Researchers from CNRS and associated institutions have made a groundbreaking discovery in China, unearthing the fossilized remains of a remarkably preserved young iguanodontian. This specimen stands out not only for its skeleton but also for its preserved skin, a rare occurrence for soft tissues to survive over millions of years. Remarkably, even microscopic details of the skin have been maintained.
Fossilized Skin and Ancient Cellular Preservation
Employing cutting-edge imaging methods such as X-ray scanning and high-resolution histological analysis, the team examined the fossil at a cellular level. They determined that individual skin cells had survived for approximately 125 million years, allowing scientists to reconstruct the structure of distinctive hollow spikes found within the skin.
These spikes, termed cutaneous due to their skin origin, were prevalent across much of the dinosaur's body. Unlike solid horns or bony plates, these structures were hollow, a feature never before documented in dinosaurs. The newly identified species has been named Haolong dongi, in honor of Dong Zhiming, a renowned Chinese paleontologist who significantly advanced dinosaur research in China.
Defensive Adaptations and Potential Functions
Haolong dongi was a herbivore, primarily feeding on plants. During the Early Cretaceous period, it coexisted with small carnivorous dinosaurs. The hollow spikes may have served a defensive purpose, acting similarly to porcupine quills to deter predators.
However, their function may extend beyond defense. Researchers propose that the spikes could have played a role in thermoregulation, aiding in heat release or conservation due to their increased surface area. Additionally, these spikes might have had sensory functions, enabling the dinosaur to sense movement or environmental changes.
A Unique Discovery in Paleontology
This fossil represents a first-of-its-kind discovery, providing evidence that dinosaurs had hollow skin-based spines. As the specimen is juvenile, it remains uncertain whether adult individuals of the species maintained the same structures as they matured. Further research is necessary to explore this aspect.
The findings, published in Nature Ecology & Evolution on February 6, 2026, introduce a novel feature to the known diversity of dinosaur anatomy. This discovery not only adds a new species to the Iguanodontia group but also enhances our understanding of the variety and complexity of dinosaur skin and body coverings.