Mammals these days have hair, birds have feathers, and reptiles have neither.

But the relative nakedness of today’s reptiles may not have been the case 247 million years ago, when at least one reptile species appeared to be quite experimental with its embellishments.

That’s according to fossils of a creature that lived at the beginning of the Triassic period and sported a curious crest running down its spine.

The crest, while feather-like, pre-dates feathers by millions of years.

A new study published in Nature has described the crested reptile, which was dubbed Mirasaura grauvogeli.

Stephan Spiekman, study lead author and a researcher at the State Museum of Natural History in Stuttgart, Germany, said he was fascinated by the creature’s complex appendages — particularly since it didn’t belong to the group of animals that eventually grew feathers.

Dr Spiekman and his colleagues had 80 fossil specimens of the reptile. (Supplied: SMNS, Yannik Scheurer)

“Mirasaura was a type of reptile that was very different from dinosaurs and their close relatives,” Dr Spiekman said.

Stephen Poropat, a palaeontologist at Curtin University who wasn’t involved with the research, called the fossils an “extraordinary” find.

“If we saw it with modern eyes, as a living animal, it would be something totally unique,” he said.

The fossil treasure trove lying in wait

The Mirasaura fossils were discovered by French palaeontologist Louis Grauvogel in the 1930s in north-eastern France.

He found rocks containing small reptilian skeletons, alongside fan-like depressions made from plumes up to 15 centimetres long.

Professor Grauvogel thought the mysterious fans were fish fins or insect wings, and didn’t connect them to the reptilian skeletons found in the same fossils.

In 2019, decades after his death, Professor Grauvogel’s collection was acquired by the museum in nearby Stuttgart, and researchers realised that 80 of the fossils belonged to the same animal.

Out of 80 fossils, just two had Mirasaura’s entire body preserved. (Supplied: Stephan Spiekman)

The researchers named the creature Mirasaura grauvogeli, which means “Grauvogel’s wondrous reptile”.

But they couldn’t immediately tell what the mysterious crests on the creatures’ backs were made of.

“It was clear pretty quickly that these appendages were not feathers or hairs in the traditional sense,” Dr Spiekman said.

The team used a number of techniques, including powerful X-rays and electron microscopes, to reconstruct what the creature looked like and figure out the composition of the crests.

They discovered remnants of tiny cells called “melanosomes” preserved in the fossil crests, which make the colours in hair, skin and feathers.

Dr Spiekman said the crests would have been made from dead cells, like hair in modern mammals or feathers in modern birds. (Supplied: Stephan Spiekman)

The melanosomes were shaped similarly to those found in feathers, Dr Spiekman said.

“This could indicate that the tissue that they are composed of is quite similar to that of feathers.”

But the appendages were clearly different to feathers: they didn’t have any of the key branching features feathers develop as they grow.

“This shows that the structures grew in a largely different way than feathers,” Dr Spiekman said.

Anatomical analyses of the reptile’s skeleton also showed that it belonged to a different group of reptiles to the one that eventually became the dinosaurs.

Crest prompts evolutionary questions — and answers

John Long, a palaeontologist at Flinders University who wasn’t involved in the research, said that the existence of Mirasaura has profound implications for understanding how feathers and skin evolved.

“Prior to this discovery, it was thought that only birds and dinosaurs evolved feather-like structures, and mammals modified those feather-like structures to develop hair,” Professor Long said.

“This is a third group of animals yet discovered that actually have feather-like structures as part of their skin.”

It’s not clear whether Mirasaura could move its crest, or if it was stuck in one position. (Supplied: SMNS, Tobias Wilhelm)

Dr Poropat said the discovery helped explain another highly controversial fossil find from a similar time period, called Longisquama insignis.

The extinct Longisquama reptile, which was discovered more than 50 years ago, also had feather-like appendages, but its fossils weren’t preserved well enough to identify them properly.

This led to fierce debates about whether or not the Longisquama reptile had real feathers.

“The finding of Mirasaura demonstrates Longisquama’s structures are not feathers, because the Mirasaura reptile’s are very similar and they’re not feathers either,” Dr Poropat said.

“I’m quite relieved to see that Longisquama finally has a home.”

What was the crest used for?

The researchers believe the reptiles used the crest to communicate with each other.

“It seems most likely that it was used for signalling to other members of the same species, either to attract a mate, or to warn off a competitor, or both,” Dr Spiekman said.

Professor Long said that we can only speculate about the crest’s function, but he agreed that communication was a likely reason.

“Certainly today, visual signalling is incredibly important for birds and for many reptiles,” he said.

Because the animals only had one crest and it wasn’t supported by a bone structure, the researchers think it can’t have been used for flying or gliding. (Supplied: Rick Stikkelorum)

Dr Poropat pointed out the Mirasaura reptile lived a few million years after the catastrophic Permian mass extinction. This may have favoured the evolution of more bizarre behaviours and body structures because there was less competition.

“The animals that did survive that extinction event were basically free to experiment with all sorts of different modes of life.”

While the Mirasaura reptile isn’t a precursor to the dinosaurs, its existence suggests that other Triassic creatures could also have had strange features that haven’t survived fossilisation.

“Because soft tissue is so seldom preserved, we are getting an incomplete picture of the past almost inevitably,” Dr Poropat said.

” It is quite possible that we can’t just apply scaly skin to most Triassic reptiles or most Triassic mammal forerunners. “

A bizarre reptile once scurried through the Triassic treetops with an extravagant crest on its back, one made from neither scale, nor bone, nor feather.

The extinct creature’s 247-million-year-old fossils immediately stood out to paleontologists. The impressive appendage on its back looks like a frill of overlapping feathers at first glance, but it’s much older than the earliest fossilized feather, and there’s no branching to indicate a plume.

The elaborate structure also lacks bony spines, such as those seen in later dinosaurs, like Spinosaurus.

Related: ‘Beyond Doubt’: Proteins in Fossil From Actual Dinosaur, Claim Scientists

“This had to be something new,” Stuttgart State Museum of Natural History paleontologist Stephan Spiekman told ScienceAlert.

“Prior to our discovery, complex outgrowths from the skin were restricted to mammals and birds and their closest relatives, predominantly in the form of feathers and hair.

“We now have another, different type of complex appendage, in a very early reptile.”

Long before dinosaurs evolved plumage, it appears that some early reptiles were already putting together a genetic toolkit for complex appendages.

The dorsal crests discovered by Spiekman and his colleagues are “basically novel to science”, so they don’t yet have a name. In their study, the researchers essentially refer to them as skin outgrowths, but they aren’t actually similar to reptile skin.

Spiekman thinks the outgrowths may be made of keratin, similar to nails, hairs, scales, or claws. Confirming that suspicion will require further analysis.

Altogether, Spiekman and his colleagues studied more than 80 fossils of the outgrowths, recently donated to the State Museum of Natural History in Stuttgart, Germany.

The vast majority had lost their corresponding skeletons; only one of the fossils featured the bird-like skull of a small, ancient reptile.

The extinct animal has been named Mirasaura grauvogeli, the first part of which means ‘wonderous reptile’.

Technically, the species is a drepanosaur – a small, early reptile that lived in the trees, hunting insects with its velociraptor-like claws.

But its crest is the real stand-out feature.

“Mirasaura developed an alternative to feathers very early in Earth’s history, long before the dinosaurs, which we did not expect and which will stimulate discussion and research,” says reptile paleontologist Rainer Schoch, from the State Museum of Natural History in Stuttgart.

The exact function of the Mirasaura’s dorsal appendage is unknown, but based on the physics, it probably wasn’t used for flight or insulation. A role in visual communication, such as predator deterrence or intraspecies signaling, is more likely.

The best preserved Mirasaura fossils were found to contain traces of melanosomes, which are organelles within pigment cells.

Interestingly, their geometry is consistent with the melanosomes that color feathers, but not those found in reptile skin or mammal hair.

“Mirasaura really shows how surprising evolution can be, and how much we can still learn from palaeontology,” Spiekman told ScienceAlert.

“We already knew from genetics and developmental biology that much of the pathway to form feathers, hairs, and scales, is shared between mammals, reptiles, and birds. Now, with Mirasaura, we can say that such complex structures did indeed grow in other animals, too.”

Turns out, reptiles aren’t the scaly, simple animals we often paint them out to be. They deserve more credit.

The study was published in Nature.

Reconstruction and illustration of mirasaura in its natural forested environment, hunting insects. Photo: Gabriel Ugueto

Another feather in university’s cap

A significant breakthrough has been made which completely disrupts the view of the evolution of skin and feathers in reptiles.

An international team of researchers including palaeontologists at UCC have discovered a new species of fossil reptile from the Triassic period that had a large crest made of complex plume-like structures – long before modern-type feathers evolved.

The 247 million year old fossil, Mirasaura Grauvogeli from the Grès à Voltzia locality in northeastern France, had a bizarre showy plume of long outer layer structures. These share similarities with feathers, despite existing 70 million years before the oldest fossil feathers.

The research, published on Wednesday in the journal Nature, includes UCC palaeontologists Prof. Maria McNamara, Dr Valentina Rossi and Dr Tiffany Slater. The study was led by scientists Dr Stephan Spiekman and Prof. Dr Rainer Schoch from the State Museum of Natural History Stuttgart, Germany, along with an international team from Germany, Italy, France and the USA.

The UCC team analysed the fossil outer layer – or integumentary – structures using scanning electron microscopy and synchrotron X-ray analyses. The fossil tissue is rich in preserved melanosomes – cell organelles that contain melanin pigments – that are common in skin, hair, feathers and internal organs of fossil and modern vertebrate animals.

The UCC team discovered that the melanosomes in mirasaura are similar in shape to those in feathers, but not mammal hair or reptilian skin.

“We know that in modern animals, melanosome shape is closely linked to tissue type,” said Dr Valentina Rossi. “We can therefore be confident that the mirasaura structures share some common developmental features with feathers.”

Unlike feathers in modern birds, however, the mirasaura structures lack branching, showing instead a simple long, medial feature that superficially resembles the shaft of modern bird feathers.

“We were looking in the right time window, but we were shocked to find long integumentary structures in a completely different group of ancient reptiles,” says Prof. Maria McNamara, leader of the UCC team and coauthor of the study.

Co-author Dr Tiffany Slater said: “It’s amazing – this creature forces us back to the drawing board for when feather-like structures first evolved. Mirasaura reveals a deeper, more complex evolutionary story than we ever expected.”

“I’m stunned and flabbergasted,” says Steve Brusatte, a paleontologist at the University of Edinburgh who was not involved in the study. “It’s been a long time since I’ve been so blown away by a new fossil discovery.”

The finding, which was published Wednesday in Nature, also helps solve a decades-old paleontological mystery.

“There was always a distinction made between feathered dinosaurs and scaly reptiles,” says Stephan Spiekman, a paleontologist at the State Museum of Natural History in Stuttgart, Germany and an author on the paper. “And that’s too black and white of a story.”

A ‘miraculous reptile’

The specimens first came to light in May 1939, when private fossil collector Louis Grauvogel was prospecting quarries in the Triassic rocks of northeastern France. He found dozens of isolated structures he assumed to be fossilized fish fins, or insect wings, as well as the partial skeleton of a reptile. But when the Stuttgart State Museum of Natural History acquired his collection in 2019, Spiekman says, a museum researcher noticed faint ribs at the base of one of the fossilized structures. Carefully preparing away the rock, they found the preserved torso, neck and skull with the two-inch crest projecting out of the upper back. The structures and skeletons belonged to the same animal.

After studying the skeletal remains and over 80 specimens of isolated crests, the team chose the name Mirasaura grauvogeli, “Grauvogel’s miraculous reptile.” While the skeletons represent young animals, Spiekman says, the size of some of the isolated crests in the collection suggest adults could be well over a foot long.

A delicate, innocuous little fossil reptile known as Mirasaura grauvogeli – “Grauvogel’s wonder reptile” – is forcing a rethink about the evolution of skin and its appendages such as feathers and hair.

These newly discovered fossils, from the Middle Triassic (247 million years old) Grès à Voltzia site in northeast France, preserve evidence of some of the most astonishing soft-tissue features described to date in ancient reptiles. We are two of the authors of a new paper on these finds, published in Nature.

These fossils show that the tree dwelling Mirasaura had a large and startling crest along its back. The crest is formed by elongated appendages that are neither scales, feathers nor hair.

Until now, complex skin outgrowths such as feathers were thought to have evolved only much later – in birds, dinosaurs and pterosaurs. This probably occurred through a single origin in the common ancestor of these animals. In all other types of reptile, the only skin outgrowths present are scales.

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Mirasaura has overthrown this paradigm in sensational fashion. Compared with the size of its body, the long blades of its tall dorsal crest are enormous. Closer inspection reveals this crest comprised individual, overlapping appendages, each with a narrow central ridge and a lobed outline, similar to the shaft and form of feathers.

However, the fossil structures seem to lack the fine branching architecture that characterises most feathers in modern birds. What’s more, Mirasaura is not related to birds, dinosaurs or pterosaurs, but instead belongs to a very ancient group of reptiles, the drepanosauromorphs, that are known only from the Triassic.

Copyright: Stephan Spiekman , CC BY-NC-ND

The soft tissues of Mirasaura are preserved as a thin brown film, rich in fossil melanosomes – cell structures that contain the pigment melanin during life. Research by our team at University College Cork and others has revealed widespread preservation of fossilised melanosomes in ancient vertebrates. These pigment granules can actually be used to reconstruct melanin-based colour patterns in extinct animals.

Our team’s research has shown that fossil melanosomes can also help reconstruct the soft tissue anatomy of fossil animals, because melanosomes from different body tissues have different shapes and sizes. Our comprehensive examination of the fossilised soft tissues in Mirasaura, coupled with rigorous statistical analysis of the preserved melanosomes, reveals that their geometry is consistent with melanosomes in feathers, but not with melanosomes found in hair and in reptilian skin. This strongly suggests the Mirasaura skin appendages share common developmental features with feathers.

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Were the Mirasaura structures feathers, then? The solid, continuous blade of soft tissues either side of the central shaft shows no evidence for branching, which is a defining characteristic of most feathers in birds, dinosaurs and pterosaurs. The water is muddied, however, by the simple unbranched structure of some peculiar feathers in birds – such as the bristles of the turkey’s “beard”. Similar unbranched filaments are known in many dinosaurs and pterosaurs, and are widely considered to represent simple feathers.

Certain dinosaur fossils even have flattened, strip-like feathers that lack branching but possess a central shaft, considered by some experts to be an unusual – extinct – feather type. Whether the resemblance between these fossil structures and the Mirasaura skin outgrowths is superficial or belies closer evolutionary ties remains to be seen.

Intriguingly, research on the developing chick embryo shows that feathers can lose their branched structure when certain genes are manipulated. We are currently examining in greater detail the morphology and composition of the Mirasaura structures to help us interpret their anatomy more definitively.

Irrespective of what type of skin outgrowth they represent, our analyses of the anatomy of Mirasaura consistently position it, as well as other drepanosauromorph reptiles, at the base of the reptile tree. This supports data from developmental biology indicating that the genetic basis for the growth of complex skin appendages probably originated in the Carboniferous period, over 300 million years ago.

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Mirasaura therefore provides the first direct evidence that complex skin appendages did appear early during reptile evolution, and are not unique to pterosaurs, birds and other dinosaurs.

We owe these new insights to painstaking conservation efforts, which serve as a reminder of the critical importance of natural history collections in conserving our natural heritage.

The earliest discoveries of Mirasaura remains were unearthed in the 1930s by fossil collector Louis Grauvogel. After decades in the Grauvogel family, these specimens were donated to the State Museum of Natural History Stuttgart in 2019, where careful preparation revealed their true significance.

Now, the Mirasaura specimens force us to accept that even before the age of dinosaurs, reptiles were evolving striking anatomical traits normally associated with much younger fossils. This adds an intriguing dimension to future research into the origins of feathers, prompting palaeontologists to consider fossils from more diverse reptile groups – and from time periods before the appearance of dinosaurs and their direct ancestors.

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This article is republished from The Conversation under a Creative Commons license. Read the original article.

Valentina Rossi research is funded by the European Research Council. She is affiliated with University College Cork (UCC)

Maria McNamara receives funding from the European Research Council and Research Ireland.