研究人员发现，下寒武统叶足动物Cardiodictyon catenulum的神经系统化石提供了澄清，该化石显示了一个没有分节的头部和大脑，包括三个头区，与服务于其附属躯干的体节神经系统不同。每个区与前肠的三个组成部分之一和一对头部附属物相一致。与干群节肢动物的形态学对应，以及与现存泛节肢动物的同源基因表达模式的并列，表明C. catenulum的头区早于真节肢动物头部的演化，但与定义现存螯肢动物和有颚动物大脑的神经元对应。
据悉，一个多世纪以来，节肢动物头部和大脑的起源和演化一直没有一个统一的理由来调和不同的形态和系统发育关系。
附：英文原文
Title: The lower Cambrian lobopodian Cardiodictyon resolves the origin of euarthropod brains
Author: Nicholas J. Strausfeld, Xianguang Hou, Marcel E. Sayre, Frank Hirth
Issue&Volume: 2022-11-25
Abstract: For more than a century, the origin and evolution of the arthropod head and brain have eluded a unifying rationale reconciling divergent morphologies and phylogenetic relationships. Here, clarification is provided by the fossilized nervous system of the lower Cambrian lobopodian Cardiodictyon catenulum, which reveals an unsegmented head and brain comprising three cephalic domains, distinct from the metameric ventral nervous system serving its appendicular trunk. Each domain aligns with one of three components of the foregut and with a pair of head appendages. Morphological correspondences with stem group arthropods and alignments of homologous gene expression patterns with those of extant panarthropods demonstrate that cephalic domains of C. catenulum predate the evolution of the euarthropod head yet correspond to neuromeres defining brains of living chelicerates and mandibulates.
DOI: abn6264
Source: https://www.science.org/doi/10.1126/science.abn6264