On the famous Las Hoyas site in Spain, a team of paleontologists discovered the fossil of a 127 million-year-old prehistoric chick. The skeletal analysis under development will allow researchers to better understand the evolution of the first birds, at the time of the dinosaurs.
This little chick evolved during the Mesozoic (250-65 million years ago), 127 million years ago, when dinosaurs dominated the planet. It is part of a group of prehistoric birds called Enantiornithes. Composed of an almost complete skeleton, the specimen is one of the smallest Mesozoic avian fossils ever discovered. It is less than five centimeters – smaller than the little finger of your hand – and weighed about 85 grams at the time of his death.
What makes this fossil so important and so unique is that the chick died shortly after its birth: a crucial step in the formation of a bird’s skeleton. This means that the extremely short life of this animal will give researchers a rare opportunity to analyze the structure and bone development of the species. Studying ossification — the process of bone development — makes it possible to explain many things about the life of a young bird. “Evolutionary bird diversity presents a wide range of hatching development strategies and significant differences in their growth rates. By analyzing the development of the bones, we can deduce a host of evolutionary traits, “explains Fabien Knoll, of the Interdisciplinary Center for Ancient Life (ICAL) at the University of Manchester (United Kingdom), and lead author of this study.
For the analysis of this fossil, the researchers relied on three synchrotrons. These super-generators of X-rays are indeed more and more used for scientific research. In particular, they revolutionize paleontology, decrypting fossils, and thus the distant past of living beings: “New technologies offer paleontologists unprecedented capacity to investigate fossils,” he says. “We have made the most of state-of-the-art facilities around the world, including three different synchrotrons in France, the United Kingdom and the United States.”
The researchers then discovered that the bird’s sternum was still largely cartilage and had not yet developed into hard, sturdy bone at the time of death, which meant it could not fly. The patterns of ossification observed in this bird and other very young birds in the category of Enantiorniths known to date also suggest that the development strategies of this particular group of ancient avians may have been more diverse than thought before.
However, the team notes that its lack of bone development does not necessarily mean that the newborn was dependent on its parents for care and feeding. The researchers think that even if the bird was very vulnerable, it could have fed itself.