The lineage of the coelacanth, an example of a "living fossil," was thought to have died out million of years ago. The coelacanth belongs to a group called lobe-finned fishes which were very common back in the Devonian, and its relatives was said to have evolved into the four limbs of the tetrapods, which include us mammals.
In the 1930s, African fishermen caught the lobe-finned fish and since then a stable population has been found near the Cormoros, a set of island in between Madagascar and the African coast.
A steady stream of the fish has been discovered along the African coast and initial genetic testing indicated that these were similar to the ones found the Cormoros. Thus, it was thought that the fishes simply drifted to Africa.
Further sightings, however, came about over thousands of kilometers, ranging from Kenya south to South Africa. This prompted a group of researchers to revisit the genetic data by sequencing the entire mitochondrial genome for 23 of the fish.
The researchers found out that contrary to their initial findings, the coelacanths off Kenya, Tanzania and Mozambique contained some sequences that were unique to the population. Unlike the coelacanths in Cormoros, the frequency of many alleles were also very different in the variety found in the African coast.
Genetic distance estimates among these populations are very broad, with speciation ranging from 5-30 million years. Still, even the low-end estimates suggest that the African coastal populations split off from the Cormoros group over 200,000 years ago.
The living fossil has successfully colonized the African coast, however, the area it has colonized is now subject to overfishing, which puts this new population at risk.
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