A primitive fish from the Cambrian of North America

Published online:


Knowledge of the early evolution of fish largely depends on soft-bodied material from the Lower (Series 2) Cambrian period of South China1,2. Owing to the rarity of some of these forms and a general lack of comparative material from other deposits, interpretations of various features remain controversial3,4, as do their wider relationships amongst post-Cambrian early un-skeletonized jawless vertebrates. Here we redescribe Metaspriggina5 on the basis of new material from the Burgess Shale and exceptionally preserved material collected near Marble Canyon, British Columbia6, and three other Cambrian Burgess Shale-type deposits from Laurentia. This primitive fish displays unambiguous vertebrate features: a notochord, a pair of prominent camera-type eyes, paired nasal sacs, possible cranium and arcualia, W-shaped myomeres, and a post-anal tail. A striking feature is the branchial area with an array of bipartite bars. Apart from the anterior-most bar, which appears to be slightly thicker, each is associated with externally located gills, possibly housed in pouches. Phylogenetic analysis places Metaspriggina as a basal vertebrate, apparently close to the Chengjiang taxa Haikouichthys1,2,3,4 and Myllokunmingia1, demonstrating also that this primitive group of fish was cosmopolitan during Lower–Middle Cambrian times (Series 2–3). However, the arrangement of the branchial region in Metaspriggina has wider implications for reconstructing the morphology of the primitive vertebrate. Each bipartite bar is identified as being respectively equivalent to an epibranchial and ceratobranchial. This configuration suggests that a bipartite arrangement is primitive and reinforces the view that the branchial basket of lampreys7 is probably derived. Other features of Metaspriggina, including the external position of the gills and possible absence of a gill opposite the more robust anterior-most bar, are characteristic of gnathostomes8 and so may be primitive within vertebrates.

  • Subscribe to Nature for full access:



Additional access options:

Already a subscriber?  Log in  now or  Register  for online access.


  1. 1.

    et al. Lower Cambrian vertebrates from South China. Nature 402, 42–46 (1999)

  2. 2.

    et al. Head and backbone of the Early Cambrian vertebrate Haikouichthys. Nature 421, 526–529 (2003)

  3. 3.

    , , , & New evidence on the anatomy and phylogeny of the earliest vertebrates. Proc. R. Soc. Lond. B 269, 1865–1869 (2002)

  4. 4.

    & Evidence for a single median fin-fold and tail in the Lower Cambrian vertebrate, Haikouichthys ercaicunensis. J. Evol. Biol. 17, 1162–1166 (2004)

  5. 5.

    A redescription of a rare chordate, Metaspriggina walcotti Simonetta and Insom, from the Burgess Shale (Middle Cambrian), British Columbia, Canada. J. Paleontol. 82, 424–430 (2008)

  6. 6.

    et al. A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies. Nature Commun. 5, 3210 (2014)

  7. 7.

    , & Development of the viscerocranial skeleton during embryogenesis of the sea lamprey, Petromyzon marinus. Dev. Dyn. 238, 3126–3138 (2009)

  8. 8.

    Early Vertebrates (Oxford Monographs on Geology and Geophysics) Vol. 33 (Clarendon, 1996)

  9. 9.

    & Pikaia gracilens Walcott, a stem-group chordate from the Middle Cambrian of British Columbia. Biol. Rev. Camb. Philos. Soc. 87, 480–512 (2012)

  10. 10.

    & Pikaia gracilens Walcott: stem chordate, or already specialized in the Cambrian? J. Exp. Zool. B Mol. Dev. Evol. 320, 247–271 (2013)

  11. 11.

    , & Atlas of vertebrate decay: a visual and taphonomic guide to fossil interpretation. Palaeontology 56, 457–474 (2013)

  12. 12.

    , & A new Middle Cambrian, Burgess Shale-type biota, Bolaspidella Zone, Chancellor Basin, southeastern British Columbia. Palaeogeogr. Palaeoclimatol. Palaeoecol. 277, 106–126 (2009)

  13. 13.

    Systematic revision of the Cambrian trilobite Bathynotus Hall, 1860, with documentation of new occurrences in western Laurentia and implications for intercontinental biostratigraphic correlation. Mem. Assoc. Australasian Palaeontologists 37, 369–406 (2009)

  14. 14.

    Ediacaran-like fossils in Cambrian Burgess Shale-type faunas of North America. Palaeontology 36, 593–635 (1993)

  15. 15.

    The Middle Cambrian fossil Pikaia and the evolution of chordate swimming. EvoDevo 3, 12 (2012)

  16. 16.

    A mechanical analysis of myomere shape in fish. J. Exp. Biol. 202, 3405–3414 (1999)

  17. 17.

    , & Developmental evidence for serial homology of the vertebrate jaw and gill arch skeleton. Nature Commun. 4, 1436 (2013)

  18. 18.

    Evolution of the vertebrate jaw from developmental perspectives. Evol. Dev. 14, 76–92 (2012)

  19. 19.

    Developmental studies of the lamprey and hierarchical evolutionary steps towards the acquisition of the jaw. J. Anat. 207, 489–499 (2005)

  20. 20.

    , , , & Fossil jawless fish from China foreshadows early jawed vertebrate anatomy. Nature 476, 324–327 (2011)

  21. 21.

    & The anatomy of Euphanerops longaevus Woodward, 1900, an anaspid-like jawless vertebrate from the Upper Devonian of Miguasha, Quebec, Canada. Geodiversitas 29, 143–216 (2007)

  22. 22.

    , , & Lamprey-like gills in a gnathostome-related Devonian jawless vertebrate. Nature 440, 1183–1185 (2006)

  23. 23.

    , & A lamprey from the Devonian period of South Africa. Nature 443, 981–984 (2006)

  24. 24.

    Early vertebrate evolution: pharyngeal structure and the origin of gnathostomes. J. Zool. 204, 169–183 (1984)

  25. 25.

    & Tweaking the hinge and caps: testing a model of the organization of jaws. J. Exp. Zool. B Mol. Dev. Evol. 310, 315–335 (2008)

  26. 26.

    & New perspectives on pharyngeal dorsoventral patterning in development and evolution of the vertebrate jaw. Dev. Biol. 371, 121–135 (2012)

  27. 27.

    , , & barx1 represses joints and promotes cartilage in the craniofacial skeleton. Development 140, 2765–2775 (2013)

Download references


We thank T. Lacalli for comments on an earlier draft of the manuscript, J. Mallatt for an extensive series of critiques, and J. Hoyal-Cuthill and C. Aria for assistance with phylogenetic analyses. We also thank M. Collins for technical drawings and reconstructions, and R. Thomas and M. Webster for information on the Kinzers and Parker formations, respectively. S.C.M. thanks V. Brown for manuscript preparation, and the Department of Earth Sciences and St John’s College, Cambridge for support. We thank Parks Canada for granting a collection and research permit to J.-B.C. (YNP-2012-12054). Fieldwork support for the 2012 expedition comes from the Royal Ontario Museum (DMV Research and Acquisition Fund and DNH Fieldwork Fund), M. Streng (Uppsala University and the Swedish Research Council), R. Gaines (Pomona College), G. Mangáno (University of Saskatchewan) and a Natural Sciences and Engineering Research Council Discovery Grant (to J.-B.C., #341944). This is Royal Ontario Museum Burgess Shale project number 53.

Author information


  1. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK

    • Simon Conway Morris
  2. Department of Natural History (Palaeobiology), Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada

    • Jean-Bernard Caron
  3. University of Toronto, Department of Ecology and Evolutionary Biology, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada

    • Jean-Bernard Caron


  1. Search for Simon Conway Morris in:

  2. Search for Jean-Bernard Caron in:


J.-B.C. collected fossils, prepared all illustrative material and conducted phylogenetic analyses. S.C.M. wrote early drafts of paper, and both authors discussed results and developed observations and conclusions.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Simon Conway Morris or Jean-Bernard Caron.

Extended data

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    This file contains Supplementary Text and Data.


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.