Meetings

The question of how Tyrannosaurus rex attained such remarkable proportions has fascinated children and paleontologists alike since their first discovery. Los Angeles' own Natural History Museum has a unique growth series of juvenile and teenage T. rex, which gives us a glimpse into the development of these terrifying giants. By examining thin slices of limb bones or ribs under a microscope, we are able to assess age and reconstruct the growth patterns of these long-dead animals. However, what happens when you are uncertain if your fossil is a juvenile T. rex, or an entirely different species? What if this fossil is only a skull, without limbs or ribs to study? This is the story of how a small bone in the throat - the hyoid - solved an 80-year-old mystery and ultimately resurrected Nanotyrannus!

Dr. Zachary Morris is a Postdoctoral Fellow at the Natural History Museum of Los Angeles County's Dinosaur Institute, who studies the developmental factors generating patterns in the fossil record. His research employs tools from paleontology, comparative anatomy, and experimental embryology to understand how the head has been modified across vertebrate evolution. When he is not in the field digging up new fossils or studying existing museum collections, he collects alligator eggs to understand how embryonic development itself evolves. His current work includes reconstructing the soft tissue of the roof of the mouth in tyrannosaurs, and how changes in the embryonic development enabled the evolution of faces as different as chickens, lizards, and crocodiles.