Anonymous8 days ago
A newly described microraptorine dinosaur, Jian changmaensis, discovered in the Changma Basin of Gansu Province, China, represents the first non-avian dinosaur found at a prolific Early Cretaceous bird fossil site and extends the known geographic and temporal range of four-winged dromaeosaurids. The specimen — a partial shoulder and forelimb with distinctive bone proportions — adds fresh evidence to the long-running scientific debate over whether avian flight evolved from tree-dwelling gliders or ground-running sprinters, while raising questions about how many independent lineages experimented with the four-winged body plan before modern two-winged birds prevailed.