Development of the circulatory system in Crustacea - Testing potential homologies between arthropods and annelids

作为一种潜在的环节动物和节肢动物的突触形态，分割在关节动物和外翻动物的争论中起着核心作用。然而，分割并不构成数据矩阵中的单个字符，而是一组高度复杂的特征，其中循环系统的发展是主要组成部分之一。在环节动物中，血管出现在发育中的体腔腔的上皮之间，但在真节肢动物中发生的情况更不确定，因为假定的体腔腔会发生转化、分裂和减少。在该项目的第一阶段，将研究三种甲壳类典型物种（口足类、片足类和十足类）循环系统的发育。与其他节肢动物相比，口足动物的循环系统具有最高的同源性，特别适合与环节动物进行比较。之所以选择两足动物和十足动物的代表，是因为它们的文化和研究方法已经很成熟。基于连续切片、透射电子显微镜、Micro-CT、共聚焦激光扫描显微镜显示的单细胞标记，最后使用最新软件进行三维重建，将进行迄今为止最详细的循环系统发展研究，为与环节动物循环系统发展进行更深入的比较提供基础。节肢动物和环节动物在成体解剖和发育上的详细相似性可以为分割的同源性提供支持，而大量的差异可能会削弱同源性的可能性

As a potential synapomorphy of Annelida and Arthropoda ¿segmentation¿ plays a central role in the current controversy Articulata versus Ecdysozoa. However, segmentation does not constitute a single character in a data matrix but a highly complex set of features, where the development of the circulatory system is one of the major components. Whereas in annelids, blood vessels appear between the epithelia of the developing coelomic cavities, it is more uncertain what occurs in euarthropods because putative ¿coelomic¿ cavities become transformed, divided and reduced. During the first phase of this project, the development of the circulatory system in three exemplar species of Crustacea ¿ representatives of Stomatopoda, Amphipoda and Decapoda ¿ will be studied. Stomatopoda possess the circulatory system with the highest degree of homonomy in comparison to all other arthropods and are in particular suited for a comparison with annelids. The representatives of Amphipoda and Decapoda are chosen because of already well established cultures and methodology. Based on serial sections, transmission-electron-microscopy, Micro-CT, single cell labelling visualised by confocal laser-scanning-microscopy, and finally 3D reconstruction using up-to-date software, the most detailed study of the development of the circulatory system to date will be carried out, providing the basis for a more substantial comparison with the development of the circulatory system in annelids. Detailed similarities between arthropods and annelids in both adult anatomy and development could provide support for the homology of segmentation, whereas a large number of differences might weaken the probability of homology.3