The Coelacanth, Living Fossil of the Sea | Deep Sea Wonders
Once known only from fossils, the coelacanth was thought to have gone extinct around 65 million years ago in the late cretaceous, during the great extinction that wiped out the dinosaurs. Fossils of these creatures dated from 80 to 360 million years ago, and yet in 1938, one was found off the coast of South Africa alive. A fish almost entirely unchanged since the days of dinosaurs.
This discovery therefore represents one of the most significant natural history discoveries of recent times.
Living at depths of around 200 metres, down in the Twilight Zone of the ocean, they are found around the steep rocky slopes of volcanic islands, venturing forth from their lava-rock caves at night to feed; being passive drift-feeders, they move slow and feed on cephalopods and smaller fish.
Believed by many to have no living relatives, the Coelacanth is a truly unique species. They are the only living vertebrates with a jointed skull, that swings upward to greatly increase the gape of the mouth. Their limb-like pectoral fins are also unique, as they are internally supported by bone, a feature not found in many other fish. They use them in a paddle-like fashion, as if they are walking through the water column.
These unusual features have led to the coelacanth’s evolutionary history becoming a matter of controversy; but most experts argue it is an early ancestor of modern day bony fish, with lungfishes being its closest relative.
With fins so closely resembling limbs, coelacanths demonstrate the evolutionary pathway that saw life animal begin to dominate land; the alternating movement of the coelacanth fins resembles the foreleg and hind-leg movement of land-dwelling tetrapods.
The sight of these 2 metre long, 200 pound living fossils drifting in the deep is an ominous sight indeed. With only two known coelacanth populations in the world, both having been isolated for millions of years, their low numbers have led to a classification of critically endangered. Only a very small number of specimens have ever been observed, and without careful management of human activities, this species could be lost forever, after having survived unchanged for millions of years.
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Footage used:
• Coelacanth Dive, KZN (...
• Finding the Coelacanth...
• Diving With Coelacanths
• Fish that outlived din...
• A Fish Lost in Time: t...
• The African Lungfish |...
Music used: Still - Ross Bugden
• Beautiful and Relaxing...
Interesting information on the Coelecanth:
animals.howstuffworks.com/end...
evolution.berkeley.edu/evolib...
ocean.si.edu/ocean-life/fish/...
oceana.org/marine-life/ocean-...