PaleoDB taxon number: 55230
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: USNM 43744. Its type locality is Otter Creek (USNM 14066a), which is in a Clarkforkian channel shale in the Golden Valley Formation of North Dakota.