School of Earth Sciences, China University of Geosciences, Wuhan, China.
Department of Biological Sciences, The George Washington University, Washington, United States.
Elife. 2022 Apr 20;11:e76676. doi: 10.7554/eLife.76676.
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: and from the early Late Jurassic of Xinjiang and 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 functional tooth root; and occlusion with low-angled, concave wear facets. displays an increase in the number of maxillary alveoli and a decrease in the number of replacement teeth during ontogeny as well as the retention of functional tooth remnants in the largest individual. and have slightly more replacement teeth than . In general, early-diverging ceratopsians display a relatively slow tooth replacement rate and likely use gastroliths to triturate foodstuffs. The difference in dietary strategy might have influenced the tooth replacement pattern in later-diverging ceratopsians.
角龙类的牙齿系统是恐龙中最具特化结构的之一，其特征为齿列和高角度磨损面的存在。然而，由于早期角龙类相关知识的缺乏，这种独特的牙齿系统的起源仍不清楚。在这里，我们研究了三种最早分化的中国角龙类的牙齿系统：来自新疆早白垩世晚期的和来自辽宁晚侏罗世的 。通过微计算机断层扫描分析，我们的研究揭示了关于牙齿系统的重要新信息，包括每侧颌骨象限中不超过五颗替换牙；每个牙槽中最多一颗替换牙；功能性牙齿根几乎完全吸收；以及低角度、凹面的咬合。显示出在个体发育过程中，上颌牙槽数量增加和替换牙数量减少，以及最大个体中保留功能性牙齿残余物的趋势。和 比 有更多的替换牙。一般来说，早期分化的角龙类显示出相对较慢的牙齿替换率，并可能使用胃石来研磨食物。不同的饮食策略可能影响了后来分化的角龙类的牙齿替换模式。
