Vertebrate palaeoichnology of the lower cretaceous (lower Albian) gates formation of Alberta
McCrea, Richard T.
Western Canada has few significant skeletal remains of terrestrial vertebrates from the Lower Cretaceous. The only substantial record of Early Cretaceous terrestrial vertebrates comes from footprints. The Grande Cache Member of the Gates Formation, on the coal lease property of Smoky River Coal Limited in western Alberta, exhibits abundant footprint traces of vertebrates from the Lower Cretaceous (Albian). The vertebrate ichnofauna described herein (Smoky River ichnofauna) includes footprints of dinosaurs (theropods, ?ornithopods and thyreophorans), birds and mammals. The Smoky River ichnofauna consists of eight ichnospecies assigned to seven ichnogenera. Two new ichnospecies, Aquatilavipes ichnosp. nov., and ?Tricorynopus ichnosp. nov., are described and the definitions of the ichnotaxa Irenesauripus mclearni, Columbosauripus ungulatus, Gypsichnites pacensis, Irenichnites gracilis, Tetrapodosaurus borealis, Aquatilavipes and Fuseinapeda are emended. Previous perceptions of the Lower Cretaceous terrestrial vertebrates from Canada came from the studies of the ornithopod-theropod dominated Peace River Ichnofauna from British Columbia. Large-scale tracksites from the Gates Formation within the Smoky River Coal Mine dominated by the footprints of ankylosaurs has shed new light on the composition of Lower Cretaceous vertebrate ichnofaunas. The distribution of ichnotaxa at these tracksites may indicate habitat preference for some of the track-makers, possibly controlled by the energy of the depositional environments and presence of vegetation.