Cambrian Nervous Systems for Reconstructing the Arthropod Tree of Life

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.

This project will use the earliest nervous systems from Cambrian fossils to address fundamental questions about the origin and early evolution of animal life. Its unique outcomes will appeal directly or indirectly to a diverse range of individuals/organisations.

1) Academics: the multidisciplinary nature of the research ensures its relevance to a wide range of scientists, including palaeontologists, neurobiologists, taphonomists, phylogeneticists and evolutionary biologists. Results will be published in high-impact peer-reviewed international journals. The applicant will present the results at national and international conferences. Data generated will be archived in a NERC Data Centre and/or open access websites.

2) Public sector: The Natural History Museum (NHM) in London is a world-leading research institution and a major public engagement centre that attracts 5 million visitors per year. Results from this project will contribute to enhancing the museum's research profile, increase its influence and standing overseas, and encourage more visits. The applicant will facilitate NHM and other UK colleagues establishing further international collaboration, particularly with China.

3) Educators & Students. Results will impact teachers whose purpose is to teach biological and evolutionary knowledge and concepts. The research will assist educators in providing interesting examples of key biological innovations. Consequently, the knowledge held by students of all ages will be enriched, as will their interest and understanding of evolution. The applicant will take up appropriate teaching activities and supervise research students. The NHM attracts 150,000 school visitors each year, with many targeted outreach activities and programmes to provide a forum for Museum scientists to engage with students as well as education professionals, such as "Biology AS and A-level Day".

4) General Public. This research will be attractive and accessible to most laypersons interested in nature. The project will also act as a compelling springboard for communicating to the public the fascination of how life evolved and showing how scientists understand evolution as a process. NHM scientists have a unique opportunity to publicize their results to a wide audience. The applicant will take part in Museum scientific engagement activities, such as Nature Live, and the annual event "Science Uncovered", which attracts 12,000 visitors in one night. To reach a broader public audience, the applicant will work with the NHM Press Office to promote major discoveries from the research.

5) Policy makers. High-impact research on the Chengjiang Lagerstätte will influence international understanding and collaboration between the UK and China. In 2012 UNESCO declared the Chengjiang fossil locality as a World Heritage Site, providing new opportunities to local communities, but also causing conflicts with local phosphate miners. This research will win more conservation support, bring more funding, and attract tourists to the site as a new way to generate economic growth. This international collaboration will bring together Western and Chinese experts who can contribute their knowledge and experience to local policymaking and International collaboration. In 2013, the applicant and her UK and US collaborators held a strategic meeting with the Yuxi Government to discuss how to protect the Chengjiang fossil site and how to use its World Natural Heritage status to benefit local people and the regional economy.

6) Commercial sector. Given that the extensive media and popular science coverage of palaeontology is almost invariably reported in an evolutionary context, various commercial media, such as TV, Internet, newspapers, magazines and books, will profit from this research as will the recipient public.