Birds were by no means the first to develop plumage. In recent years, countless fossil finds have demonstrated that many dinosaurs already wore plumage. The agile predatory microraptor not only had feathers, he could probably even glide with them. Other Cretaceous dinosaurs probably used their sometimes very colorful feather jewelry rather to courtship or to impress rivals. Even the fearsome Tyrannosaurus rex was probably already adorned with plumage. However, not all of these feathers already had a modern, bird-like structure. Fossil findings suggest that the plumage of early dinosaurs was more like the down of birds. The rare finding of a whole young dinosaur tail in amber recently proved that the stable spring shaft evidently originated later than the fine feather hairs. When the first airworthy feathers developed in non-bird dinosaurs and which dinosaurs were able to glide or even fly has so far been controversial.
More information about these questions could be provided by a fossil discovered by Xing Xu from the Institute of Vertebrate Paleontology of the Chinese Academy of Sciences in Beijing and his colleagues. The fossil comes from the west of the Chinese province of Liaoning, a region where many feathered dinosaurs have been found. In a roughly 100 to 145 year old rock formation, the paleontologists came across the almost complete skeleton of the Jianianhualong tengi baptized dinosaur. The anatomical comparative analysis showed that this animal is an early member of the so-called Troodontidae - a group of feathered dinosaurs, which include the already rather bird-like representatives Anchiornis and Jinfengopteryx. Jianianhualong was about a meter long during his lifetime and about as heavy as a parrot.
Long and asymmetrical
The really exciting thing about this new fossil, however, is its plumage: Jianianhualong wears long feathers on the arms, legs and back and tail. "This is an important demonstration of the presence of true feathers in early troodontids, " said Xu and his colleagues. While the front feathers of the fossil are not very well preserved, the structure and arrangement of the large tail feathers is clearly visible. "They form a tuft-like feathery tail and thus correspond more to a primitive type, " the researchers report. But the springs themselves are surprisingly modern. "Interestingly, a particularly well preserved lateral tail feather showed a relatively strong asymmetry, " said Xu and his colleagues. "The backward side is about twice as wide as the forward facing one." According to her, this is the earliest evidence of such an asymmetric spring in this group of dinosaurs - and a testament to the fact that such feathers were more common than before accepted. Previously, such very bird-typical feathers had been detected only on the forelegs of the Microraptor, in the troodontids, however, lacked such a document.
But how did the Jianianhualong use his feathers? Could he possibly fly already? This question can not answer the paleontologists. But: "The presence of these feathers indicates that these feathered dinosaurs had better aerodynamic capabilities than previously believed, " say the researchers. The asymmetrical tail feathers stabilize the air flow and thus the position of the animal. Whether Jianianhualong used these advantages only when running fast or already took off for short glides is still unclear. For this one would have to find further fossils of this kind, in which the feathers on the already slightly extended arms are completely preserved. display
- Xing Xu (Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences, Beijing) et al., Nature Communications, doi: 10.1038 / ncomms14972