Department of Organismal Biology, Uppsala University, Norbyvägen 18A, SE-752 36, Uppsala, Sweden.
Institute of Geology and Palaeontology, Faculty of Science, Charles University, Albertov 6, Prague, 12843, Czech Republic.
Science. 2020 Jul 10;369(6500):211-216. doi: 10.1126/science.aaz9431.
The dentitions of extant fishes and land vertebrates vary in both pattern and type of tooth replacement. It has been argued that the common ancestral condition likely resembles the nonmarginal, radially arranged tooth files of arthrodires, an early group of armoured fishes. We used synchrotron microtomography to describe the fossil dentitions of so-called acanthothoracids, the most phylogenetically basal jawed vertebrates with teeth, belonging to the genera , , and (from the Early Devonian of the Czech Republic). Their dentitions differ fundamentally from those of arthrodires; they are marginal, carried by a cheekbone or a series of short dermal bones along the jaw edges, and teeth are added lingually as is the case in many chondrichthyans (cartilaginous fishes) and osteichthyans (bony fishes and tetrapods). We propose these characteristics as ancestral for all jawed vertebrates.
现存鱼类和陆地脊椎动物的牙齿在形态和换牙类型上都有所不同。有人认为，共同的祖先可能类似于早期有甲鱼类的非边缘、放射状排列的牙齿锉，有甲鱼类是一种有甲的鱼类。我们使用同步加速器微断层扫描来描述所谓的棘胸鱼目（有颌脊椎动物中最基础的一类，有牙齿）的化石牙齿，其代表属有 、 和 （来自捷克共和国的早泥盆世）。它们的牙齿与有甲鱼类的牙齿有根本的不同；它们是边缘的，由颧骨或一系列沿颚缘的短真皮骨携带，牙齿像许多软骨鱼类（软骨鱼）和硬骨鱼类（硬骨鱼和四足动物）一样向舌侧添加。我们提出这些特征是所有有颌脊椎动物的祖先特征。
