Studied dinosaur specimen NJUES-10 under natural (upper half) and UV light (lower half) showing the orange-yellow fluorescence of the fossil skin. Credit: Dr. Zixiao Yang
A study by University College Cork reveals that the feathered dinosaur Psittacosaurus also had reptilian-like scaly skin, offering new insights into the evolutionary transition from scales to feathers.
- Researchers found ‘zoned development’ in dinosaur skin, with zones of reptile-style scales and zones of bird-like skin with feathers
- New dinosaur skin fossil discovered to be composed of silica – the same material found in glass
- Discovery sheds light on the evolution from scales to feathers
Paleontologists in Ireland have uncovered evidence that certain feathered dinosaurs had scaly skin like reptiles today, offering new insights into the evolutionary shift from scales to feathers.
In their research, the scientists examined a newly discovered specimen of the feathered dinosaur Psittacosaurus, dating back to the early Cretaceous period (135–120 million years ago)—a crucial era for the evolution of dinosaurs into birds. This study revealed, for the first time, that areas of the Psittacosaurus not covered in feathers exhibited skin similar to that of modern reptiles.
The study, published today (May 21) in Nature Communications, was led by University College Cork (UCC) paleontologists Dr. Zixiao Yang and Prof. Maria McNamara of UCC’s School of Biological, Earth and Environmental Sciences, who teamed with scientists based in Nanjing University (China).
The fossil skin under an electron microscope, showing mineralized cell layers. Credit: Dr. Zixiao Yang
The team used ultraviolet (UV) light to identify patches of preserved skin, which are invisible in natural light. Further investigation of the fossil skin using X-rays and infrared light revealed spectacular details of preserved cellular structure.
Insights From Psittacosaurus Specimen
Dr. Yang says: “The fossil truly is a hidden gem. The fossil skin is not visible to the naked eye, and it remained hidden when the specimen was donated to Nanjing University in 2021. Only under UV light is the skin visible, in a striking orange-yellow glow.
“What is really surprising is the chemistry of the fossil skin. It is composed of silica – the same as glass. This type of preservation has never been found in vertebrate fossils. There are potentially many more fossils with hidden soft tissues awaiting discovery.”
Dr. Zixiao Yang of University College Cork, who discovered that some feathered dinosaurs had scaly skin like reptiles today, thus shedding new light on the evolutionary transition from scales to feathers. Credit: Ruben Tapia/UCC TV
Evolutionary Implications
The most exciting aspect of the discovery, however, is what it tells us about the evolution of feathers in dinosaurs. Prof. McNamara, senior author on the study, says:
“The evolution of feathers from reptilian scales is one of the most profound yet poorly understood events in vertebrate evolution. While numerous fossils of feathers have been studied, fossil skin is much more rare.
“Our discovery suggests that soft, bird-like skin initially developed only in feathered regions of the body, while the rest of the skin was still scaly, like in modern reptiles. This zoned development would have maintained essential skin functions, such as protection against abrasion, dehydration, and parasites. The first dinosaur to experiment with feathers could therefore survive and pass down the genes for feathers to their offspring.”
The Psittacosaurus specimen NJUES-10 is currently housed in Nanjing University.
Reference: “Cellular structure of dinosaur scales reveals retention of reptile-type skin during the evolutionary transition to feathers” 21 May 2024, Nature Communications.
DOI: 10.1038/s41467-024-48400-3