DEWEY COUNTY

HELL CREEK FORMATION

LANCIAN AGE

UPPER MAASTRICHTIAN STAGE

UPPERMOST SENONIAN SUBEPOCH

UPPER GULF EPOCH

LATE CRETACEOUS

STEM: TETRAPODA GOODRICH, 1930

SUPERCLASS: AMNIOTA HAECKEL, 1866

CLASS: REPTILIA LAURENTI, 1768

SUBCLASS: DIAPSIDA OSBORN, 1903

SUPERLEGION: NEODIAPSIDA BENTON, 1985

LEGION: ARCHOSAUROMORPHA HUENE, 1946

SUBLEGION: DINOSAUROMORPHA BENTON & NORMAN IN BENTON, 1985

INFRALEGION: DINOSAURIFORMES NOVAS, 1992

SUPERCOHORT: DINOSAURIA OWEN, 1842

COHORT: ORNITHISCHIFORMES COOPER, 1985

MAGNORDER: ORNITHISCHIA SEELEY, 1888

SUPERORDER: NEORNITHISCHIA COOPER, 1985

GRANDORDER: ORNITHOPODA MARSH, 1871

MICRORDER: EUORNITHOPODA SERENO, 1986

ORDER: IGUANODONTIA DOLLO, 1888

Family: THESCELOSAURIDAE Sternberg, 1937

Thescelosaurus neglectus

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