In A Nutshell
A species of fish thought to be extinct since the time of dinosaurs, the coelacanth was rediscovered in 1938 and is still around today—a living fossil that may even hold clues to the development of mammals.
The Whole Bushel
In 1938, an anonymous South African fisherman pulled something out of his net that looked like a monster. At over 100 pounds and 1.5 meters (five feet), it would come to be regarded as one of the most important zoological finds of all time—it was determined to be a coelacanth, which was a known species. Known, that is, to have been extinct since the Cretaceous Period, about 65 million years ago.
They are, of course, exceedingly rare and difficult to spot—mostly due to the fact that they’re sensitive to light and prefer to hang out at a depth of 90 to 180 meters (300 to 600 ft), though they can go as deep as 700 meters (2,300 ft). And while not exactly “frozen in time”—DNA changes have accrued over the millennia—they are practically identical to the fish that shared the oceans with plesiosaurs.
Incredibly, the coelacanth is a “lobe-finned” fish of the type that evolved into amphibians and then mammals. Like lungfish, they are more closely related to humans and mammals than they are to “ray-finned” fish such as trout, and their genome is expected to yield significant information about the development of tetrapods—the evolutionary line that produced nearly all land-dwelling animals, including humans.