Skip to main content Accessibility help

New phylogenetic insights into the Cambrian radiation of arachnomorph arthropods

  • Jonathan R. Hendricks (a1) and Bruce S. Lieberman (a1) (a2)


The Cambrian fossil record of the Arachnomorpha is rich and diverse and includes trilobites, chelicerates, and many taxa known from various soft-bodied faunas including the Burgess Shale and the Chengjiang. Exceptionally well-preserved arthropod fossils are also known from Middle Cambrian strata in Utah. Recently, two new arachnomorphs (Dicranocaris Briggs, Lieberman, Hendricks, Halgedahl, and Jarrard, 2008 and Nettapezoura Briggs, Lieberman, Hendricks, Halgedahl, and Jarrard, 2008) were described from the Wheeler and Marjum formations of Utah. Cladistic analysis is undertaken to investigate arachnomorph relationships in light of these two new genera. The character matrix of Edgecombe and Ramsköld (1999) serves as the foundation for this study, augmented by new characters and taxa. The results of our cladistic analysis suggest that at least three distinct arachnomorph clades had diverged by the Middle Cambrian, and perhaps much earlier; the Utah genera can be referred to groups within one of these clades.



Hide All
Bergström, J. and Hou, X.-G. 2003. Arthropod origins. Bulletin of Geosciences, 78:323334.
Bremer, K. 1988. The limits of amino acid sequence data in angiosperm phylogenetic reconstruction. Evolution, 42:795803.
Bremer, K. 1994. Branch support and tree stability. Cladistics, 10:295304.
Briggs, D. E. G., Bruton, D. L., and Whittington, H. B. 1979. Appendages of the arthropod Aglaspis spinifer (Upper Cambrian, Wisconsin) and their significance. Palaeontology, 22:167180.
Briggs, D. E. G. and Collins, D. 1988. A Middle Cambrian Chelicerate from Mount Stephen, British Columbia. Palaeontology, 31:779798.
Briggs, D. E. G. and Collins, D. 1999. The arthropod Alalcomenaeus cambricus Simonetta, from the Middle Cambrian Burgess Shale of British Columbia. Palaeontology, 42:953977.
Briggs, D. E. G. and Fortey, R. A. 1989. The early radiation and relationships of the major arthropod groups. Science, 246:241243.
Briggs, D. E. G., Fortey, R. A., and Wills, M. A. 1992. Morphological disparity in the Cambrian. Science, 256:16701673.
Briggs, D. E. G., Lieberman, B. S., Hendricks, J. R., Halgedahl, S. L., and Jarrard, R. D. 2008. Soft-bodied arthropods from the Middle Cambrian of Utah. Journal of Paleontology, 82:238254.
Bruton, D. L. and Whittington, H. B. 1983. Emeraldella and Leanchoilia, two arthropods from the Burgess Shale, Middle Cambrian, British Columbia. Philosophical Transactions of the Royal Society of London. B 300: 553582.
Budd, G. E. 2002. A palaeontological solution to the arthropod head problem. Nature, 417:271275.
Chen, J.-Y., Edgecombe, G. D., and Ramsköld, L. 1997. Morphological and ecological disparity in naraoiids (Arthropoda) from the Early Cambrian Chengjiang Fauna, China. Records of the Australian Museum, 49:124.
Chen, J.-Y., Waloszek, D., and Mass, A. 2004. A new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia, 37:320.
Chen, J.-Y., Zhou, G.-Q., Zhu, M.-Y., and Yeh, K.-Y. 1996. The Chengjiang Biota. A Unique Window of the Cambrian Explosion. National Museum of Natural Science, Taichung, 222 p.
Cotton, T. J. and Braddy, S. J. 2004. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences, 94:169193.
Dunlop, J. A. 2005. New ideas about the euchelicerate stem-lineage. Acta zoologica bulgarica, Suppl. No. 1:923.
Dunlop, J. A. and Selden, P. A. 1998. The early history and phylogeny of the chelicerates, p. 221235. In Fortey, R. A. and Thomas, R. H. (eds.), Arthropod relationships. Chapman & Hall, London.
Dzik, J. and Lendzion, K. 1988. The oldest arthropods of the East European Platform. Lethaia, 21:2938.
Edgecombe, G. D. and Ramsköld, L. 1999. Relationships of Cambrian Arachnata and the systematic position of Trilobita. Journal of Paleontology, 73:263287.
Farris, J. S. 1989. The retention index and rescaled consistency index. Cladistics, 5:417419.
Fortey, R. A., Briggs, D. E. G., and Wills, M. A. 1996. The Cambrian evolutionary ‘explosion’: decoupling cladogenesis from morphological disparity. Biological Journal of the Linnaean Society, 57:1333.
Fortey, R. A., Briggs, D. E. G., and Wills, M. A. 1997. The Cambrian evolutionary ‘explosion’ recalibrated. BioEssays, 19:429434.
Fortey, R. A. and Theron, J. N. 1994. A new Ordovician arthropod, Soomapsis, and the agnostid problem. Palaeontology, 37:841861.
García-Bellido, D. C. and Collins, D. H. 2006. A new study of Marrella splendens (Arthropoda, Marrellomorpha) from the Middle Cambrian Burgess Shale, British Columbia, Canada. Canadian Journal of Earth Sciences, 43:721742.
García-Bellido, D. C. and Collins, D. H. 2007. Reassessment of the genus Leanchoilia (Arthropoda, Arachnomorpha) from the Middle Cambrian Burgess Shale, British Columbia, Canada. Palaeontology, 50:693709.
Goloboff, P. 1993. NONA, version 1.6. Published by the author, Tucumán, Argentina.
Hall, J. 1862. A new crustacean from the Potsdam Sandstone. Canadian Naturalist, 7.
Hammann, W., Laske, R., and Pillola, G. L. 1990. Tariccoia arrusensis n. g. n. sp., an unusual trilobite-like arthropod. Rediscovery of the “phyllocarid” beds of Taricco (1922) in the Ordovician “Puddinga” sequence of Sardinia. Bolletino della Società Paleontologica Italiana, 29.
Hou, X.-G. 1987. Three new large arthropods from Lower Cambrian, Chengjiang, eastern Yunnan. Acta Palaeontologica Sinica, 26:272285.
Hou, X.-G., Aldridge, R. J., Bergström, J., Siveter, D. J., Siveter, D. J., and Feng, X.-H. 2004. The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life. Blackwell Science Ltd., Malden, Massachusetts, 233 p.
Hou, X.-G. and Bergström, J. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata, 45:1116.
Hou, X.-G., Chen, J.-Y., and Lu, H.-Z. 1989. Early Cambrian new arthropods from Chengjiang, Yunnan. Acta Palaeontologica Sinica, 28:4257.
Hou, X.-G., Ramsköld, L., and Bergström, J. 1991. Composition and preservation of the Chengjiang fauna-a Lower Cambrian soft-bodied biota. Zoologica Scripta, 20:395411.
Kluge, A. G. 1989. A concern for evidence and a phylogenetic hypothesis of relationships among Epicrates (Boidae, Serpentes). Systematic Zoology, 38:725.
Kluge, A. G. and Farris, J. S. 1969. Quantitative phyletics and the evolution of anurans. Systematic Zoology, 18:132.
Lieberman, B. S. 2003. Taking the pulse of the Cambrian radiation. Integrative and Comparative Biology, 43:229237.
Meert, J. G. and Lieberman, B. S. 2004. A palaeomagnetic and palaeobiogeographic perspective on latest Neoproterozoic and early Cambrian tectonic events. Journal of the Geological Society of London, 161:111.
Moore, R. A., Briggs, D. E. G., and Bartels, C. 2005. A new specimen of Weinbergina opitzi (Chelicerata: Xiphosura) from the Lower Devonian Hunsriick Slate, Germany. Paläontologische Zeitschrift, 79:399408.
Nixon, K. C. 1999-2002. WinClada, version 1.00.08. Published by the author, Ithaca, New York.
Nixon, K. C. and Carpenter, J. M. 1996. On simultaneous analysis. Cladistics, 12:221241.
Ogg, J. G. 2004. Status of divisions of the International Geologic Time Scale. Lethaia, 37:183199.
Raymond, P. E. 1920. The appendages, anatomy and relationships of trilobites. Memoirs of the Connecticut Academy of Arts and Science, 7:1169.
Richter, R. and Richter, E. 1929. Weinbergina opitzi, n.g., n.sp., ein Schwertträger (Merost., Xiphos,) aus dem Devon (Rheinland). Senckenbergiana, 11:193209.
Rominger, C. 1887. Description of primordial fossils from Mt. Stephens, N. W. Territory of Canada. Proceedings of the Academy of Natural Sciences of Philadelphia 1887:1219.
Scholtz, G. and Edgecombe, G. D. 2005. Heads, hox and the phylogenetic position of trilobites, p. 139165. In Koenemann, S. and Jenner, R. (eds.), Crustacea and Arthropod Relationships (Crustacean Issues 16). CRC, Boca Raton, Florida.
Scholtz, G. and Edgecombe, G. D. 2006. The evolution of arthropod heads: reconciling morphological, developmental and palaeontological evidence. Development Genes and Evolution, 216:395415.
Simmonetta, A. 1970. Studies on non trilobite arthropods of the Burgess Shale (Middle Cambrian). Palaeontographica Italica, 56:3545.
Simonetta, A. M. and Delle Cave, L. 1975. The Cambrian non trilobite arthropods from the Brugess Shale of British Columbia. A study of their comparative morphology, taxonomy, and evolutionary significance. Palaeontographica Italica, 69.
Størmer, L. 1944. On the relationships and phylogeny of fossil and recent Arachnomorpha: a comparative study on Arachnida, Xiphosura, Eurypterida, Trilobita, and other fossil Arthropoda. Skrifter Utgitt av det Norske Videnskaps-Academi i Oslo, I. Matematisk-Naturvidenskapelig. Klasse, 5: 1158.
Swofford, D. L. and Olsen, G. J. 1990. Phylogeny reconstruction, p. 411501. In Hillis, D. M. and Moritz, C. (eds.), Molecular Systematics. Sinauer Associates, Inc., Sunderland, Massachusetts.
Van Roy, P. 2006. An aglaspidid arthropod from the Upper Ordovician of Morocco with remarks on the affinities and limitations of Aglaspidida. Transactions of the Royal Society of Edinburgh (Earth Sciences), 96:327350.
Walcott, C. D. 1911. Middle Cambrian Merostomata. Cambrian Geology and Paleontology II. Smithsonian Miscellaneous Collections, 57:1740.
Walcott, C. D. 1912. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Cambrian Geology and Paleontology II. Smithsonian Miscellaneous Collections, 57:145228.
Walcott, C. D. 1918. Geological explorations in the Canadian Rockies. Explorations and fieldwork of the Smithsonian Institution in 1917. Smithsonian Miscellaneous Collections, 68:420.
Wills, M. A., Briggs, D. E. G., Fortey, R. A., Wilkinson, M., and Sneath, P. H. A. 1998. An arthropod phylogeny based on fossil and recent taxa, p. 33105. In Edgecombe, G. D. (ed.), Arthropod Fossils and Phylogeny. Columbia University Press, New York.
Zhang, W.-T. 1951. Trilobites from the Shipai Shale and their stratigraphical significance, 2, 10 p.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Paleontology
  • ISSN: 0022-3360
  • EISSN: 1937-2337
  • URL: /core/journals/journal-of-paleontology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed