Skeletal and dental development of larval batrachians: The influence of developmental processes on the evolution of novelties and the evolution of neobatrachian diversity.

软骨或骨性头骨是脊椎动物的中心创新。它的结构非常复杂，其功能范围从保护大脑和重要的感官器官到有效的食物摄入。在个体发育过程中，头骨最初是由软骨建造的。与骨骼不同，软骨可以发育得更快，能量摄入更少，这有利于它的早期出现。在进一步的发育过程中，软骨前体骨架主要被骨取代。蝌蚪阶段是无尾两栖动物多样化的核心。幼虫和成虫在生理、形态和生态上的分离使水生和陆地生境得以有效地独立开发。无尾两栖类蝌蚪可以通过其球形的身体和长而肌肉发达的尾巴来区别于成年青蛙。除了这些特征外，蝌蚪的嘴部区域对它们的成功和多样性至关重要。口腔周围环绕着一个口腔盘。它通常由上唇和下唇组成。两者都被一排或多排角化结构所包围，这些结构被称为唇齿。这个项目将比较蝙蝠脊椎动物的骨骼发育和无尾两栖动物唇齿的发育。采用组织学、免疫组织化学和微区扫描等方法，对无尾两栖类和尾类的骨骼发育进行了分析和描述。利用异时图、基于Parsimov的遗传推理和解剖网络分析进行序列比较，将为了解各自发育序列的异时变化和发育中头骨的模块化以及重建祖先发育序列提供洞察力。将确定任何发育变化，并定义不同类群的骨骼发育特征。他们还将与其他脊椎动物的骨骼发育特征进行比较。以往的研究结果表明，无尾两栖动物幼虫骨骼发育的顺序与其他脊椎动物不同。与尾龙幼虫的比较将提供信息，这是否是独有的蝙蝠纲特征，以及如何对尾龙的骨骼发育进行分类。利用扫描电子显微镜、透射电子显微镜和组织学在细胞水平上对不同无尾两栖动物唇齿的发育进行研究和描述。该项目的成果之一将是对这一结构的发展进行第一次详细描述。总体而言，该项目将增加我们对无尾轮虫幼虫发育的了解，并提高我们对骨骼发育进化机制的理解。

The cartilaginous or bony skull is the central innovation of vertebrates. Its structure is highly complex, and its functions range from protecting the brain and important sensory organs to enabling effective food intake. During ontogeny, the skull is initially built from cartilage. Unlike bone, cartilage can develop more quickly and with less energy intake, which favours its early appearance. The cartilaginous precursor skeleton is predominantly replaced by bone during further development. The tadpole stage is central to the diversification of the anura. The separation of larvae and adults in terms of physiology, morphology and ecology allows aquatic and terrestrial habitats to be effectively exploited independently. Anuran tadpoles can be distinguished from adult frogs by their spherical bodies and long, muscular tails. In addition to these features, the mouth region of the tadpoles is crucial for their success and diversity. The mouth is surrounded by an oral disc. It typically consists of an upper and lower lip. Both are surrounded by one or more rows of keratinized structures called labial teeth. This project will compare the skeletal development of Batrachia and the development of the anuran labial teeth. Using histology, immunohistochemistry, clearing and staining and µ-CT, the skeletal development of different Anura and Urodela will be analysed and described. Comparison of sequences using heterochrony plot, Parsimov-based Genetic inference and Anatomical Network Analysis will provide insights on heterochronic shifts in the respective developmental sequences and the modularity of the developing skull, as well as reconstructing the ancestral developmental sequences. Any developmental changes will be identified and characteristics of skeletal development of different taxa will be defined. They will also be compared with the characteristics of skeletal development in other vertebrates. Previous results have shown, that the sequence of skeletal development in anuran larvae differs from that in other vertebrates. A comparison with urodelan larvae will provide information on whether this is an exclusive batrachian feature and how the skeletal development of Urodela should be classified. The development of the labial teeth of different anurans will be investigated and described at the cellular level using scanning electron microscopy, transmission electron microscopy and histology. One result of the project will be the first detailed description of the development of this structure. Overall, the project will increase our knowledge on the development of batrachian larvae and improve our understanding of the mechanisms underlying the evolution of skeletal development.