The discovery of a reptile with feather-like structures that have lived before the dinosaurs raises many questions among scholars of the evolution of birds. A new study confirms the animal nature of this discovery but explained that … they are not feathers, even though they share many characteristics with feathers.
The oldest dinosaur remains discovered so far 230 million years ago, from the Triassic period. Animals of that time were without feathers. Indeed, the oldest animals with these outgrowths, is an animal with size of a pigeon belonging to the species Epidexipteryx hui, is dated from 152 to 168 million years (Jurassic). As we know that living birds descended directly from dinosaurs.
However, a small reptile disturbs these proposals. Having lived there 230 to 240 million years ago, it would be older than the earliest dinosaurs, however, it has what looks like feathers ! The intruder is called Longisquama insignis. The one and only fossilized specimen identified to date was discovered in Kyrgyzstan in the 1960s. For some scientists, a minority, it is the true ancestor of birds. For others, this animal would have simply been buried along with exotic plants. So the “feathers” were not actually part of the animal.
Michael Buchwitz from the Freiberg University of Mining and Technology (Germany) provides a new explanation in the journal Zeitschrift Paläontologische. He said these structures are of animal origin, but they are neither scales nor feathers. They are perhaps linked to the early evolution of dino and pterosaur fuzz.
Yes, the feathers are well emerged in dinosaurs!
Michael Buchwitz began its work by reconsidering the only fossil fuel available. He said that the integument appendages penetrate well into the body of the animal. Their bases should be located near the spine, which means they were deeply rooted in the skin. The animal is therefore confirmed. But can we talk about feathers?
Outgrowths are well preserved, but not attached to a body, were also found near the site of the discovery of Longisquama insignis. The fossil record showed no presence of beards or barbels. Moreover, the structure of integumentary outgrowths does not vary along their lengths and each edge has a particularly unmatched rigid of today. In conclusion, it is not feathers. However, it is true that there are similarities, including the presence of the central protofilament. That’s why the author believes that the genes involved in the development of feathers could encode the formation of these structures.
According to Michael Buchwitz, the skeleton is not complete enough to determine its precise location within the development but it probably belongs to the lineage that gave rise to pterosaurs, crocodiles, dinosaurs and birds.
Many of these groups later evolved their own skin appendages, including filaments on pterosaur wings, quills on the tails of some plant-eating ornithischian dinosaurs, and the proto-feathers of theropod dinosaurs.
Longisquama shows that evolution was experimenting with the genes that gave rise to feathers long before any of these animals appeared on the scene.
“It’s a very impressive analysis,” said Alan Brush, a feather specialist at the University of Connecticut in Storrs.