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Tridentinosaurus antiquus: “It all makes sense now”

Photo: Valentina Rossi

Fossils help scientists understand times from which there are otherwise few remains. This also applies to an approximately 280 million year old reptile of the species Tridentinosaurus antiquus, which is currently considered one of the oldest fossils with preserved soft parts in the Italian Alps. But the piece can only contribute to a limited extent to a greater understanding of the early evolution of animals, as it now turns out.

The fossil from the Permian Age is probably at least partly a fake, experts led by Valentina Rossi from University College Cork in Ireland report in the journal “Palaeontology”. Essentially black paint can be seen on a lizard-shaped rock surface.

Disappointment under black paint

The outlines of Tridentinosaurus antiquus stand out darkly against the lighter Alpine rock. Experts initially interpreted this primarily as an indication of preserved soft tissue, according to a statement about the study. This refers to all tissues except bones, such as skin, muscles, fat or blood vessels.

Rossi and colleagues now examined the remains more closely, for example with microscopes. Accordingly, the texture and composition of the material do not match real fossilized soft tissues.

Preliminary analysis using UV photography also revealed that the entire fossil was coated with a material. This in itself is not unusual: it is said that coating fossils with varnishes and paints was common in the past. Even today it is still used occasionally, for example to preserve an exhibit.

The team therefore initially hoped to find the original soft parts still in good condition beneath the coating. But she was disappointed.

Decade-long mystery

The fossil was found in 1931, more than 90 years ago. The specialist team attributes the fact that the fake went unnoticed for so long to the fact that the reptile's supposedly fossilized skin was described in articles and books but was never examined in detail.

“The strange state of preservation of Tridentinosaurus has puzzled experts for decades,” said co-author Evelyn Kustatscher, according to the statement. »It all makes sense now. What was described as charred skin is just paint.”

But the team doesn't have all bad news: According to the analyses, the bones of the reptile's hind legs, especially the thigh bones, are real, albeit poorly preserved. The research also revealed small bony plates, called osteoderms, on the animal's back.