Researchers in China have discovered the fossilized remains of a juvenile iguanodontian dinosaur from 125 million years ago, featuring exceptionally preserved skin and unique hollow spikes. This new species, named Haolong dongi, represents the first documented case of such structures in dinosaurs. The find challenges previous understandings of dinosaur anatomy.
Paleontologists have long studied Iguanodontia, a group of plant-eating dinosaurs known since the early 1800s for their beaked mouths and robust hind legs. A recent discovery adds a surprising member to this branch of the dinosaur family tree.
Scientists from the CNRS and partner institutions unearthed the well-preserved fossil of a young iguanodontian in China. Dating to the Early Cretaceous period, the specimen's skin is so detailed that individual cells remain visible after 125 million years. Advanced techniques, including X-ray scanning and high-resolution histological analysis of thin tissue slices, enabled examination at the cellular level.
The standout feature is the dinosaur's covering of hollow, cutaneous spikes embedded in the skin. Unlike bony horns or plates, these porcupine-like structures are not extensions of bone but originate from the skin itself. This is the first time such hollow skin-based spines have been observed in any dinosaur.
Named Haolong dongi in honor of Chinese paleontologist Dong Zhiming, the herbivorous dinosaur likely shared its ecosystem with small carnivorous predators. The spikes may have provided defense, similar to porcupine quills, by deterring attacks. Researchers also propose roles in thermoregulation, by aiding heat release or conservation through increased surface area, or in sensing environmental changes.
As the specimen is juvenile, it remains unclear if adults retained these spikes. The discovery, detailed in a study published on February 6, 2026, in Nature Ecology & Evolution, highlights greater variety in dinosaur skin and body coverings than previously known. The research was led by authors including Jiandong Huang and Pascal Godefroit, with the full paper available under DOI: 10.1038/s41559-025-02960-9.