Genus: Iguanacolossus McDONALD, KIRKLAND, DeBLIEUX, MADSEN, CAVIN, MILNER & PANZARIN, 2010
Etymology: Iguana, and Latin, colossus, in reference to the herbivorous lizards of the genus Iguana, the teeth of which have been historically compared to those of basal iguandonts, and the large size of the holotype.

Species: fortis McDONALD, KIRKLAND, DeBLIEUX, MADSEN, CAVIN, MILNER & PANZARIN, 2010
Etymology: Latin, fortis, "mighty."

Holotype: UMNH VP 20205

Locality: Don's Ridge, UMNH VP locality 1206, near Green River, Grand County, Utah.
Note: Exact locality information is on the file at the Utah Geological Survey and Utah Museum of Natural History.

Horizon: Yellow Cat Member, Cedar Mountain Formation.

Biostratigraphy:

Age: Barremian Stage, Lower Gallic Subepoch, Middle Early Cretaceous Epoch, Upper Early Cretaceous.

Material: An associated partial skeleton of a single individual.