小柯机器人

瑞典乌普萨拉大学Per Erik Ahlberg、Valéria Vaškaninová研究团队合作取得新进展。他们发现颌骨脊椎动物的祖先具有边缘齿列和多个真皮颚骨的特征。2020年7月10日出版的《科学》杂志发表了这项成果。

他们用同步加速器显微照相技术描述了所谓的棘索酸的化石牙列，这是系统发育最基础的有牙齿的基颚脊椎动物，属于Radotina、Kosoraspis和Tlamaspis属（来自捷克共和国早期泥盆纪）。他们的牙列与节肢动物根本不同。它们靠边缘，由脸颊骨或沿着颌骨边缘的一系列短皮骨托着，并且像许多软骨鱼类（软骨鱼类）和锁骨鱼类（黑骨鱼类和四足动物）一样，舌侧添有牙齿。他们提出这些特征是所有颌骨脊椎动物的祖先具有的。

据了解，现存鱼类和陆地脊椎动物的牙列在牙齿替换的模式和类型上都不同。有人认为，共同的祖先很可能具有类似于节肢动物的非边缘、放射状排列的牙锉，节肢动物是早期的装甲鱼类。

附：英文原文

Title: Marginal dentition and multiple dermal jawbones as the ancestral condition of jawed vertebrates

Author: Valéria Vakaninová, Donglei Chen, Paul Tafforeau, Zerina Johanson, Boris Ekrt, Henning Blom, Per Erik Ahlberg

Issue&Volume: 2020/07/10

Abstract: 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 Radotina, Kosoraspis, and Tlamaspis (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.

DOI: 10.1126/science.aaz9431

Source: https://science.sciencemag.org/content/369/6500/211