The paleogeographic and stratigraphic distribution of ceratopsids (Ornithischia) in the upper Judith River Group of Western Canada

Royal Tyrrell Museum of Palaeontology, Drumheller, AB, Canada

Articulated remains and teeth preserved in vertebrate microfossil localities are used as independent lines of evidence to quantify the relative abundances of dinosaurs along a 250-km transect extending from the paleogeographically more inland Dinosaur Provincial Park area (Alberta), through the South Saskatchewan River area, to the more coastal Unity, Saskatchewan locality. A comparison of articulated dinosaur remains along chronostratigraphically equivalent horizons from the Dinosaur Provincial Park and South Saskatchewan areas indicate that ceratopsid dinosaurs are more abundant in the South Saskatchewan River area, whereas the converse is true for ankylosaur and pachycephalosaur dinosaurs. In the case of ceratopsid dinosaurs, the same distributional pattern is reflected in data amassed from vertebrate microfossil assemblages from these areas. In addition, vertebrate microfossil assemblages show that ceratopsids increase in relative abundance moving upsection in both the Dinosaur Park and South Saskatchewan River areas. In these same sections ankylosaurs and pachycephalosaurs decrease in abundance in the Dinosaur Park area, but their abundances show no change up through the section in the South Saskatchewan River area. These paleogeographic and stratigraphic patterns further support the existing hypothesis that ceratopsids were relatively more abundant in coastal areas, rather than inland areas, during the Campanian. They also provide tentative support for the hypothesis that ankylosaurs and pachycephalosaurs were, in general, more prominent members of inland communities.

This record provided courtesy of AGI/GeoRef.