'Living fossil' fish surprises scientists with 100-year lifespan
The coelacanth — a wondrous fish that was thought to have gone extinct along with the dinosaurs 66 million years ago before unexpectedly being found alive and well in 1938 off South Africa's east coast — is offering up even more surprises.
Scientists said a new study of these large and nocturnal deep-sea denizens shows that they boast a lifespan about five times longer than previously believed — roughly a century — and that females carry their young for five years, the longest-known gestation period of any animal.
Focusing on one of the two living species of coelacanth, the scientists also determined that it develops and grows at among the slowest pace of any fish and does not reach sexual maturity until about age 55.
The researchers used annual growth rings deposited on the fish's scales to determine the age of individual coelacanths — "just as one reads tree rings," said marine biologist Kélig Mahé of the French oceanographic institution IFREMER, lead author of the study published this week in the journal Current Biology.
Coelacanths first appeared during the Devonian Period roughly 400 million years ago, about 170 million years before the dinosaurs. Based on the fossil record, they were thought to have vanished during the mass extinction that wiped out about three-quarters of Earth's species following an asteroid strike at the end of the Cretaceous Period.
