New species of feathered dinosaur discovered in Northeast China

China News Service, Beijing, October 3 (Reporter Sun Zifa) A new paleontology paper published in Nature Communications, an academic journal of Springer Nature, stated that researchers discovered a new feathered dinosaur fossil in the strata of Northeast China about 145 million to 100 million years ago, named Norysaurus barensis. Their research and analysis provides new evidence for the theory that "different groups of bird-like dinosaurs have differences in the evolution of flight-related characteristics."

Left: The fossilized appendage skeleton of Norelosaurus barbari; Right: Artistic restoration of Norelosaurus barbari (drawn by Zhang Chuang). Photo courtesy Springer Nature

This research was led by Chinese scholars and completed in conjunction with collaborators from Italy, Slovakia and others. They said that the new dinosaur species Norysaurus barbari was discovered in a Lower Cretaceous stratum in Liaoning Province. It is an extremely well-preserved microraptor fossil (a small dinosaur with feathers and wings). Its complete skeleton is 57 centimeters long, and part of the feather structure is preserved.

Microraptors were small, bird-like carnivorous dinosaurs and close relatives of birds. Fossils of these feathered dinosaurs are often found in northeastern China. Fossils show that some microraptors had long feathers on their forelimbs and hindlimbs, suggesting they may have been adapted for flight.

Fossils of Norelosaurus barbari (picture from the paper). Photo courtesy Springer Nature

Whether these traits mark the origin of flight adaptations in Anchiornis (a group that includes microraptors and birds) or whether they evolved independently remains an open question, although available evidence suggests the latter theory is more credible.

Analysis of the fossilized Norysaurus barensis revealed that the individual was at least three years old when it died and displayed a range of flight-related characteristics. The researchers compared these results with evolutionary trees and found that about 30 percent of the anatomical changes identified during the evolution of microraptors also evolved in the bird lineage. However, there are differences in the order in which these common features appear in the two taxa.

The evolutionary sequence of evolutionary characteristics shared by Microraptor and ornithomorphs (picture from the paper). Photo courtesy Springer Nature

The findings challenge the idea that microraptors and birds inherited a common flight structure or shared developmental processes that drove the evolution of this structure, the authors said.

They concluded that different selective pressures likely shaped flight-related traits in each lineage, and further fossil and skeletal growth evidence will be needed to verify how common this pattern was among bird-like dinosaurs. (over)