Abstract

Developing morphological diagnoses for fossil mammals requires an understanding of intraspecific variation in the anatomical elements under study. Dental traits along with tooth size can be informative of taxonomic identify for extinct species. However, it is unclear what selective or developmental processes are responsible for documented patterns in tooth-size variation making application to the fossil record difficult. We assessed combined species tooth-type variation and intraspecific tooth-size variation for 19 species to evaluate whether developmental controls or occlusion-driven functional demands influence carnivoran tooth-size variation. We also estimated phylogenetic signal for the coefficient of variation (CV). Combined species tooth-size variation separated by tooth type shows that canines are more variable than molars and lower premolars. We found intraspecific tooth-size variation patterns differ between species. However, comparisons of the CVs did not support the hypotheses that developmental controls or functional demands of occlusion constrain size variation in mammal teeth. Our results suggest that a combination of factors influence carnivoran tooth-size variation, such as differences in ontogeny, diet, sexual dimorphism, and evolutionary history. Patterns of carnivoran intraspecific tooth-size variation suggest a better understanding of dental size variation in extant species is essential for accurate morphological studies of fossil taxa.

中文翻译：

---

食肉动物种内牙齿的大小变化显示出沿齿排和种间的异质性

摘要

对化石哺乳动物进行形态学诊断需要了解正在研究的解剖元素的种内变异。牙齿特征以及牙齿大小可以为灭绝物种的分类学鉴定提供信息。但是，尚不清楚什么选择性或发育过程导致牙齿大小变化的已记录模式，从而难以应用于化石记录。我们评估了19种物种的组合物种牙齿类型变异和种内牙齿尺寸变异，以评估发育控制或咬合驱动的功能需求是否影响食肉动物牙齿尺寸变异。我们还估计了变异系数（CV）的系统发育信号。通过牙齿类型分开的组合物种牙齿大小变化表明，犬齿比磨牙和较低的前磨牙具有更大的可变性。我们发现种内的种内牙齿大小变异模式有所不同。但是，CV的比较不支持这样的假设，即发育控制或闭塞的功能需求会限制哺乳动物牙齿的大小变化。我们的结果表明，多种因素共同影响食肉动物牙齿的大小变异，例如个体发育，饮食，性二态性和进化史的差异。食肉动物种内牙齿大小变化的模式表明，对现存物种牙齿大小变化的更好理解对于化石分类群的准确形态学研究至关重要。CV的比较不支持这样的假说，即发育控制或闭塞的功能需求会限制哺乳动物牙齿的大小变化。我们的结果表明，多种因素共同影响食肉动物牙齿的大小变异，例如个体发育，饮食，性二态性和进化史的差异。食肉动物种内牙齿大小变化的模式表明，对现存物种牙齿大小变化的更好理解对于化石分类群的准确形态学研究至关重要。CV的比较不支持这样的假说，即发育控制或闭塞的功能需求会限制哺乳动物牙齿的大小变化。我们的结果表明，多种因素共同影响食肉动物牙齿的大小变异，例如个体发育，饮食，性二态性和进化史的差异。食肉动物种内牙齿大小变化的模式表明，对现存物种牙齿大小变化的更好理解对于化石分类群的准确形态学研究至关重要。