Coelacanths are fish (sarcopterygii) that appeared during the Devonian about 410 million years ago. Widespread in different aquatic environments, this order was believed to have been extinct since the Cretaceous, an era in which they could grow up to 3 metres long. In 1938, however, a first specimen was found at the mouth of the Chalumna River near the coast of South Africa, and a second was found in 1952 in the waters of the Comoros. This is why coelacanths are sometimes called "living fossils".
Marjorie Courtney-Latimer was in charge of a small natural science museum in the city of East London (South Africa) and often examined the fish brought to port by a trawler, whose captain was a friend of hers. Discovering a strange, yet magnificent, blue fish, until that timeunknown, she kept the specimen and informed Professor J.L.B. Smith of her discovery. Smith recognised the coelacanth and the news of the discovery was a bombshell. Smith baptised the speciesLatimeria chalumnae, in honour of Marjorie and as a reference to the site where it was discovered. The term 'coelacanth' itself comes from a Greek word that means "hollow dorsal spine". The dorsal cartilage of the coelacanth, called a notochord, is in fact hollow and full of liquid.
It was once thought that this species represented a missing link between fish and terrestrial animals, due to the similarities between the skeletons, but this interpretation is no longer accepted today, even if coelacanths are clearly linked to the ancestors of terrestrial vertebrae. Since 1938, several hundred specimens have been caught and live specimens have even been observed, as shown in the video below. Another species of coelacanth was discovered in Indonesia in 1998.