The group of iguanas, known to scientists for 200 years, has been supplemented by a new species – the first among spiny dinosaurs with previously unknown properties. Superbly preserved remains have been found in China.
The discovery was a skeleton with fossilized skin. It was studied by paleontologists from the French National Center for Scientific Research (CNRS) and their colleagues from other countries, the results of which were published in the journal Natural Ecology & Evolution.
Using X-ray scans and highly precise histological sections, researchers examined skin cells that have been around for about 125 million years and revealed the structure of the hollow skin spikes that cover much of the animal's body. The new species was named Haolong dongi, in honor of the pioneer of Chinese paleontology, Dong Zhiming.
“We discovered that these were neither feathers nor hair. These were structures similar to spines, but at the same time not completely alien to feathers. The difficulty of this work was precisely in not giving in to the first impression and saying: “We found something that resembles feathers.” No, this is really something else and absolute precision is required here. Exactly,” said paleontologist Ninon Robin from the University of Rennes, lead author of the paper.
According to her, while studying the sample, one of the spikes broke.
“But for us, this is even better: we were only interested in looking inside and understanding what it consists of. We saw that at the end of the branch is a homogeneous monolithic structure. And closer to the base, it consists of an outer compact layer (cortex) and a more porous central core (medulla)”, shares the researcher.
This spiny dinosaur was herbivorous and lived under constant threat from small carnivorous dinosaurs. Its spines, which have a restraining function similar to those of a porcupine, represent a unique evolutionary process. They may also play a role in temperature regulation or sensory perception.
To date, there is no evidence of such spikes on dinosaurs. Since the remains found of H. dongi belong to a subadult, it remains to be seen whether these spines are preserved in the adult.
For the first time, traces of an armored dinosaur with a club tail were found in Canada.
