Fossil skull of Pachycephalosaurus wyomingensis. Specimen AMNH 1696, collected in 1940 by WH Peck and TG Nielsen near Ekalaka in Carter County, Montana, currently on display at the American Museum of Natural History in New York.
<a href="//commons.wikimedia.org/wiki/User:P2N2222A" class="mw-redirect" title="User:P2N2222A">Skye McDavid</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>