A newly discovered dinosaur from China is shaking up what we know about the Iguanodon group. This dinosaur, called Haolong dongi, challenges the idea that these creatures were entirely scaly. Instead, it shows they had short spikes along their bodies.
A team of researchers from China, Belgium, France, and Italy led by Jiandong Huang and Pascal Godefroit published their findings in Nature Ecology & Evolution. Haolong, which means “spiny dragon,” honors the late dinosaur expert Dong Zhiming.
The specimen is 2.4 meters long, indicating it was still a juvenile. Experts estimate that, as adults, these dinosaurs could have reached around 5 meters. Haolong belongs to the iguanodontian family, known for including the famous thumb-spiked Iguanodon and hadrosaurs, or duck-billed dinosaurs. These creatures are part of a larger group called ornithischians, which also includes armoured dinosaurs like ankylosaurs and the horned Triceratops.
What makes this find exciting is the exceptional preservation of its bones and surrounding soft tissue. Researchers used advanced techniques, including laser-stimulated fluorescence, to examine the skin down to the cellular level. They found that Haolong had cylindrical spikes projecting from its neck and body, some as tiny as 2-3 mm and others reaching lengths of up to 4 cm. These spikes resemble porcupine quills, hinting at a unique form of skin structure.
Along with the spikes, the dinosaur had various tiny scales typical of its kind. Uniquely, it also featured large, overlapping scales along its tail, arranged in rows. This differs significantly from other iguanodontians, suggesting that Haolong had a distinct skin texture compared to its relatives.
Interestingly, tail scales similar to those of Haolong were previously found in another dinosaur, Kulindadromeus, indicating that such features evolved independently in these species. Recent discoveries show some ornithischians, like certain small dinosaurs, had long filaments covering their bodies, reminiscent of feathers. Haolong’s spikes might highlight the diverse skin types among dinosaurs, far more complex than just scales or feathers.
So, why did Haolong have these spikes? Researchers initially considered whether they might serve a sensory purpose but ruled that out. Instead, they believe the spikes could have deterred predators, especially since Haolong lived in a cool environment with an average temperature of around 10°C. While they may not have provided insulation like feathers or bristles, they likely played a role in survival.
As paleontologists continue to uncover information about ornithischian skin, artists are reimagining these dinosaurs with intricate coverings and structures. Haolong supports the idea that spikes were possibly more common among iguanodontians, even if many did not preserve as well.
This discovery not only unveils new details about Haolong dongi but also deepens our understanding of dinosaur diversity. As experts, like Godefroit, point out, there’s still much to learn about how these unique features were preserved.
For those interested in dinosaur discoveries, this find is just one of many that reshapes our view of these ancient creatures. The ongoing research not only enriches our understanding of the past but also inspires curiosity about the diverse forms of life that once roamed the Earth.
For more on these findings, check out the research from Nature Ecology & Evolution here.
