Scientists have recently unearthed a fascinating species of pachycephalosaur, known as Platytholus clemensi, believed to have existed approximately 68 million years ago. The researchers from UC Berkeley and Chapman University have utilized CT scans to examine the domes of certain pachycephalosaurs and have uncovered intricate structures that adorned their skulls.
When examining dinosaur fossils, one can observe a remarkable array of bony adornments on their skulls, ranging from the imposing horns of Triceratops to the mohawk-like crests of the Hadrosaurs, as well as an assortment of bumps and knobs on the head of the Tyrannosaurus Rex.
However, paleontologists are now uncovering evidence suggesting that dinosaurs possessed even more elaborate head decorations that may not have been preserved in the fossil record. These structures, made of keratin—a material similar to human fingernails—likely served as visual signals or semaphores to communicate with others of their kind.
The recently described dome-headed dinosaur species, a pachycephalosaur from the Cretaceous period, provides the latest example. Pachycephalosaurs, small-to-medium-sized plant eaters, roamed the Earth between 130 and 66 million years ago. These bipedal creatures, measuring between 3 to 15 feet in length, possessed a long, rigid tail for balance.
The discovery of this new species is based on a partially preserved pachycephalosaur skull, including its distinct dome shape, which was excavated in 2011 from the Hell Creek Formation in Montana—a site known for its rich dinosaur fossils. Through CT scans and microscopic analyses, paleontologists Mark Goodwin of UC Berkeley and John “Jack” Horner of Chapman University have concluded that the skull likely supported bristles of keratin, resembling a brush cut.
“We cannot determine the exact structure that covered the dome, but we believe it had a vertical component covered in keratin,” stated Goodwin. He further noted that a bristly, flat-topped covering is biologically plausible, as animals often modify or utilize certain skull features for multiple purposes, such as display or social and biological interactions involving visual communication.
Horner, a distinguished paleontologist, lecturer, and presidential fellow, shared his thoughts on the discovery, stating, “I speculate that there may have been something quite elaborate on top of the dinosaur’s head.” As a professor emeritus at Montana State University and an emeritus curator at the Museum of the Rockies, Horner has made significant contributions to the field.
Interestingly, the skull of the specimen exhibited a notable gouge at the apex, indicating that the dinosaur had suffered a severe injury. Remarkably, the creature survived long enough for new bone tissue to heal the wound.
Goodwin explained, “This is perhaps the first definitive evidence of head trauma in any pachycephalosaur, where the bone was expelled from the dome and partially healed during the creature’s lifetime.” While head-butting is a plausible explanation, the researchers caution that the injury could have resulted from various factors, such as a falling rock or an encounter with a tree or another dinosaur.
Detailed examinations of the tissues underlying the dome in this and other pachycephalosaur skulls have failed to provide histological evidence supporting the theory that these dinosaurs engaged in head-butting behavior. Goodwin and Horner contend that the internal structure of pachycephalosaur skulls lacks the necessary features to sustain such collisions without causing severe brain damage.
Horner emphasized that head-butting is predominantly observed in mammals and is rarely seen in reptiles or birds, the latter of which include the dinosaur descendants.
Frequently Asked Questions (FAQs) about dome-headed dinosaur
What is the significance of the newly discovered dome-headed dinosaur species?
The newly discovered dome-headed dinosaur species, Platytholus clemensi, challenges previous assumptions about head-butting behavior in dinosaurs. It provides evidence of intricate headgear made of keratin and suggests alternative purposes such as visual communication or display.
How did scientists study the dome structures of pachycephalosaurs?
Scientists used CT scans and microscopic analyses of sliced fossils to examine the dome structures of pachycephalosaurs. These techniques allowed them to study the internal features and identify the presence of bristles made of keratin.
What is the proposed function of the keratin structures on the dinosaur’s dome?
The keratin structures on the dinosaur’s dome were likely used for visual communication or display. They may have served as visual signals to communicate with others of their kind, potentially indicating gender or playing a role in courtship rituals.
Is there evidence of head-butting behavior in pachycephalosaurs?
No, there is no histological evidence supporting the theory of head-butting behavior in pachycephalosaurs. The internal structure of their skulls lacks the adaptations necessary to withstand head-to-head collisions without causing severe brain damage.
What caused the injuries observed on the dome of the newly discovered species?
The injuries observed on the dome of the newly discovered species were likely caused by various factors, such as falling rocks, encounters with trees, or interactions with other dinosaurs. While head-butting is a possibility, it cannot be definitively attributed as the cause.
More about dome-headed dinosaur
- Journal of Vertebrate Paleontology: A new pachycephalosaurid from the Hell Creek Formation, Garfield County, Montana, U.S.A.
- Smithsonian Institution: Smithsonian National Museum of Natural History
- University of California, Berkeley: UC Museum of Paleontology
- Chapman University: Official Website
- National Science Foundation: NSF Website
- Royal Ontario Museum: Official Website
- Hell Creek Formation: Montana Geological Society
- Cretaceous Period: Encyclopedia Britannica