An international research team has discovered that dinosaurs developed yearly growth lines on their bones throughout their lives, a find that sheds light on growth patterns of the ancient animals.
Scientists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) under the Chinese Academy of Sciences, together with the China University of Geosciences and the George Washington University, conducted the study and published it in the Journal of Vertebrate Paleontology.
Most modern mammals grow rapidly in their early years but develop dense lines of arrested growth in adulthood, a sign of cessation of growth. Modern reptiles, on the other hand, grow more slowly and keep growing throughout their lives, developing tree-ring-like growth lines on their bones every year.
According to the new research, dinosaurs may have followed growth patterns similar to those of modern reptiles.
The research team analyzed the bone tissues of Jeholosaurus, a small ornithopod dinosaur. They studied the specimens from five individuals at different growth stages, ranging from zero to five years old.
The research results showed that, while the growth rate of Jeholosaurus was obviously faster than that of modern reptiles, they also developed growth lines every year.
Environmental changes may be a cause of Jeholosaurus’ particular bone histology, but more evidence is required in order to reach a conclusion, said Xu Xing at the IVPP, one of the authors of the study.