(.) – The coelacanth – an astonishing fish that was thought to have gone extinct alongside the dinosaurs 66 million years in the past, earlier than being unexpectedly discovered alive in 1938 off the east coast of South Africa – is providing new surprises.
Scientists stated in a new examine that these massive, nocturnal inhabitants of the deep sea have a life expectancy about 5 instances larger than beforehand believed – as much as about a century – and that females carry their younger for 5 years, the longest gestation interval identified in any animal.
Specializing in one of many two residing species of coelacanth, the scientists additionally decided that it develops and grows at one of many slowest charges of any fish and that it doesn’t attain sexual maturity till round 55 years of age.
The researchers used the annual development rings deposited on the fish’s scales to find out the age of the coelacanths, “similar to whenever you learn tree rings,” stated marine biologist Kélig Mahé of the French oceanographic establishment IFREMER and creator. predominant examine revealed this week within the journal Present Biology.
Coelacanths appeared in the course of the Devonian Interval, about 400 million years in the past, about 170 million years earlier than the dinosaurs. Primarily based on the historical past of the fossils, they have been thought to have disappeared in the course of the mass extinction that worn out about three-quarters of Earth’s species after an asteroid hit on the finish of the Cretaceous.
After being discovered alive, the coelacanth was listed as a “residing fossil,” a description now averted by scientists.
“By definition, a fossil is lifeless, and coelacanths have developed a lot because the Devonian,” stated biologist and examine co-author Marc Herbin of the Nationwide Museum of Pure Historical past in Paris.
The fins of the coelacanth are lobe-shaped, which differs structurally from different fish. These fish are believed to have paved the way in which for limb development within the evolution of the primary land vertebrates.
Coelacanths stay in ocean depths of as much as 800 meters. Throughout daylight they keep in volcanic caves alone or in small teams. The females are often bigger than the males, reaching about two meters and weighing about 110 kilos.
Earlier analysis had instructed that their life expectancy was round 20 years, with one of many quickest physique growths amongst fish. Nevertheless, it turned out that this was primarily based on misreadings made many years in the past with different sorts of rings deposited on the scales.
“After re-evaluating the life historical past of the coelacanth primarily based on our new age estimate, it seems to be one of many slowest – if not the slowest – of all fish,” stated Bruno Ernande, IFREMER marine evolutionary ecologist and examine co-author. “A centennial life expectancy is one thing.”
The Greenland shark, a massive predator of the deep ocean, is taken into account the longest-lived vertebrate on Earth, with a life expectancy of about 400 years.