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 regina sp. nov. (Morphotype III) Etymology : Tyrant lizard queen. Holotype : USNM 555000 Referred specimens : exBHI 3033 , MOR 980 , LACM 23485 , LL 12823 , TMP 81.6.1 , LACM 23845 . Age and stratigraphy : Latest Maastrichtian, upper and possibly middle Hell Creek and Lance, Ferris, Denver, Frenchman, Willow Creek, Scollard. Diagnosis : Generally gracile with an adult femur-length/ circumference ratio over 2.4, usually one slender anterior incisiform dentary tooth. Geographic distribution : Montana, Colorado, Dakotas, Wyoming, Alberta, Saskatchewan.