Tiny to towering: Montana Troodon fossils reveal full growth from embryo to adult

New Montana Troodon formosus fossils provide a near-complete record of pelvic and hindlimb ontogeny from embryo to adult, revealing mostly consistent bone shapes across growth with stage-specific changes in bone strength, texture, and fusion; the femur lengthens relative to the tibia in adults, indicating steady growth. The sample also shows adult size variation and common foot pathologies, and it underpins a proposed taxonomic shift away from a tooth-based type specimen to pelvic/hindlimb fossils, pending ICZN approval. Together, the findings illuminate locomotion and life history in troodontids.