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.
During an expedition organized by the University of Alaska in 1999, a pachycephalosaur squamosal was discovered on bluffs near the Colville River bank in North Slope Borough, Alaska. The rock layers from this area are part of the latest Campanian-aged (72-71 mya) Prince Creek Formation. This fossil was later placed in the University of Alaska Museum and described by Roland Gangloff and colleagues as a pachycephalosaurine closely related to, and possibly, Pachycephalosaurus in 2005.