By Stephen Beech
A pair of 430 million-year-old mollusk fossils have been named “Punk” and “Emo” by scientists.
Researchers say the newly discovered artifacts show that early lifeforms were “more complex and adaptable” than previously known.
They explained that spiky Punk resemble worm-like mollusks with long spines, but it also has a broad foot and gills like chitons.
Emo, similarly worm-like with a long body and spines, also features shells and a compressed body similar to chitons.
Mollusks are one of life’s most diverse animal groups and analysis of the newly discovered fossils is challenging long-held views on their early origins.
The fossils, dating from the Silurian period, were retrieved in Herefordshire and shed light on the mollusks’ complex evolutionary history and how they moved.
Scientists say the discovery challenges the longstanding view that early mollusks from the group known as Aculifera were basic and primitive.
Instead, the “rebellious” fossils – given the scientific names Punk ferox and Emo vorticaudum – show that early mollusks had some “unique” features and were, in fact, quite complex and adaptable in their forms and habitats.
Researchers drew their conclusions by recreating the fossils in 3D using advanced imaging techniques, including X-ray scanning.
They found that Emo and Punk displayed a wider variety of forms and movement strategies than researchers knew existed in early mollusks.
The study, published in the journal Nature, was led by Dr. Mark Sutton, from the Department of Earth Science and Engineering at Imperial College London.
Dr. Sutton said: “Mollusks are one of the largest and most diverse animal groups on Earth.
“However, early Aculiferan mollusks are much less well-known than some of their relatives.
“We have limited information about this group, and for a very long time, we assumed they were rather basic, simple and primitive.
“Retrieving fossils that are so exceptionally well preserved and reveal details of the soft tissues is extremely rare.
“We have been able to create ‘virtual fossils’ – 3D digital models – providing us with a gold mine of information and helping us understand that the branch of molluscan evolution containing Emo and Punk was much more evolutionarily rich and diverse than we thought; as much as other mollusk groups.”
Dr. Sutton worked on the project with researchers from Oxford University, the University of Leicester, Yale University, plus the Senckenberg Research Institute and Natural History Museum in Germany,
The team used two different methods to get a clear picture of the fossils, inside and out.
They used X-ray scanning to get a detailed look at the internal structures without causing any external damage.
The researchers then carefully ground the fossils down in very thin layers, taking photos at each step to create a 3D image of the external features.
They found both fossils had smooth undersides, suggesting that they lived on the sea floor, and they both possessed some unique features and unconventional movement methods.
Dr. Sutton said the Emo fossil is preserved in a folded posture, suggesting that it moved like an inchworm, using its spines to grip and push forward.
How Punk was able to move remains unclear to researchers, but they found it had a ridge-like foot, unlike any of today’s mollusks.
Dr. Sutton added: “The names Punk and Emo were actually our initial pet names for these ancient mollusks, inspired by some of their unique features and individuality.
“Punk in particular, with its spiky appearance, clearly resembles a rebellious punk rocker – and we thought Emo complemented it well.”
