Unlike these fish, which are actually extinct, the coelacanth is a type of fish that was believed to be extinct. However, an unexpected twentieth- century rediscovery of living coelacanths has brought about a reassessment of the status of the prehistoric sea creature that was believed to have long since disappeared from the Earth. From fossil remains of the coelacanth, paleontologists have determined that the coelacanth was in existence around 350 million years ago, during the Paleozoic Era, more than 100 million years before the first dinosaurs arrived on the Earth. The most recent fossilized coelacanths date from around 70 million years ago, near the end of the age of dinosaurs. Because no fossilized remnants of coelacanth was believed to have died out around the same time as the dinosaurs.
The prehistoric coelacanth studied by paleontologists had distinctive characteristics that differentiated it from other fish. It was named for its hollow spine and was known to have been a powerful carnivore because of its many sharp teeth and a special joint in the skull that allowed the ferocious teeth to move in coordination with the lower jaw. It also had a pair of fins with unusual bony and muscular development that allowed the coelacanth to dart around the ocean floor. These fins also enable the coelacanth to search out prey trying to hide on the ocean bottom.
In 1938, a living specimen of the coelacanth was discovered in the catch of a fishing boat off the coast of South Africa, and since then numerous other examples of the coelacanth have been found in the waters of the Indian Ocean. This modern version of the coelacanth is not exactly the same as its prehistoric cousin. Today's coelacanth is larger than its prehistoric relative, measuring up to six feet in length and weighing up to 150 pounds. However, the modern version of the coelacanth still possesses the characteristic hollow spine and distinctive fins with their unusual bony and muscular structure.
It can be inferred from the passage that the first dinosaurs most likely appeared on Earth around
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