biostudies-literatureUnknown10Warshaw EAThe US Bureau of Land ManagementDestiny and Craig WolfCity of Dickinson, NDConoco-PhillipsGoogle EmployeesTC Energy EmployeesTC EnergyHere we describe a new derived tyrannosaurine, <i>Daspletosaurus wilsoni</i> sp. nov., from Judithian strata (~76.5 Ma) intermediate in age between either of the previously described species of this genus. <i>D. wilsoni</i> displays a unique combination of ancestral and derived characteristics, including a cornual process of the lacrimal reduced in height relative to <i>D. torosus</i> and more basal tyrannosaurines, and a prefrontal with a long axis oriented more rostrally than in <i>D. horneri</i> and more derived tyrannosaurines. The description of this taxon provides insight into evolutionary mode in Tyrannosaurinae, lending strength to previous hypotheses of anagenesis within <i>Daspletosaurus</i> and increasing the resolution with which the evolution of this lineage can be reconstructPeerJe14461https://www.ebi.ac.uk/biostudies/studies/S-EPMC9703990biostudies-literatureA transitional species of <i>Daspletosaurus</i> Russell, 1970 from the Judith River Formation of eastern Montana.PMC9703990Warshaw EAFowler DWfalseA transitional species of <i>Daspletosaurus</i> Russell, 1970 from the Judith River Formation of eastern Montana.Here we describe a new derived tyrannosaurine, <i>Daspletosaurus wilsoni</i> sp. nov., from Judithian strata (~76.5 Ma) intermediate in age between either of the previously described species of this genus. <i>D. wilsoni</i> displays a unique combination of ancestral and derived characteristics, including a cornual process of the lacrimal reduced in height relative to <i>D. torosus</i> and more basal tyrannosaurines, and a prefrontal with a long axis oriented more rostrally than in <i>D. horneri</i> and more derived tyrannosaurines. The description of this taxon provides insight into evolutionary mode in Tyrannosaurinae, lending strength to previous hypotheses of anagenesis within <i>Daspletosaurus</i> and increasing the resolution with which the evolution of this lineage can be reconstruct2022-01-01T00:00:00Z20222025-07-13T03:04:14.5Z2025-04-21T14:36:25.875ZS-EPMC97039903645208010.7717/peerj.14461