The largest fossil of an ancient deep-sea fish once thought to be extinct was recently found—entirely by mistake.
Paleontologists in the UK were given what they were told was a pterodactyl bone, but after a closer inspection, the team realized it wasn't one bone.
The specimen was identified as a thin bone of plates belonging to a coelacanth, a fish that came on the scene 200 million years before the first dinosaurs and is still swimming around today.
One of the strangest aspects of the coelacanth is that it has a vestigial lung, possibly from a time when its ancestors crawled on land.
The researchers determined the fossil was actually a coelacanth's spindly lung bones, which lived 66 million years ago.
Scientists long believed the coelacanth died out eons ago, until a living one was spotted in the waters off South Africa in the 1930s.
David Martill, a paleontologist at the University of Portsmouth had been asked to identify a large bone bought by a private collector, who suspected it might be part of a pterodactyls' skull.
Martill quickly determined the fossil was actually composed of many thin bony plates 'arranged like a barrel, but with the staves going round instead of from top to bottom,' he explained.
'Only one animal has such a structure and that is the coelacanth,' he said. 'We'd found a bony lung of this remarkable and bizarre looking fish.'
The collector was disappointed he didn't have a pterodactyl on his hands, but Martill and his colleagues were 'thrilled' by the discovery.
The fossil had been uncovered in phosphate deposits of Morocco, the first coelacanth ever found there.
It was found next to a pterodactyl, which dates it to the Cretaceous era—about 66 million years ago—and explained the collector's misidentification.
Marine biologists only discovered the elusive deep-sea fish had an obsolete lung lurking in its abdomen in 2015.
Millions of years ago, the coelacanth's ancestors likely used it to breath.
That could explain how it survived the extinction event 66 million years ago that wiped all non-avian dinosaurs and most other life from Earth, as well as those coelacanths inhabiting shallow waters.
This lung belonged to an 'absolutely massive' coelacanth, Martill said, possibly 16 feet or longer.
In comparison, the great white shark is about 15 feet long—and modern-day coelacanths only grow to about six-and-a-half feet.
'This particular fish was enormous—quite a bit longer than the length of a stand-up paddleboard and likely the largest coelacanth ever discovered,' Martill said.
The fossil had been embedded in phosphate and plaster and coated in lacquer, turning it brown.
Martill's team had to cut the remain of the lung off the larger slab and remove the lacquer using dental tools and fine brushes.
The bony lung has been sent back to Morocco to be added to the collections at Casablanca's Hassan II University.
The coelacanth first appeared 400 million years ago—200 million years before the first dinosaurs—and survived the extinction event that killed the dinosaurs.
It had long been believed to have died out toward the end of the Mesozoic era, but in 1938 a living coelacanth was found off the coast of South Africa.
Since then, a few other individual fish have been found, as well as members of a related species off the coast of Indonesia.
But the coelacanth, which is considered endangered, is a truly unique creature in many ways.
For example, it has 'lobe-shaped' fins that move in an alternating pattern, similar to a four-limbed land animal.
This movement has led experts to speculate it may have been a member of a group of fish that first crawled onto land to evolve into animals with legs.
The grey-brown fish can weigh as much as 200 pounds and live up to 60 years.
It has a hollow, liquid-filled spine, enamel-capped teeth, and a hinged jaw that allows it to open its mouth wide to swallow large prey.
Little is known about how the fish lives, what it eats, how it reproduces, or how many of them are left.
Until recently the coelacanth was known as the 'living fossil,' having changed little in hundreds of millions of years. Scientists now believe it has undergone a more substantial evolution than previously thought.
This article has been adapted from its original source.
© Associated Newspapers Ltd.