The Skull of a Pachycephalosaurus
Late Cretaceous Period, Maastrichtian Stage (approx. 72 to 66 million years ago), Hell Creek Formation, Perkins Co., South Dakota
Auction Closed
July 16, 06:46 PM GMT
Estimate
800,000 - 1,200,000 USD
Lot Details
Description
The Skull of a Pachycephalosaurus
Pachycephalosaurus wyomingensis
Late Cretaceous Period, Maastrichtian Stage (approx. 72 to 66 million years ago)
Hell Creek Formation, Perkins Co., South Dakota
This outstanding specimen, measuring approximately 21 inches long, 15½ inches high, and 10½ inches wide, represents a virtually complete skull plus dentition belonging to a Pachycephalosaurus dinosaur, consisting of an incredible 32 cranial bones, plus the atlas, both hyoid bones, two premaxillary fangs, and two maxillary teeth. The articulated bones of the skull are preserved in good detail, showing much of their original shape and surface ornamentation. The left side of the skull, the orbits and infratemporal fenestra including the surrounding bones (supraorbital, postorbital, jugal, quadrate, etc.) around these openings are mostly intact, with small sections of the right side of the skull restored and reconstructed, including the lower jaws.
This specimen displays cranial features characteristic of the species including the well-developed dome with clusters of horns on the nasal, jugal, and squamosal. The specimen belonged to a fairly mature individual based on the proportionately large dome against the short squamosal horns, overall size, and fusion of cranial bones.
Excavated in 2024 on privately owned land in the Hell Creek Formation, Perkins County, South Dakota
Pachycephalosaurus is the largest and best known of the dome-headed dinosaurs, and can only be found in North America. The most infrequently occurring fossil from the Late Cretaceous of North America, it represents less than 1% of fossils found in the Hell Creek Formation. In contrast, Triceratops fossils represent 40%. There are fewer than twenty-five, mostly incomplete, Pachycephalosaurus skulls housed in institutions and private collections, making this virtually complete skull an incredibly important find.
THE CALLING CARD OF A FAMOUS DINOSAUR
Though their distinctive domed skulls are famous among dinosaurs, Pachycephalosaurus (“thick headed lizard”) remain shrouded in mystery. The present lot demonstrates the most famous aspect of an already famous dinosaur: its iconic skull, with which in art and exhibition, Pachycephalosaurus is often portrayed using to ram its natural enemy T. rex.
Notably, this skull features a virtually complete upper jaw, demonstrating the dinosaur’s unusual teeth. Pacycephalosaurus were herbivorous, though the unusual sharpness and structure of their teeth have led some scientists to believe that these creatures may have been omnivorous.
A CASE OF MISTAKEN IDENTITY
The first fragments of Pachycephalosaurus remains were discovered in the early 1860s by American fossil collector Ferdinand Vandeveer Hayden in what is now known as the Lance Formation in Montana. At the time, the paleontological community thought the remains could be those of an armadillo-like creature and named it Tylosteus. In 1943, Barnum Brown and Erich Maren Schlaikjer coined the name Pachycephalosaurus after more fossils were discovered. The original remains found by Vandeveer Hayden would not be associated with Pachycephalosaurus until the 1980s.
The confusion over the species persisted into the 2010s and present day as more and more researchers suggest that other specimens believed to be separate species such as Stygimoloch and Dracorex, may instead be attributed to a juvenile Pachycephalosaurus.
LITERATURE:
- Horner JR, Goodwin MB, Myhrvold N (2011) Dinosaur Census Reveals Abundant Tyrannosaurus and Rare Ontogenetic Stages in the Upper Cretaceous Hell Creek Formation (Maastrichtian), Montana, USA. PLoS ONE 6(2): e16
- Horner JR, Goodwin MB (2009) Extreme Cranial Ontogeny in the Upper Cretaceous Dinosaur Pachycephalosaurus. PLoS ONE 4(10): e7626