Contact: Robert Sanders
University of California - Berkeley
Caption: Cross-sections through the fossilized tibia or shinbone of a 120 million-year-old female Tenontosaurus skeleton, showing growth rings and medullary bone laid done in the marrow cavity just prior to egg laying. This individual died at the age of eight, shortly before she would have laid her eggs.
Credit: Sarah Werning/UC Berkeley & Andrew Lee/Ohio University; fossils courtesy of the Oklahoma Museum of Natural History
Usage Restrictions: None
Related news release: Rapid growth, early maturity meant teen pregnancy for dinosaurs