Skip to main content

Thank you for visiting nature.com. 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.

  • Letter
  • Published:

A Silurian sea spider

Abstract

Pycnogonids (sea spiders) are marine arthropods numbering some 1,160 extant species. They are globally distributed in depths of up to 6,000 metres, and locally abundant1,2; however, their typically delicate form and non-biomineralized cuticle has resulted in an extremely sparse fossil record that is not accepted universally3. There are two opposing views of their phylogenetic position: either within Chelicerata as sister group to the euchelicerates4,5,6,7, or as a sister taxon to all other euarthropods8. The Silurian Herefordshire Konservat-Lagerstätte9 in England ( 425 million years (Myr) bp) yields exceptionally preserved three-dimensional fossils that provide unrivalled insights into the palaeobiology of a variety of invertebrates10,11,12,13,14. The fossils are preserved as calcitic void in-fills in carbonate concretions within a volcaniclastic horizon15, and are reconstructed digitally12. Here we describe a new pycnogonid from this deposit, which is the oldest adult sea spider by 35 Myr and the most completely known fossil species. The large chelate first appendage is consistent with a chelicerate affinity for the pycnogonids. Cladistic analyses place the new species near the base of the pycnogonid crown group, implying that the latter had arisen by the Silurian period.

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

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

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

Figure 1: Haliestes dasos and the extant pycnogonid Nymphon gracile.
Figure 2: Strict consensus (consistency index = 0.38, retention index = 0.66) of three most-parsimonious trees of length 203 obtained from analysis of data matrix (see Supplementary Table).

Similar content being viewed by others

References

  1. King, P. E. Pycnogonids (Hutchinson, London, 1973)

    Google Scholar 

  2. Arnaud, F. & Bamber, R. N. The biology of Pycnogonida. Adv. Mar. Biol. 24, 1–96 (1987)

    Google Scholar 

  3. Child, C. A. The marine fauna of New Zealand: Pycnogonida (sea spiders). Natl Inst. Water Atmos. Res. Biodiv. Memoir 109, 1–71 (1998)

    Google Scholar 

  4. Waloszek, D. & Dunlop, J. A. A larval sea spider (Arthropoda: Pycnogonida) from the Upper Cambrian ‘Orsten’ of Sweden, and the phylogenetic position of pycnogonids. Palaeontology 45, 421–446 (2002)

    Article  Google Scholar 

  5. Vilpoux, K. & Waloszek, D. Larval development and morphogenesis of the sea spider Pycnogonum litorale (Ström, 1762) and the tagmosis of the body of Pantopoda. Arthrop. Struct. Dev. 32, 349–383 (2003)

    Article  Google Scholar 

  6. Boxshall, G. A. The evolution of arthropod limbs. Biol. Rev. 79, 253–300 (2004)

    Article  Google Scholar 

  7. Dunlop, J. A. & Arango, C. P. Pycnogonid affinities: a review. J. Zool. Syst. Evol. Res. (in the press)

  8. Giribet, G., Edgecombe, G. D. & Wheeler, W. C. Arthropod phylogeny based on eight molecular loci and morphology. Nature 413, 157–161 (2001)

    Article  ADS  CAS  Google Scholar 

  9. Briggs, D. E. G., Siveter, David J. & Siveter, Derek J. Soft-bodied fossils from a Silurian volcaniclastic deposit. Nature 382, 248–250 (1996)

    Article  ADS  CAS  Google Scholar 

  10. Sutton, M. D., Briggs, D. E. G., Siveter, David J. & Siveter, Derek J. An exceptionally preserved vermiform mollusc from the Silurian of England. Nature 410, 461–463 (2001)

    Article  ADS  CAS  Google Scholar 

  11. Sutton, M. D., Briggs, D. E. G., Siveter, David J. & Siveter, Derek J. A three-dimensionally preserved fossil polychaete worm from the Silurian of Herefordshire, England. Proc. R. Soc. Lond. B 268, 2355–2363 (2001)

    Article  CAS  Google Scholar 

  12. Sutton, M. D., Briggs, D. E. G., Siveter, David J., Siveter, Derek J. & Orr, P. J. The arthropod Offacolus kingi (Chelicerata) from the Silurian of Herefordshire, England: computer based morphological reconstructions and phylogenetic affinities. Proc. R. Soc. Lond. B 269, 1195–1203 (2002)

    Article  Google Scholar 

  13. Siveter, David J., Sutton, M. D., Briggs, D. E. G. & Siveter, Derek J. An ostracode crustacean with soft parts from the Lower Silurian. Science 302, 1749–1751 (2003)

    Article  ADS  CAS  Google Scholar 

  14. Briggs, D. E. G., Sutton, M. D., Siveter, David J. & Siveter, Derek J. A new phyllocarid (Crustacea: Malacostraca) from the Silurian Fossil-Lagerstätte of Herefordshire, UK. Proc. R. Soc. Lond. B 271, 131–138 (2004)

    Article  Google Scholar 

  15. Orr, P. J., Briggs, D. E. G., Siveter, David J. & Siveter, Derek J. Three-dimensional preservation of a non-biomineralized arthropod in concretions in Silurian volcaniclastic rocks from Herefordshire, England. J. Geol. Soc. Lond. 157, 173–186 (2000)

    Article  CAS  Google Scholar 

  16. Miyazaki, K. J. On the shape of the foregut lumen in sea spiders (Arthropoda: Pycnogonida). Mar. Biol. Ass. UK 82, 1037–1038 (2002)

    Article  Google Scholar 

  17. Bergström, J., Stürmer, W. & Winter, G. Palaeoisopus, Palaeopantopus and Palaeothea, pycnogonid arthropods from the Lower Devonian Hunsrück Slate, West Germany. Paläont. Zeit. 54, 7–54 (1980)

    Article  Google Scholar 

  18. Bartels, C., Briggs, D. E. G. & Brassel, G. The Fossils of the Hunsrück Slate (Cambridge Univ. Press, 1998)

    Google Scholar 

  19. Wilby, P. R., Briggs, D. E. G. & Riou, B. Mineralization of soft-bodied invertebrates in a Jurassic metalliferous deposit. Geology 24, 847–850 (1996)

    Article  ADS  CAS  Google Scholar 

  20. Arango, C. P. Morphological phylogenetics of the sea spiders (Arthropoda: Pycnogonida). Org. Divers. Evol. 2, 107–125 (2002)

    Article  Google Scholar 

  21. Arango, C. P. Molecular approach to the phylogenetics of sea spiders (Arthropoda: Pycnogonida) using partial sequences of nuclear ribosomal DNA. Mol. Phylogenet. Evol. 28, 588–600 (2003)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Leverhulme Trust, NERC and English Nature. K. Saunders is thanked for technical assistance; C. Arango, R. Bamber and D. Waloszek for discussion; G. Boxshall, J. Dunlop and D. Waloszek for pre-prints of their papers; S. de Grave for providing Recent material; and R. Fenn, T. Hall and J. Sinclair for general assistance.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Derek J. Siveter.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Figure 1

Expansion of Figure 2; cladogram of pycnogonids including fossil taxa (see Figure 2 for legend). (JPG 117 kb)

Supplementary Methods

Details of methodology for cladistic analyses. (DOC 20 kb)

Supplementary Note 1

Details of functional argument for interpretation of walking-leg segmentation. (DOC 21 kb)

Supplementary Note 2

Details of general functional morphology and mode of life. (DOC 29 kb)

Supplementary Table 1

Data matrix and character definitions for cladistic analyses. (XLS 49 kb)

Supplementary Video 1

Movie comprising serial grinding images from OUM C.29571. Slice interval is 20 µm, field of view horizontally is 5.15 mm. (MP4 912 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Siveter, D., Sutton, M., Briggs, D. et al. A Silurian sea spider. Nature 431, 978–980 (2004). https://doi.org/10.1038/nature02928

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature02928

This article is cited by

Comments

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.

Search

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