PaleoDB taxon number: 55251
Full reference: L. J. Hickey. 1977. Stratigraphy and paleobotany of the Golden Valley Formation (Early Tertiary) of western North Dakota. The Geological Society of America Memoir 150:1-183
Type specimen: PU 20091. Its type locality is North of Gladstone (USNM 14083), which is in a Clarkforkian channel siltstone/sandstone in the Golden Valley Formation of North Dakota.