Synchrotron radiation X-ray microdiffraction (SR-μXRD) has been applied for the first time as a fundamental method of analysis to unveil crocodilian teeth growth and development. Teeth from a fossil crocodylomorph from the Upper Cretaceous site of Lo Hueco (Spain) and a modern crocodylian from the living species Crocodylus niloticus have been analysed. Both samples have been studied through Polarized Light Microscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy, Confocal Raman Spectroscopy, and SR-μXRD. Significant differences have been found in hydroxyapatite (HA) crystallite sizes and texture, and the evolution of these two features along teeth depth. The main differences observed in crystallite size are related to postdepositional processes and/or the environmental and functional pressures of teeth during crocodylomorph life, very different from that of the modern specimen. Regarding the crystalline texture in the tooth enamel, it can be linked to teeth functionality during crocodilian life, causing the directed growth of HA crystallites due to the mechanical stress to which they are subjected.

同步辐射 X 射线微衍射 (SR-μXRD) 首次被用作揭示鳄鱼牙齿生长和发育的基本分析方法。来自 Lo Hueco（西班牙）上白垩纪遗址的鳄鱼化石化石和来自现存物种Crocodylus niloticus的现代鳄鱼的牙齿进行了分析。两种样品都通过偏振光显微镜、扫描电子显微镜与能量色散 X 射线光谱、共焦拉曼光谱和 SR-μXRD 进行了研究。在羟基磷灰石 (HA) 微晶尺寸和质地以及这两个特征沿牙齿深度的演变中发现了显着差异。观察到的微晶尺寸的主要差异与鳄鱼形生命期间牙齿的沉积后过程和/或环境和功能压力有关，与现代标本的非常不同。关于牙釉质中的结晶质地，它可能与鳄鱼生活中的牙齿功能有关，由于它们受到的机械应力，导致 HA 微晶的定向生长。