Tyrannosaurus imperator sp. nov. (Morphotype 1)

Etymology: Tyrant lizard emperor

Holotype: FMNH PR2081

Referred specimens: BHI 4182, BHI 6231, 6248, HMN MB.R.91216, MOR 1125, MOR 1128, RGM 792.000, SDSM 12047, TCM2001.90.1, TMT v2222, NMNNH P-3698?

Age and Stratigraphy: Late Maastrichtian, lower, lower middle and possibly middle Hell Creek and Lance, Laramie, Arapahoe, McRae? North Horn? Javelina?

Geographic distribution: Montana, Dakotas, Wyoming, New Mexico? Texas? Utah?

Diagnosis: Generally robust with an adult femur-length/ circumference ratio of 2.4 or less; usually two slender anterior incisiform dentary teeth.