"Living fossil" populating the coast of Africa
The coelacanth is a textbook example of what’s sometimes termed a "living fossil." It belongs to a group called lobe-finned fishes, which were very common back in the Devonian. In its relatives, the long, lobed fins evolved into the four limbs of the tetrapods, which include us mammals. The lineage was thought to have died out millions of years ago, until African fishermen pulled up a coelacanth in the 1930s. Since then, a stable population has been found near the Cormoros, a set of islands that lie in between Madagascar and the African coast.
Since that time, a steady stream of the fish has been discovered along the African coast. Initial genetic testing indicated that these animals were very similar to the ones found in the Cormoros; this suggested that they had simply drifted to Africa on one of the prevailing currents in the area. But over time, sightings piled up over thousands of kilometers, ranging from Kenya south to South Africa. So a group of researchers went back and revisited the genetic data by sequencing the entire mitochondrial genome for 23 of the fish.