Unlocking the early fossil record of the arthropod central nervous system.
Unlocking the early fossil record of the arthropod central nervous system.
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解锁节肢动物中枢神经系统的早期化石记录。
DOI：
10.1098/rstb.2015.0038
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发表时间：
2015-12-19
期刊：
影响因子：
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通讯作者：
Strausfeld NJ
中科院分区：
文献类型：
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作者：
Edgecombe GD;Ma X;Strausfeld NJ
现存的泛节肢动物（真节肢动物，onychophorans和缓步动物）的特点是惊人的形态和分类多样性，但他们的中枢神经系统（CNS）是相对保守的。分歧的时间的地面模式中枢神经系统组织的主要泛节肢动物分支一直受到很大的限制，因为缺乏数据，从他们的早期化石记录。虽然CNS在新生代琥珀中的昆虫中已经有了三维的详细记录，但人们普遍认为这些组织太容易腐烂，无法承受其他类型的石化或地质上更古老的保存。然而，寒武纪伯吉斯页岩型挤压已经成为大脑和神经索的来源。这些寒武纪化石中的CNS以碳膜或黄铁矿与碳结合后的铁氧化物/氢氧化物的形式保存下来。在细粒沉积物中压实的尸体实验描绘了比在其他介质中进行的衰变实验预期的更长时间窗口的神经组织保存。异常保存寒武纪化石中的CNS和复眼特征预测了寒武纪第3阶段（约518 Ma）的下颌骨和螯形骨地面模式的分歧，这与这些分裂的分子估计是兼容的。
Extant panarthropods (euarthropods, onychophorans and tardigrades) are hallmarked by stunning morphological and taxonomic diversity, but their central nervous systems (CNS) are relatively conserved. The timing of divergences of the ground pattern CNS organization of the major panarthropod clades has been poorly constrained because of a scarcity of data from their early fossil record. Although the CNS has been documented in three-dimensional detail in insects from Cenozoic ambers, it is widely assumed that these tissues are too prone to decay to withstand other styles of fossilization or geologically older preservation. However, Cambrian Burgess Shale-type compressions have emerged as sources of fossilized brains and nerve cords. CNS in these Cambrian fossils are preserved as carbon films or as iron oxides/hydroxides after pyrite in association with carbon. Experiments with carcasses compacted in fine-grained sediment depict preservation of neural tissue for a more prolonged temporal window than anticipated by decay experiments in other media. CNS and compound eye characters in exceptionally preserved Cambrian fossils predict divergences of the mandibulate and chelicerate ground patterns by Cambrian Stage 3 (ca 518 Ma), a dating that is compatible with molecular estimates for these splits.