Mark Sutton, a paleontologist at Imperial College London, is no punk.
“I'm more of an ethnic, country guy,” he said.
But when Sutton pieced together 3D renderings of the tiny mollusk fossils, he was struck by the spikes that covered its insect-like body. “It's kind of like the classic punk hairstyle, the way it sticks out,” he thought. He called the fossil “punk.” Later, he discovered a similar fossil with downward-pointing spines, reminiscent of long, side-swept “emo” bangs. He named the specimen after the emotional alternative rock genre.
On Wednesday, Sutton and his colleagues published a paper in the journal Nature, officially naming the creatures as the species Punk Ferox and Emo Vorticaudum. As their name suggests, these molluscs are the subject of some kind of turmoil (if not outright “British anarchy”) over scientists' understanding of the origins of one of the largest animal groups on Earth. also) is behind.
In terms of the number of species, molluscs are second only to arthropods (a group that includes insects, spiders, and crustaceans). The best-known half of the mollusk family tree, Conchifera, includes animals such as snails, bivalves, and octopuses. “The other half is this weird group of spiny things,” Dr. Sutton said. Some of the animals in this category, the aculifera, resemble armored nudibranchs, while others are “strange molluscs of unknown identity,” he said.
The predecessors of today's molluscs, punks and emos lived on the dark ocean floor surrounded by gardens of sponges about 200 million years before the first dinosaurs appeared on land. Their ancient seabed is now a fossilized site on the border of England and Wales.
The site is littered with rounded boulders that “look a little like potatoes”, Dr Sutton said. “And when you crack it open, some of them have these fossils in them. But the problem is, they don't look very similar at first.”
Although tubercles can preserve an animal's entire body in 3D, the cross-sections seen when the tuberosity is split can be difficult to interpret “because the complete anatomy is not visible,” Dr. Sutton said.
Paleontologists can use CT scans to see what parts of fossils are still hidden within rocks. It essentially takes thousands of X-rays of a fossil and stitches those X-ray slices together into a single digital 3D image. However, in these nodules, the densities of the fossilized organisms and the surrounding rock are so similar that they cannot be easily distinguished using X-rays. Instead, Dr. Sutton essentially recreated this slicing and imaging process by hand.
“We scrape off a slice at a time, photograph it, and repeat every 20 microns or so, basically destroying the fossil, but digitizing it as we go along,” Sutton said. At the end of the process, the original fossil blob becomes a “sad-looking pile of dust,” but when thousands of images are painstakingly combined with digital technology, the result is a stunning picture of a fossilized animal. .
A hot topic for punk and emo, Spike stands out from other fossils in the molluscan family Aculiferanidae. “We don't know much about acriferan, and it's unusual to suddenly find out there are two,” Dr. Sutton said.
Stewart Eadie, curator of bivalve fossils at the Smithsonian's National Museum of Natural History, said the bizarre appearances of punks and emos challenge long-held understandings of how molluscs evolved. Previously, scientists thought that a group of mollusks, including snails, shellfish and cephalopods, had “seen all the evolutionary activity,” said Dr. Eadie, who was not involved in the new discovery. “And the other major group, the aculifera, were much less adventurous.” But punk and emo “go against that trend,” he said.
New altonic aculifera reveal the hidden diversity of their group in the distant past and raise questions about why their descendants make up such a small part of the molluscan class today . “This gives us an almost unprecedented window into the kinds of organisms that actually existed when molluscs started,” Sutton said. “This is a strange, unexpected, and very revealing look at what was going on in the early history of one of our most important animal groups.”
