Cambrian Nervous Systems for Reconstructing the Arthropod Tree of Life

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项目编号	NE/L011751/2
	Cambrian Nervous Systems for Reconstructing the Arthropod Tree of Life
	Xiaoya Ma
主持机构	University of Exeter
项目开始年	2018
	2018-06-01
项目结束日期	2020-04-30
资助机构	UK-NERC
项目类别	Fellowship
项目经费	207977(GBP)
国家	英国
语种	英语
英文摘要	Arthropods are invertebrate animals with an exoskeleton, a segmented body, and jointed legs, such as insects, crabs, spiders and centipedes. Arthropoda is by far the largest and most diverse phylum today and is closely related to two smaller phyla, Onychophora (velvet worms) and Tardigrada (water bears), together forming Panarthropoda. They first appear 520 million years ago (Mya) in the "Cambrian Explosion", marked by the sudden appearance of most major animal phyla in the fossil record. The long geological history and exceptional diversity of panarthropods make them ideal candidates for understanding the origin and early evolution of animals, and it is thus fundamental to investigate their Cambrian fossil record. The great diversity in the external appearance of panarthropods makes it difficult to understand their interrelationships. In contrast, recent studies show that the evolution of the central nervous system (CNS) has been remarkably conservative, and while variations between species can be recognised, the general arrangement within each major group has been very stable. Therefore, the CNS provides a primary source of data for understanding the relationships of major panarthropod groups. Unfortunately, extant species cannot inform us about the earliest panarthropod brains and nervous systems, or their early evolutionary history. Only fossils, which record the earliest stages in the evolution of arthropods, can provide the answers. Soft parts of animals tend to decay away quickly after death, so most arthropod fossils are the remains of hard parts (e.g. exoskeletons) and much less is known about their internal anatomy. However, under exceptional circumstances, the unmineralised soft tissue of organisms can also be preserved in exquisite detail, such as in two famous Cambrian fossil assemblages: the Chengjiang biota, southwest China (circa 520 Mya), and the Burgess Shale, Canada (circa 505 Mya). Both yield abundant panarthropod fossils with exceptionally preserved external morphology and internal anatomy, providing crucial information about the earliest panarthropods. Countering orthodox assumptions that neural tissue does not withstand fossilization, the applicant and her colleagues recently reported exceptionally preserved brains and nervous systems from Chengjiang arthropods, which added a fresh injection of data for understanding fossil arthropods and established a new research field, "neuropalaeontology". Further provisional studies have discovered the brain and other neural tissues in even earlier-derived fossil panarthropods, providing vital information regarding the origin of arthropod brains; as well as new discoveries of exceptionally preserved circulatory systems (previously all but unknown in the arthropod fossil record) and sensory structures (e.g. eyes and sense organs on the antennae) from Cambrian panarthropods. Together with their CNS, these provide unique insights into the ecology and evolution of early panarthropods. The aim of this project is to accurately document the CNS, sensory structures and other internal organ systems from exceptionally preserved Cambrian panarthropods (e.g. lobopodians, anomalocaridids and arthropods) of the Chengjiang and Burgess Shale biotas and compare the data with living groups, so as to increase our understanding of the evolutionary relationships between major groups during the early stages of radiation and divergence.
来源学科分类	Natural Environment Research
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/87124
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Xiaoya Ma.Cambrian Nervous Systems for Reconstructing the Arthropod Tree of Life.2018.