Overview
- The peer-reviewed study describes a juvenile iguanodontian from the Early Cretaceous Yixian Formation with porcupine-like, hollow spikes arising from the skin.
- X‑ray scans and ultrathin histological sections documented cellular-level preservation that reveals the spikes’ keratinous composition.
- The fossil, dating to about 125 million years ago, was discovered near the village of Xiawujiazi in Liaoning Province.
- The species is named Haolong dongi in honor of paleontologist Dong Zhiming and is placed within Iguanodontia, a lineage that includes the ancestors of duck-billed dinosaurs.
- The research team proposes defensive, thermoregulatory, or sensory roles for the spikes, while noting the juvenile specimen leaves their persistence into adulthood unresolved.