In December 1938, Marjorie Courtenay-Latimer, curator at the
East London Museum in South Africa, received an unusual call. A local trawler
had netted a large, pale mauve-blue fish—nearly five feet long—in the Indian
Ocean off the South African coast. Intrigued by its strange appearance and
unable to identify it using any known references, Courtenay-Latimer preserved
the specimen and reached out to her friend and ichthyologist, Professor J.L.B.
Smith of Rhodes University.
When Smith finally examined the specimen, though it had
already been taxidermied, he instantly recognized the fish as a coelacanth—a
species believed to have gone extinct 65 million years ago, alongside
the dinosaurs. The fish was later named Latimeria in honor of
Courtenay-Latimer’s role in its discovery, and it remains one of the most
remarkable finds in modern biology.
The Coelacanth: More Than Just an
Ancient Fish
The coelacanth isn’t just a rare or old fish—it represents
an extraordinary evolutionary bridge. Unlike common ray-finned fish, the
coelacanth belongs to a group called lobe-finned fish, which are more
closely related to lungfish, amphibians, reptiles, birds, and mammals
than to most modern-day fish. Its anatomy offers vital clues to the early
transition of life from water to land.
Coelacanths were once thought to have vanished during the
Cretaceous extinction, but today, only two known species remain, making
them the most endangered order of animals on Earth.
Unique Features That Fascinate
Scientists
- Lobed
fins for movement: These paired fins resemble limbs
and move in an alternating rhythm, much like a trotting horse. Some
scientists believe they may once have enabled the fish to “walk” along the
ocean floor.
- Hinged
skull: A rare joint in the skull allows the coelacanth to
open its mouth wider, helping it consume large prey.
- Thick
scales: Covered with cosmoid scales,
which were previously thought to exist only in extinct species.
- Notochord:
Instead of a vertebral column, coelacanths possess a gelatinous notochord,
a primitive structure that supports the body.
- Slow
evolution: Coelacanths have changed little
over millions of years, earning them the nickname “living fossils.”
Where Are Coelacanths Found Today?
Since that first discovery in 1938, around 200
coelacanths have been documented, most of them off the coast of the Comoro
Islands between Mozambique and Madagascar. Another distinct population,
with brown coloring, has been found in Indonesian waters. These deep-sea
dwellers can grow up to 6.5 feet (2 meters) long, weigh around 175
pounds (80 kilograms), and live for 80 to 100 years.
Key Takeaways for the Curious Reader
- The
coelacanth’s discovery reshaped our understanding of vertebrate evolution.
- It
provides a direct connection between aquatic life and the first
land-dwelling animals.
- Its
unique anatomy and long evolutionary history make it one of nature’s most
captivating survivors.
- Though
rare, the coelacanth continues to intrigue scientists as a living window
into Earth's distant biological past.
- Its
survival raises hope—and questions—about other "extinct" species
that may still be hiding in the depths.
The story of the coelacanth reminds us that science is
always evolving—and that sometimes, history swims right up from the depths when
we least expect it.
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A life-sized replica of the Indonesian coelacanth (Latimeria menadoensis) is showcased at the Tokyo Sea Life Park, offering visitors a rare glimpse of this ancient and elusive deep-sea species. |
