Ceratopsid tracks and associated ichnofauna from the Laramie Formation (Upper Cretaceous: Maastrichtian) of Colorado

ABSTRACT

The Laramie Formation (Upper Cretaceous: Maastrichtian) contains multiple trackbearing horizons exhibiting a diverse assemblage of ceratopsid, ornithopod and theropod tracks and trackways. The ceratopsid tracks are the first attributable to this family and we describe them as a new ichnotaxon, Ceratopsipes goldenensis, ichnogen. et ichnosp. nov. These tracks indicate that models of forelimb posture of ceratopsids that postulated a sprawling stance are incorrect. The ceratopsid-dom-inated ichnofauna reflects the body fossil record of the Laramie Formation. Theropod tracks indicate a diverse fauna including an ichnite that possibly represents Tyrannosaurus. A partial trackway represents the first reported champsosaur ichnites herein named Champsosaurichnus parfeti ichnogen. et ichnosp. nov. The ichnofauna also includes hadrosaur tracks and is useful in reconstructing the animal communities that inhabited the area.