Eucaridan evolution involved a process starting from a body organization characterized by an elongate and cylindrical cephalothorax, a well-developed abdomen composed of swimming appendages, ending in a tail fan formed by flattened uropods and a telson. This process would lead, ultimately, to a body organization characterized by a shortened and depressed cephalothorax, and a reduced and ventrally folded abdomen. This ultimate process is typically known as carcinization, and is commonly defined as the process of becoming a crab. In this work, the evolution of the superorder Eucarida was studied using complex networks. A new definition of crab and carcinization are given based on the results obtained. A crab is a topological structural closure that determines the formation of a triadic central core. The evolution of the crab implied the formation of a triadic structure with high closeness centrality, formed by the cephalon, the fused thoracomere 1–4 and the carapace, which represented a highly stable hierarchical core deeply buried or enclosed in the topological structure of the network, responsible for the generation of a highly integrated and robust topology. Under this new definition, the representative of the infraorder Anomura used in this work, which is commonly considered as a crab, is not. This network seemed to be characterized by the presence of a quasi-dyadic structure, formed by the cephalon and the carapace, which was not sufficient for generating the topological closure.

中文翻译：

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做螃蟹是什么感觉？桉树进化的复杂网络分析

桉树的进化涉及一个过程，该过程始于以长而圆柱形的头胸部为特征的身体组织，后者是由游泳附件组成的发达的腹部，最后被扁平的尾足和尾巴形成尾扇。这个过程最终将导致身体组织的特征是头胸部胸廓缩短和凹陷，腹部腹部缩小和折叠。此最终过程通常称为致癌作用，通常定义为变成螃蟹的过程。在这项工作中，使用复杂网络研究了超阶Eucarida的进化。根据获得的结果，给出了螃蟹和致癌作用的新定义。螃蟹是一种拓扑结构的闭合结构，它决定了三叠纪中央核的形成。螃蟹的进化意味着由头颅，融合的胸腺1-4和甲壳形成的具有高度紧密中心性的三叠纪结构的形成，它们代表了一个高度稳定的层次核心，被深埋或封闭在网络的拓扑结构中，负责生成高度集成且强大的拓扑。在这个新定义下，这项工作中使用的红外野村的代表（通常被认为是螃蟹）不是。该网络的特征似乎在于存在由头颅和甲壳形成的准二进位结构，这不足以产生拓扑封闭。它代表了一个高度稳定的分层核心，该核心被深深地掩埋或封装在网络的拓扑结构中，负责生成高度集成且健壮的拓扑。在这个新定义下，这项工作中使用的红外野村的代表（通常被认为是螃蟹）不是。该网络的特征似乎是由头颅和甲壳形成的准二进位结构的存在，不足以产生拓扑封闭。它代表了一个高度稳定的分层核心，该核心被深深地掩埋或封装在网络的拓扑结构中，负责生成高度集成且健壮的拓扑。在这个新定义下，这项工作中使用的红外野村的代表（通常被认为是螃蟹）不是。该网络的特征似乎在于存在由头颅和甲壳形成的准二进位结构，这不足以产生拓扑封闭。