Famous fossil is really just paint, rocks and a couple of bones, researchers say

A 280 million-year-old fossil thought to be a well-preserved specimen of an ancient reptile is largely a forgery, according to new research.

The fossil, initially discovered in the Italian Alps in 1931, has the scientific name Tridentinosaurus antiquus. Scientists thought the dark, deep outline of the lizardlike body encased in rock was skin and soft tissue, and they considered the fossil to be a puzzle piece for understanding early reptile evolution.

The fossil appeared in book and article citations over the decades, but no one ever studied it in detail. Housed in the collections at the University of Padua’s Museum of Nature and Humankind in Italy, the relic raised many questions about the exact nature of the creature it was in life when additional, similar specimens couldn’t be found.

A new, detailed analysis has revealed that the dark color of the fossil isn’t preserved genetic material — it’s just black paint covering a couple of bones and carved rock. The researchers behind the study reported their findings February 15 in the journal Paleontology.

“The body outline of this fossil specimen has the same colour of genuine fossilised soft tissues of plants and also animals,” said lead study author Dr. Valentina Rossi, postdoctoral researcher in paleobiology at University College Cork in Ireland, in an email. “So, without the use of diagnostic techniques, it was impossible to identify the dark colored material properly.”

The revelation highlights the fresh knowledge that could be reaped from reexamining old and previously studied fossil specimens in museum collections using the latest technological methods.

Unveiling a forgery

Reptiles first appeared between the Carboniferous and Permian eras, about 310 million to 320 million years ago. But understanding the evolution of these scaly vertebrates depends on what paleontologists unearth in the fossil record, and the diversity of the earliest reptilian animals is still a knowledge gap researchers are trying to fill.

Even rarer among ancient finds are fossils that contain soft tissue, which has the potential to harbor crucial biological information like DNA.

When the specimen was discovered, researchers thought the fossil might provide a rare glimpse into reptilian evolution.

“The fossil was believed to be unique because there were no other examples from the same geographical area and geological period of that preservation in a fossil vertebrate at the time,” Rossi said.

But the color of the supposed skin was similar to what had been observed in fossil plants found in similar rocks, Rossi said.

There were oddities about the find, such as a general lack of visible bones, including the skull bones, despite the fact that the body didn’t appear completely flat. So the initial assessment was that the specimen was essentially a mummy of an ancient reptile.

“A plausible explanation was that the bones were hidden below the layer of skin and thus not visible,” Rossi said. “There are few examples of dinosaurs mummies, where pretty much like human mummies, the bones are still wrapped inside the skin which is preserved in 3D.”

Intrigued by the growing uncertainty surrounding the fossil, Rossi and her colleagues began their study in 2021 by examining it with ultraviolet photography. The analysis revealed that the specimen was covered in a thick coating, Rossi said.

“Coating fossils with varnish is an ancient method of preservation because, in the past, there were no other suitable methods to protect fossils from natural decay,” said study coauthor Mariagabriella Fornasiero, curator of paleontology at the Museum of Nature and Humankind, in a statement.

Hoping to find biological information about the fossil beneath the coating, the team used powerful microscopes to analyze the samples of the remains across different wavelengths of light.

Instead, the researchers determined that the body outline was carved in the rock and painted with “animal charcoal,” a commercial pigment used about 100 years ago that was made by burning animal bones. The carving also explained why the specimen appeared to retain such a lifelike shape, rather than appearing flatter like a genuine fossil.

“The answer to all our questions was right in front of us, we had to study this fossil specimen in detail to reveal its secrets — even those that perhaps we did not want to know,” Rossi said.

The result was unexpected, but it explains why the fossil baffled researchers for decades. The latest research confirms it “is not the oldest mummy in the world,” said study coauthor Evelyn Kustatscher, curator of paleontology at the South Tyrol Nature Museum in Bolzano, Italy, and coordinator of the research project, in a statement.

Old secrets and new questions

Intriguingly, there are actual bones within the fossil. The hind limbs, although in poor condition, are real, and there are also traces of osteoderms, or scalelike structures. Now, the researchers are trying to determine the exact age of the bones and what animal they belonged to. The team is also studying the rock, which may also preserve insightful details from 280 million years ago.

It’s not the first time a fossil forgery has been uncovered, but Rossi said this particular style of forgery is unusual.

“The only fossil that I am aware of that was painted over rock is a fossilised crayfish which was made to look like a giant spider,” Rossi said. “In this particular case, however, the type of paint wasn’t identified, but I bet is a carbon-based one similar to what we found on our fossil.”

Given the lack of records to accompany the fossil, including a description of what exactly was found in 1931, Rossi and her team can’t be entirely sure that the forgery was done on purpose.

“We believe that, since some of the bones are visible, someone tried to expose more of the skeleton, by excavating more or less where someone would expect to find the rest of the animal,” Rossi said. “The lack of proper tools for preparing the hard rock did not help and the application of the paint in the end was perhaps a way to embellish the final work. Unfortunately, whether all of this was intentional or not, it did mislead many experts in interpreting this fossil as exceptionally preserved.”

Using advanced techniques to study fossils can reveal their true nature, Rossi said.

“It is of fundamental importance that research uses new methods to take a closer look at finds that have already been examined,” said study coauthor Fabrizio Nestola, professor of mineralogy and president of the University Center for Museums at the University of Padua, in a statement.

“The Tridentinosaurus is an example of how science can reveal old secrets — and how new questions can arise from them,” Nestola added. “It will then be the task of our museum to process the newly gained knowledge and bring it to the public in order to lead a scientific and cultural debate.”