In 1999 during an expedition by the University of Alaska, an isolated pachycephalosaur squamosal was unearthed from bluffs on the bank of the Colville River in North Slope Borough, Alaska. Strata (rock layers) deriving from this area come from the latest Campanian-aged (72-71 mya) Prince Creek Formation. The fossil was then deposited in the University of Alaska Museum and described in 2005 by Roland Gangloff and colleagues as belonging to a pachycephalosaurine closely related to, and possibly, Pachycephalosaurus.
In 1999 during an expedition led by the University of Alaska, a pachycephalosaur squamosal was unearthed on bluffs along the Colville River bank within North Slope Borough, Alaska. The rock layers from this region are from the latest Campanian-aged (72-71 mya) Prince Creek Formation. This fossil was later deposited in the University of Alaska Museum and described by Roland Gangloff and colleagues as belonging to a pachycephalosaurine closely related to, and possibly, Pachycephalosaurus.