Oldest Known Dome-Headed Dinosaur Rewrites Pachycephalosaur Evolution
ULAANBAATAR, Mongolia – Paleontologists have unearthed the oldest known example of a dome-headed dinosaur, Zavacephale rinpoche, in Mongolia’s Gobi Desert, challenging long-held beliefs about the evolution of these uniquely-skulled creatures.The finding, detailed in recent research, pushes back the origins of the domed head by tens of millions of years and suggests these structures developed earlier in pachycephalosaur evolution than previously thought.
Dating back to between 115 and 108 million years ago during the Early Cretaceous period, Zavacephale is significantly older than most other known pachycephalosaurs, which typically lived during the Late Cretaceous, between 80 and 66 million years ago. The remarkably well-preserved, though incomplete, specimen also indicates the dome was present even before the animal reached full size, contradicting the theory that the skull remained flat throughout youth and developed its dome in adulthood.
The find provides crucial insight into a group of dinosaurs known for their thickened skulls, often theorized to have been used for head-butting displays or combat. Previously, it was believed that pachycephalosaurs only evolved their domed skulls later in their evolutionary history.Zavacephale demonstrates that this characteristic was present much earlier, and perhaps developed alongside behaviors relating to display or combat during adolescence – a pattern observed in other non-bird dinosaurs.
further analysis of the zavacephale specimen revealed the presence of gastroliths, or stomach stones, with sharp edges, suggesting an omnivorous diet. This, coupled with the animal’s fang-like front teeth, indicates a broader dietary range than previously assumed for pachycephalosaurs and potentially points to widespread gastrolith use among dinosaurian omnivores and herbivores. The dinosaur’s long, slender hindlimb bones also suggest it was a swift runner.
The discovery was made by a team led by paleontologist Lindsay Zanno.Researchers have long sought more complete pachycephalosaur remains to better understand these rare dinosaurs, and Zavacephale represents a meaningful step forward in unraveling their evolutionary history.
