biostudies-literatureHu JNational Natural Science Foundation of ChinaInternational Partnership Program of Chinese Academy of Sciencese76676https://www.ebi.ac.uk/biostudies/studies/S-EPMC9068210biostudies-literatureUnknown11The dental system of ceratopsids is among the most specialized structure in Dinosauria by the presence of tooth batteries and high-angled wear surfaces. However, the origin of this unique dental system is poorly understood due to a lack of relevant knowledge in early-diverging ceratopsians. Here, we study the dental system of three earliest-diverging Chinese ceratopsians: <i>Yinlong</i> and <i>Hualianceratops</i> from the early Late Jurassic of Xinjiang and <i>Chaoyangsaurus</i> from the Late Jurassic of Liaoning Province. By micro-computed tomographic analyses, our study has revealed significant new information regarding the dental system, including no more than five replacement teeth in each jaw quadrant; at most one replacement tooth in each alveolus; nearly full resorption of the functeLifeComputed tomographic analysis of the dental system of three Jurassic ceratopsians and implications for the evolution of tooth replacement pattern and diet in early-diverging ceratopsians.PMC906821042072008132311KYSB2018001642288201 and 4168810341972021He YHu JZhao QXu XForster CAHan FfalseComputed tomographic analysis of the dental system of three Jurassic ceratopsians and implications for the evolution of tooth replacement pattern and diet in early-diverging ceratopsians.The dental system of ceratopsids is among the most specialized structure in Dinosauria by the presence of tooth batteries and high-angled wear surfaces. However, the origin of this unique dental system is poorly understood due to a lack of relevant knowledge in early-diverging ceratopsians. Here, we study the dental system of three earliest-diverging Chinese ceratopsians: <i>Yinlong</i> and <i>Hualianceratops</i> from the early Late Jurassic of Xinjiang and <i>Chaoyangsaurus</i> from the Late Jurassic of Liaoning Province. By micro-computed tomographic analyses, our study has revealed significant new information regarding the dental system, including no more than five replacement teeth in each jaw quadrant; at most one replacement tooth in each alveolus; nearly full resorption of the funct2022-01-01T00:00:00Z2022 Apr2026-05-09T21:49:03.817Z2025-04-04T10:01:43.846ZS-EPMC90682103544159210.7554/eLife.76676