In 1938, Marjorie Courtenay-Latimer examined the body of a fish recently caught by some South African fishermen. She knew immediately that she was looking at something extraordinary. Courtenay-Latimer regularly gathered interesting specimens to display at the natural history museum where she worked. But she had never seen anything like this five-foot, steel-blue fish with armor-like scales and thick, limb-like fins. On a hunch, she took the fish back to the museum and tried to contact J. L. B. Smith, an acquaintance who was an expert in the study of fish.
Smith, however, was out of town and could not be reached. So, Courtenay-Latimer wrote him a letter and included a sketch of the strange fish. When Smith eventually got the letter and saw the drawing, he was shocked. It looked like a coelacanth (pronounced SEE-la-kanth)—a fish believed to have been extinct for sixty-six million years. How was that possible? When Smith finally arrived to inspect the mounted remains of the fish, it was confirmed. The specimen was an exact match of the fossilized imprints of coelacanths that had been collected and studied for decades.
The discovery of a recently living coelacanth sent shock waves through the scientific community. Coelacanths were believed to be a long-gone species that may have represented a step in the evolution of sea creatures into four-limbed land animals. News of the discovery made front-page headlines around the world. People were fascinated by this strange "living fossil" with leg-like fins.
Since that 1938 discovery, other living coelacanths have been found. After Smith offered a reward to anyone who could provide him with another specimen, a second coelacanth was finally located in 1952. More have been captured since, but not many. These elusive fish live deep in the ocean, hundreds of feet down in the murky depths known as the twilight zone. Eventually, in the 1990s, a second distinct species of coelacanth was discovered. Divers with special equipment and scientists in underwater craft have been able to observe both species. The first species lives mainly around the Comoros Islands off the east coast of Africa. The other lives six thousand miles away, in Indonesian waters.
Despite the challenges of studying coelacanths, scientists have managed to discover a number of remarkable features about these fish. Unlike almost all known species of living fish, coelacanths do not have a true backbone. Instead, they have a primitive, oil-filled tube called a notochord. They also have a unique hinged skull. The top of the skull swings up, allowing coelacanths to open their mouths wide and scoop up fish and squid while drifting along the ocean floor. In addition, an unusual gel-filled organ in their snouts helps them locate prey by detecting the weak electrical fields produced by living things in water. Perhaps most noticeable are the two pairs of bony, leg-like fins that stick out from the sides of coelacanths' bodies. These fins move in an alternating pattern that resembles a horse's trot, hinting at a connection with land animals.
Scientists believe that coelacanths can live about sixty years. These unusual fish have no known predators, protected as they are by their armor of thick scales. Even so, coelacanths are listed as endangered. Their biggest known threat is from people who snare them accidentally in fishing nets or hunt them as specimens for museums. But coelacanths have already surprised us with their amazing ability to survive. They have been around for hundreds of millions of years and returned from a presumed state of extinction. Who knows how many of these living fossils remain hidden in the depths of the sea?
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