Analysis of fossilized remains from dinosaurs known as troodontids reveals how one species' hip and leg bones may have developed over its lifespan, from embryo to adult—with potential implications for resolving longstanding taxonomic challenges. David Varricchio of Montana State University, U.S., and Heath Caldwell of North Carolina State University, U.S., present their findings in the journal PLOS One on Sept. 9, 2026.