Brink Kirstin S, Chen Yu-Cheng, Wu Ya-Na, Liu Wei-Min, Shieh Dar-Bin, Huang Timothy D, Sun Chi-Kuang, Reisz Robert R
Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada L5 L 1C6
Molecular Imaging Center, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
J R Soc Interface. 2016 Dec;13(125). doi: 10.1098/rsif.2016.0626.
Teeth are key to understanding the feeding ecology of both extant and extinct vertebrates. Recent studies have highlighted the previously unrecognized complexity of dinosaur dentitions and how specific tooth tissues and tooth shapes differ between taxa with different diets. However, it is unknown how the ultrastructure of these tooth tissues contributes to the differences in feeding style between taxa. In this study, we use third harmonic generation microscopy and scanning electron microscopy to examine the ultrastructure of the dentine in herbivorous and carnivorous dinosaurs to understand how the structure of this tissue contributes to the overall utility of the tooth. Morphometric analyses of dentinal tubule diameter, density and branching rates reveal a strong signal for dietary preferences, with herbivorous saurischian and ornithischian dinosaurs consistently having higher dentinal tubule density than their carnivorous relatives. We hypothesize that this relates to the hardness of the dentine, where herbivorous taxa have dentine that is more resistant to breakage and wear at the dentine-enamel junction than carnivorous taxa. This study advocates the detailed study of dentine and the use of advanced microscopy techniques to understand the evolution of dentition and feeding ecology in extinct vertebrates.
牙齿是了解现存和已灭绝脊椎动物进食生态学的关键。最近的研究强调了恐龙牙列此前未被认识到的复杂性，以及不同食性类群之间特定牙齿组织和牙齿形状的差异。然而，这些牙齿组织的超微结构如何导致不同类群进食方式的差异尚不清楚。在本研究中，我们使用三次谐波产生显微镜和扫描电子显微镜来检查草食性和肉食性恐龙牙本质的超微结构，以了解该组织的结构如何影响牙齿的整体功能。对牙本质小管直径、密度和分支率的形态计量分析揭示了饮食偏好的强烈信号，草食性蜥臀目和鸟臀目恐龙的牙本质小管密度始终高于它们的肉食性近亲。我们推测这与牙本质的硬度有关，草食性类群的牙本质在牙本质 - 釉质交界处比肉食性类群更能抵抗破损和磨损。本研究提倡对牙本质进行详细研究，并使用先进的显微镜技术来了解已灭绝脊椎动物牙列和进食生态学的进化。
