsmouth

Fossilized remains of the lung of a fish that grew as big as a great white shark, and the largest of its kind ever found, have been discovered by chance. The new discovery made by scientists at the University of Portsmouth is a species of the so-called coelacanths that they still swim in the seas, surviving the extinction that killed the dinosaurs.

The discovery was purely fortuitous. Professor David Martill, a paleontologist at the University’s School of Environment, Geography and Geosciences, was asked to identify a big bone in a private London collection. The collector had bought the specimen thinking that the bone could have been part of the skull of a pterodactyl. Professor Martill was surprised to find that it was not actually a single bone, but composed of many thin bony plates.

He said: “The thin bone plates were arranged like a barrel, but with the staves rotating instead of top to bottom. Only one animal has such a structure and that’s the coelacanth; We had found a bony lung from this remarkable and strange-looking fish. “The collector was very disappointed that he did not have a pterosaur skull, but my colleagues and I were excited because coelacanth had never been found in phosphate deposits in Morocco, and this example was absolutely huge!”

Professor Martill teamed up with prominent Brazilian paleontologist Paulo Brito, from Rio de Janeiro State University, to identify the fossil. Brito has studied coelacanths for more than 20 years and is an expert on their lungs, and was in awe of the size of this new specimen.

The fossil had been embedded in a phosphate block, covered with plaster and covered with a layer of lacquer, which had made the bones turn brown. It was found next to a pterodactyl that proves it lived in the Cretaceous era, 66 million years ago.

The private owner offered to cut the remains of the bone lung from the slab and hand it over to the team for free. They then had to remove the coating and further expose the bones using specialized equipment, which included dental tools and fine brushes.

Professor Martill and his colleagues were able to determine that they had found a surprisingly large coelacanth due to the abnormal size of the lung. They calculated that it could have been five meters long, substantially larger than the rare and threatened modern coelacanths, which only grow to a maximum length of two meters. “We only had one lung, albeit massive, so our conclusions required some pretty complex calculations. It was surprising to deduce that this particular fish was huge, far longer than the length of a standing paddle board and probably the longest coelacanth. greatest ever discovered, “he explained.

Coelacanth fish They first appeared (evolved) 400 million years ago, 200 million years before the first dinosaurs. It was long believed to be extinct, but in 1938 a living coelacanth was found off South Africa.

The fossil is now being returned to Morocco, where it will be added to the collections of the Geology Department of Hassan II University of Casablanca. The research is published in Cretaceous Research.

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