Reptilian Tooth and Jaw Development

爬行动物和哺乳动物有着共同的祖先，可以追溯到3亿多年前，但在进化过程中，头骨和牙齿出现了显著的专业化。我们的目标是确定这些差异在开发过程中是如何以及何时出现的。例如，大多数爬行动物的头骨比哺乳动物的头骨有更多的开口。哺乳动物总是闭合着上颚，将口腔和鼻腔分开。相比之下，蛇、蜥蜴和鸟类的味觉是开放的，海龟的味觉是原始的，令人惊讶的是，鳄鱼的味觉像哺乳动物一样闭合。在牙列中，牙齿解剖和替换能力也有明显差异。大多数蛇、蜥蜴和鳄鱼在一生中不断地更换牙齿(多齿类)，而哺乳动物只能更换一次牙齿。

Reptiles and mammals share a common ancestor dating back more than 300 million years but during evolution significant specializations in the skull and teeth have arisen. Our goal is to determine how and when in development these differences arose. For example, skulls of the majority of reptiles have more openings than mammals. Mammals always have closed palates that separate the oral and nasal cavities. In contrast snakes, lizards and birds have open palates, turtles have a primitive palate and surprisingly alligators have a closed palate like mammals. In the dentition, there are also striking differences in tooth anatomy and replacement capacity. Most snakes, lizards and crocodilians replace their teeth continuously throughout life (polyphyodonty), whereas mammals can only replace their teeth once.