In a groundbreaking discovery, paleontologists have struck gold in Mongolia's Gobi Desert with the oldest and most complete dome-headed dinosaur fossils ever found!

These fascinating fossils date back an astonishing 108 to 115 million years, pushing the timeline for dome-headed dinosaurs, or pachycephalosaurs, back by an extra 15 million years. This find may uncover secrets about how these unique creatures developed their bizarre dome-shaped skulls.

Study co-author Lindsey Zanno, a paleontologist from North Carolina State University, describes pachycephalosaurs as, iconic yet enigmatic. These dinosaurs flourished during the Late Cretaceous period, around 86 to 66 million years ago.

Debates rage among scientists about the purpose of the pachycephalosaurs thick skulls: did they use them to attract mates or fend off rivals? Some even speculate they might have engaged in kickboxing rather than butting heads! How their unique skulls came to be remains largely a mystery.

In a pivotal study just published in *Nature*, the research team proudly introduces a remarkable fossil discovery: a dome-headed dinosaur from the Early Cretaceous period, named *Zavacephalae rinpoche*.

The name *Zavacephalae* combines Tibetan and Latin terms that mean root or origin of the head, while *rinpoche*, meaning precious one, reflects how the skull was found protruding from a cliff like a rare gemstone.

This incredible fossil includes approximately 54% of the dinosaur's bones—featuring its complete skull and tail, along with leg bones and stomach stones designed for grinding food. When alive, *Z. rinpoche* likely measured around 3.3 feet (1 meter) and weighed about 12.9 pounds (5.85 kilograms).

Zanno notes, Unlike most pachycephalosaurs with only fragmentary skulls, *Z. rinpoche* is a sensational find that links the growth stages of this dinosaur directly to its dome development for the very first time!" Through the growth rings in its leg bones, researchers determined that while its dome was fully developed, this creature was still a juvenile at the time of its death.

This intriguing detail indicates that these dinosaurs likely reached sexual maturity before they were physically fully developed. As Zanno quips, If you need to headbutt your way into a relationship, it’s smart to start rehearsing early!

Zanno concludes, This specimen is a once-in-a-lifetime discovery that offers unprecedented insight into the anatomy and biology of these astonishing creatures.