Rare dome-headed baby dinosaur fossil found in Canada

Fossil of a Pachycephalosaurus baby with a domed skull found in southern Saskatchewan, Canada, marks a breakthrough in palaeontology. Until now, knowledge of domed-headed dinosaurs has been limited because fossil records have been dominated by skulls, while other skeletal remains are rarely found.

However, the newly identified specimen, catalogued as CMNFV 22039 and estimated to be 67 million years old, provides a rare glimpse into the physical appearance and development of these dinosaurs in their first months of life.

A palaeontologist from Carleton University, Bryan Moore, explains that Pachycephalosauria generally comprises small bipedal dinosaurs ranging from two to six metres in length that lived in Asia and North America.

Their main distinctive feature is the fusion of frontal bones forming a prominent dome, often ornamented with spikes or bone nodules. Because this dome structure is very robust and more resistant to natural damage than other parts of the body, scientists have historically relied on skull morphology to study the growth of these species.

Interestingly, the fossil found at the Frenchman Formation is believed to belong to a baby dinosaur that died before reaching one year of age.

Although tiny, with an estimated total length of just 90 centimetres, the skeleton already shows the distinctive characteristics of an adult Pachycephalosauria. This proves that the major physical identity of the domed-headed dinosaurs was already formed when they were still very young, not only appearing as they grow older.

Moreover, the discovery reveals differences in movement between juveniles and adults. Based on researchers’ observations, baby Pachycephalosaurus had hind limbs that are proportionally much longer than their bodies.

This proportion suggests that in early life, the dinosaur had a more agile, speed-oriented form to survive. As they aged and gained weight, their bodies would shift to a more robust form, indicating a change in locomotion with physical growth. (Sci News/Z-10)

Palaeontologists have found the oldest and most complete domed-headed Pachycephalosaurus fossil in the Gobi Desert, Mongolia.