What anatomical finding indicated that Xenoceratops was considered a large herbivore when considering its size within the Centrosaurine radiation?

It is generally recognized as a large centrosaurine, typical of the larger members of the ceratopsian radiation.

The assessment of Xenoceratops's size places it generally within the classification of a large centrosaurine. This designation implies that it was a substantial herbivore, consistent with the larger forms within the overall ceratopsian evolutionary radiation. This large bulk was an important ecological factor, affording it natural protection against smaller predatory threats and suggesting that its diet, while consisting of tough vegetation like ferns and cycads processed by its powerful beak, required a large digestive capacity characteristic of big herbivores of the Late Cretaceous period.