During the Upper Cretaceous era, about 66 million years ago, this huge coelacanth plowed through the waters just before the dinosaurs disappeared.
In Morocco, researchers discovered a 66-million-year-old fossilized lung of a previously unknown ancient fish species , as large as a great white shark. Analyzes suggest that the fish was a much larger member of the coelacanths, an order of fish nicknamed ‘living fossils’ that were thought to be extinct until a living specimen was found in 1938.
The discovery was quite fortuitous. They asked Professor David Martill, a paleontologist at the University’s School of Environment, Geography and Geosciences, to identify a large bone in a private London collection. The collector had bought the specimen thinking that the bone might have been part of a pterodactyl skull. Nothing could be further from the truth: the rock was made up of many thin bony plates.
“The thin bony plates were arranged like a barrel, but with the staves turning instead of up and down. Only one animal has that structure and that is the coelacanth; we had found a bony lung of this extraordinary and strange looking fish.” says Martill.
A giant coelacanth
According to the size of the newly discovered fossilized lung, found in phosphate beds in Oued Zem in Morocco, this coelacanth was 5.2 meters long, experts point out in their study published by the journal Cretaceous Research ; substantially larger in size than modern coelacanths, which only grow to a maximum length of 2 meters. Along with the fossilized lung they found other bones belonging to pterosaurs.
” The specimen is also the first record of a marine coelacanth in Mesozoic Morocco and the first appearance of coelacanths in North African phosphate deposits, ” the researchers said. “We only had one lung, albeit massive, so our conclusions required some pretty complex calculations. It was amazing to deduce that this particular fish was huge, well over the length of a paddle board, and probably the largest coelacanth ever discovered. ”.
Apparently, this unnamed species is still believed to have lived in the open sea unlike other previously discovered ancient coelacanths that lived in rivers and were about 3-4 meters long.
“The body plan of the coelacanth has been fairly constant for the past hundreds of millions of years,” Martill said. “This is much bigger.”
The new discovery sheds light on one of the most mysterious groups of fish to ever swim in the oceans, but it also raises questions about what happened to them. How he died? Where is the rest of your body? According to the researchers, some of the large reptilian marine predators that dominated the Cretaceous oceans, such as plesiosaurs and mosasaurs, may have eaten it.
“Coelacanths were slow-swimming fish; this massive version would have been easy prey for these large predators,” says Martill.
The fate of this species remains a mystery, as they disappear from the fossil record at the end of the Cretaceous period.
Referencia: Paulo M. Brito et al. 2021. A marine Late Cretaceous (Maastrichtian) coelacanth from North Africa. Cretaceous Research 122: 104768; doi: 10.1016/j.cretres.2021.104768
