Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Chelicerate neural ground pattern in a Cambrian great appendage arthropod



Preservation of neural tissue in early Cambrian arthropods has recently been demonstrated1, to a degree that segmental structures of the head can be associated with individual brain neuromeres. This association provides novel data for addressing long-standing controversies about the segmental identities of specialized head appendages in fossil taxa2,3. Here we document neuroanatomy in the head and trunk of a ‘great appendage’ arthropod, Alalcomenaeus sp., from the Chengjiang biota, southwest China, providing the most complete neuroanatomical profile known from a Cambrian animal. Micro-computed tomography reveals a configuration of one optic neuropil separate from a protocerebrum contiguous with four head ganglia, succeeded by eight contiguous ganglia in an eleven-segment trunk. Arrangements of optic neuropils, the brain and ganglia correspond most closely to the nervous system of Chelicerata of all extant arthropods, supporting the assignment of ‘great appendage’ arthropods to the chelicerate total group4,5. The position of the deutocerebral neuromere aligns with the insertion of the great appendage, indicating its deutocerebral innervation and corroborating a homology between the ‘great appendage’ and chelicera indicated by morphological similarities4,6,7. Alalcomenaeus and Fuxianhuia protensa1 demonstrate that the two main configurations of the brain observed in modern arthropods, those of Chelicerata and Mandibulata, respectively8, had evolved by the early Cambrian.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: Alalcomenaeus sp. from the Chengjiang Lagerstätte.
Figure 2: Details of eye pairs and visual neuropils in Alalcomenaeus sp. YKLP 11075.
Figure 3: Leanchoiliid megacheiran arthropods from the Chengjiang Lagerstätte.
Figure 4: Nervous systems of Chelicerata.

Similar content being viewed by others


  1. Ma, X., Hou, X., Edgecombe, G. D. & Strausfeld, N. J. Complex brain and optic lobes in an early Cambrian arthropod. Nature 490, 258–261 (2012)

    Article  ADS  CAS  Google Scholar 

  2. Budd, G. E. A palaeontological solution to the arthropod head problem. Nature 417, 271–275 (2002)

    Article  ADS  CAS  Google Scholar 

  3. Yang, J., Ortega-Hernández, J., Butterfield, N. J. & Zhang, X. Specialized appendages in fuxianhuiids and the head organization of early arthropods. Nature 494, 468–471 (2013)

    Article  ADS  CAS  Google Scholar 

  4. Cotton, T. J. & Braddy, S. J. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Trans. R. Soc. Edinb. Earth Sci. 94, 169–193 (2003)

    Article  Google Scholar 

  5. Stein, M., Budd, G. E., Peel, J. S. & Harper, D. A. T. Arthroaspis n. gen., a common element of the Sirius Passet Lagerstätte (Cambrian, North Greenland), sheds light on trilobite ancestry. BMC Evol. Biol. 13, 99 (2013)

    Article  Google Scholar 

  6. Chen, J., Waloszek, D. & Maas, A. A new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia 37, 3–20 (2004)

    Google Scholar 

  7. Haug, J. T., Waloszek, D., Maas, A., Liu, Y. & Haug, C. Functional morphology, ontogeny and evolution of mantis shrimp-like predators in the Cambrian. Palaeontology 55, 369–399 (2012)

    Article  Google Scholar 

  8. Strausfeld, N. J. Arthropod Brains: Evolution, Functional Elegance, and Historical Significance (Harvard Univ. Press, 2012)

    Google Scholar 

  9. Hou, X. & Bergström, J. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata 45, 1–116 (1997)

    Google Scholar 

  10. Legg, D. A., Sutton, M. D., Edgecombe, G. D. & Caron, J.-B. Cambrian bivalved arthropod reveals origins of arthrodisation. Proc. R. Soc. Lond. B 279, 4699–4704 (2012)

    Article  Google Scholar 

  11. Edgecombe, G. D., García-Bellido, D. C. & Paterson, J. R. A new leanchoiliid megacheiran arthropod from the lower Cambrian Emu Bay Shale, South Australia. Acta Palaeontol. Pol. 56, 385–400 (2011)

    Article  Google Scholar 

  12. Haug, J. T., Briggs, D. E. G. & Haug, C. Morphology and function in the Cambrian Burgess Shale megacheiran arthropod Leanchoilia superlata and the application of a descriptive matrix. BMC Evol. Biol. 12, 162 (2012)

    Article  Google Scholar 

  13. Hou, X.-G. et al. The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life (Blackwell, 2004)

  14. Liu, Y., Hou, X. & Bergström, J. Chengjiang arthropod Leanchoilia illecebrosa (Hou, 1987) reconsidered. GFF 129, 263–272 (2007)

    Article  Google Scholar 

  15. Briggs, D. E. G. & Collins, D. The arthropod Alalcomenaeus cambricus Simonetta, from the Middle Cambrian Burgess Shale of British Columbia. Palaeontology 42, 953–977 (1999)

    Article  Google Scholar 

  16. Brenneis, G. & Richter, S. Architecture of the nervous system in Mystacocarida (Arthropoda, Crustacea)—an immunohistochemical study and 3D reconstruction. J. Morphol. 271, 169–189 (2010)

    PubMed  Google Scholar 

  17. Damen, W. G., Hausdorf, M., Seyfarth, E. A. & Tautz, D. A conserved mode of head segmentation in arthropods revealed by the expression pattern of Hox genes in a spider. Proc. Natl Acad. Sci. USA 95, 10665–10670 (1998)

    Article  ADS  CAS  Google Scholar 

  18. García-Bellido, D. C. & Collins, D. Reassessment of the genus Leanchoilia (Arthropoda, Arachnomorpha) from the Middle Cambrian Burgess Shale, British Columbia, Canada. Palaeontology 50, 693–709 (2007)

    Article  Google Scholar 

  19. Richter, S., Stein, M., Frase, T. & Szucsich, N. U. in Arthropod Biology and Evolution (eds Minelli A., Boxshall G. & Fusco G. ) The Arthropod Head 223–240 (Springer, 2013)

    Google Scholar 

  20. Butterfield, N. J. Leanchoilia guts and the interpretation of three-dimensional structures in Burgess Shale-type fossils. Paleobiology 28, 155–171 (2002)

    Article  Google Scholar 

  21. Lehmann, T., Hess, M. & Melzer, R. R. Wiring a periscope - ocelli, retinula axons, visual neuropils and the ancestrality of sea spiders. PLoS ONE 7, e30474 (2012)

    Article  ADS  CAS  Google Scholar 

  22. Harzsch, S. et al. Evolution of arthropod visual systems: development of the eyes and central visual pathways in the horseshoe crab Limulus polyphemus Linnaeus, 1758 (Chelicerata, Xiphosura). Dev. Dyn. 235, 2641–2655 (2006)

    Article  CAS  Google Scholar 

  23. Strausfeld, N. J., Weltzien, P. & Barth, F. G. Two visual systems in one brain: neuropil serving the principal eyes of the spider Cupiennius salei. J. Comp. Neurol. 328, 63–75 (1993)

    Article  CAS  Google Scholar 

  24. Strausfeld, N. J. & Andrew, D. R. A new view of insect-crustacean relationships. I. Inferences from neural cladistics and comparative neuroanatomy. Arthropod Struct. Dev. 40, 276–288 (2011)

    Article  Google Scholar 

  25. Zeil, J. Sexual dimorphism in the visual system of flies: the divided brain of male Bibionidae (Diptera). Cell Tissue Res. 229, 591–610 (1983)

    Article  CAS  Google Scholar 

  26. Lin, C. & Strausfeld, N. J. A precocious adult visual center in the larva defines the unique optic lobe of the split-eyed whirligig beetle Dineutus sublineatus. Front. Zool. 10, 7 (2013)

    Article  Google Scholar 

  27. Schoenemann, B. & Clarkson, E. N. K. The eyes of Leanchoilia. Lethaia 45, 524–531 (2012)

    Article  Google Scholar 

  28. Eriksson, M. E. & Terfelt, F. Exceptionally preserved Cambrian trilobite digestive system revealed in 3D by synchrotron-radiation X-ray tomographic microscopy. PLoS ONE 7, e35625 (2012)

    Article  ADS  CAS  Google Scholar 

  29. Eriksson, M. E., Terfelt, F., Elofsson, R. & Marone, F. Internal soft-tissue anatomy of Cambrian ‘Orsten’ arthropods as revealed by synchrotron X-ray tomographic microscopy. PLoS ONE 7, e42582 (2012)

    Article  ADS  CAS  Google Scholar 

Download references


We thank N. Shimobayashi, H. Maeda, and T. Kogiso for arranging and performing EDXRF analyses, and D. Andrew for advice on cladistics. This work was supported by grants from the Natural Science Foundation of China (no. 40730211), Research in Education and Science from the Government of Japan (no. 21740370), a Leverhulme Trust Research Project Grant (F/00 696/T), by the Center for Insect Science, University of Arizona, and a grant from the Air Force Research Laboratories (FA8651-10-1-0001) to N.J.S.

Author information

Authors and Affiliations



The project was conceived by G.T. Fossil data were analysed by all authors. G.D.E., N.J.S. and X.M. composed the text.

Corresponding authors

Correspondence to Xianguang Hou or Nicholas J. Strausfeld.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Cephalic region of Alalcomenaeus sp. YKLP 11075

All in dorsal view, composites of part and counterpart (upper left). Second left to right: CT scan (green); EDXRF Fe (red); superimposition of CT and EDXRF Fe. Lower row, left to right: EDXRF Cu (blue); superimposition of CT and EDXRF Cu; superimposition of EDXRF Fe and EDXRF Cu; superimposition of all scans. C1, first post-GA neuropil = tritocerebrum (tri); C2, second post-GA neuropil; GA, great appendage neuropil = deutocerebrum (deu); on1, first optic neuropil; pr, protocerebrum.

Extended Data Figure 2 Arthropod relationships based on neuroanatomical characters.

Strict consensus of 34 shortest cladograms based on 145 characters in Supplementary Information Table 2.

Supplementary information

Supplementary Information

This file contains Supplementary Tables 1-2, Phylogenetic Methods and Supplementary References. (PDF 249 kb)

Supplementary Data

This zipped file contains characters coded in phylogenetic analysis (in nexus format, it can be opened in freeware such as Mesquite and Nexus Data Editor). (ZIP 3 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Tanaka, G., Hou, X., Ma, X. et al. Chelicerate neural ground pattern in a Cambrian great appendage arthropod. Nature 502, 364–367 (2013).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing