Data from: Computed tomographic analysis of dental system of three Jurassic ceratopsians: implications for the evolution of the tooth replacement pattern and diet in early-diverging ceratopsians

The dental system of ceratopsids is among the most specialized structure
in Dinosauria, and includes high angled wear surfaces, split tooth roots,
and multiple teeth in each tooth family. However, the early evolution of
this unique dental system is generally poorly understood due to a lack of
knowledge of the dental morphology and development in early-diverging
ceratopsians. Here we study the dental system of three of the
earliest-diverging Chinese ceratopsians: Yinlong and Hualianceratops from
the early Late Jurassic of Xinjiang, and Chaoyangsaurus from the Late
Jurassic of Liaoning. By using micro-computed tomographic analyses, our
study has revealed significant new information regarding the dental system
of these early ceratopsians, including no more than five replacement teeth
in each jaw quadrant; at most one generation of replacement teeth in each
alveolus; nearly full resorption of the functional tooth root during tooth
replacement; and occlusion with low-angled, concave wear facets that
differs significantly from the shearing occlusal system seen in
ceratopsids. Yinlong displays an increase in the number of maxillary tooth
alveoli and a decrease in the number of replacement teeth during ontogeny
as well as the retention of remnants of functional teeth in the largest
individual. Early-diverging ceratopsians thus display a relatively slow
tooth replacement rate compared to late-diverging ceratopsians. Combined
with paleobotany and palaeoenvironment data, Yinlong likely uses
gastroliths to triturate foodstuffs, and the difference in diet strategy
might have influenced the pattern of tooth replacement in later-diverging
ceratopsians.