The Canadian fossil record supports anagenesis in Triceratops (Ornithischia, Ceratopsia)

This is the authors' abstract. We don't add key points for this paper.

Evolution of the ceratopsid dinosaur Triceratops has been hypothesized to have proceeded anagenetically, with the geologically older Triceratops horridus Marsh, 1889 having directly given rise to the younger Triceratops prorsus Marsh, 1890. This evolutionary scenario is based primarily on the upper Maastrichtian fossil record of the Hell Creek Formation in Montana. The Canadian fossil record affords an opportunity to test this hypothesis beyond the geographic bounds where it was originally developed. The Canadian strata (lower Scollard Formation of Alberta and Frenchman Formation of Saskatchewan) are roughly contemporaneous with the upper third of the Hell Creek Formation where Triceratops prorsus is found. On the anagenesis hypothesis, the Canadian strata should, therefore, uniquely contain that species. Our exhaustive survey of the Canadian Triceratops material, supported by cladistic and ordination analyses, confirms the presence of a single species, Triceratops prorsus, in Canada, yielding robust support for the anagenesis hypothesis conceived for the genus.