The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus Author Paul, Gregory S. 3100 St. Paul St. 604, Baltimore, MD 21218, USA GSP1954@aol.com Author Iv, W. Scott Persons Department of Geology and Environmental Geosciences, College of Charleston, 202 Calhoun St, Charleston, SC 29401, USA Author Van Raalte, Jay 3100 St. Paul St. 604, Baltimore, MD 21218, USA text Evolutionary Biology 2022 2022-03-01 49 2 156 179 https://doi.org/10.1007/s11692-022-09561-5 journal article 10.1007/s11692-022-09561-5 df53e152-ad9e-4b59-b7a7-1ffec806ac46 6323344 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.