The
Platytholus holotype specimen, MOR 2915, was discovered during the early 2000s in sediments of the
Hell Creek Formation, dated to the latest
Maastrichtian age of the late
Cretaceous period, in
Garfield County,
Montana. The specimen consists of a partial skull. In 2023,
Horner, Goodwin &
Evans described Platytholus clemensi, a new genus and species of pachycephalosaurid, based on these fossil remains. The
generic name, "
Platytholus", combines the
Latinised Greek "platys", meaning "flattened", "wide", or "broad", and "tholos", meaning a "small domed hill". The
specific name, "
clemensi", honors American paleontologist
William A. Clemens Jr. == Classification ==