The Coelacanth; A Living Fossil Back From Extinction

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The fish Coelacanth is an ancient living fossil which changed the way, we viewed evolution. Charles Darwin coined the term living fossil. This term is used to describe animals that have remained the same, or have barely changed over a long period of time. He theorized that some animals, wouldn’t have felt the pressure to evolve. He even went further and stated the best place to find one, would be in the oceans. The Coelacanth is the most famous and associated with the term living fossil.

Not only is it a living fossil but it was thought to be extinct. Lazarus taxon is when an animal, is thought to be extinct but is later re-discovered. This fish was thought to be extinct for 65 million years, around the same time as the dinosaurs. In 1936 the Coelacanth was re-discovered in the south coast of Africa and a second species was also discovered in Indonesia 1998. This fish can give us a look into the past as we know there was a wider range of around 90 species, millions of years ago.

This fish has barely evolved, from when it changed into its current form, around 400 million years ago. This is unusual but it doesn't end there. Coelacanth has a unique organ in the snout called rostral organ. Experiments have shown it’s a low electro-detector, which allows it to find its prey in the dark. Its skull is divided into two sections by the intracranial joint. The role of the intracranial joint is unclear but has long been associated with suction feeding. In the Coelacanth case, it is thought to increase its biting force. Both of these traits are no longer present in any other vertebrates.

This fish became even more famous, when it was thought to be the missing link to our ancestors. An accepted theory is our ancestors were fish, that began walking on land and scientist have been looking for this missing link. Coelacanth has fins that are long and bony, not at all much different from our limbs. They can rotate up to 180 degrees and they move much like arms and legs do. It was later disproved; as they weren’t used for walking on the seabed so the search continues.

We still don’t know much about this fish, like why it gives birth to living fish and doesn’t lay eggs? How they breed? Where they give birth? Where do the young go and why they don’t live with the adults? We don’t know there life expectancy or why it has both shark and fish traits? With so little left of the coelacanth race maybe it’s best we don’t. Well at least until we can capture one and keep it alive comfortably, as each one in captivity dies soon afterwards.
I think this shows how little we know about our vast oceans and what else could be down there.

Source
http://vertebrates.si.edu/fishes/coelacanth/coelacanth_wider.html