Letter | Published:

Hyoliths are Palaeozoic lophophorates

Nature volume 541, pages 394397 (19 January 2017) | Download Citation


Hyoliths are abundant and globally distributed ‘shelly’ fossils that appear early in the Cambrian period and can be found throughout the 280 million year span of Palaeozoic strata1,2. The ecological and evolutionary importance of this group has remained unresolved, largely because of their poorly constrained soft anatomy and idiosyncratic scleritome, which comprises an operculum, a conical shell and, in some taxa, a pair of lateral spines (helens)3,4,5. Since their first description over 175 years ago, hyoliths have most often been regarded as incertae sedis4,6, related to molluscs7,8 or assigned to their own phylum1,2. Here we examine over 1,500 specimens of the mid-Cambrian hyolith Haplophrentis from the Burgess Shale and Spence Shale Lagerstätten. We reconstruct Haplophrentis as a semi-sessile, epibenthic suspension feeder that could use its helens to elevate its tubular body above the sea floor3,9,10,11,12. Exceptionally preserved soft tissues include an extendable, gullwing-shaped, tentacle-bearing organ surrounding a central mouth, which we interpret as a lophophore, and a U-shaped digestive tract ending in a dorsolateral anus. Together with opposing bilateral sclerites and a deep ventral visceral cavity, these features indicate an affinity with the lophophorates (brachiopods, phoronids and tommotiids), substantially increasing the morphological disparity of this prominent group.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    Skeletal microstructures of hyoliths from the early Cambrian of Siberia. Alcheringa 24, 65–81 (2000)

  2. 2.

    et al. Biology of the Hyolitha. Lethaia 8, 181–191 (1975)

  3. 3.

    A hyolithid with preserved soft parts from the Ordovician Fezouata Konservat-Lagerstätte of Morocco. Palaeogeogr. Palaeoclimatol. Palaeoecol. 460, 122–129 (2016)

  4. 4.

    , , , & Terreneuvian orthothecid (Hyolitha) digestive tracts from northern Montagne Noire, France; taphonomic, ontogenetic and phylogenetic implications. PLoS One 9, e88583 (2014)

  5. 5.

    & Taxonomy and paleobiology of some Middle Cambrian Scenella (Cnidaria) and hyolithids (Mollusca) from western North America. University of Kansas Paleontological Contributions (paper 121) (1988)

  6. 6.

    , , & Early Cambrian fossils from South Australia. Memoirs of the Association of Australasian Palaeontologists 9, 345–364 (1990)

  7. 7.

    & On the systematic position of the Hyolitha (Kingdom Animalia). Memoirs of the Association of Australasian Palaeontologists 34, 521–536 (2007)

  8. 8.

    & Aspects of the biology of Hyolitha (Mollusca). Lethaia 9, 65–82 (1976)

  9. 9.

    & Epibiont relationships on hyolithids demonstrated by Ordovician trepostomes (Bryozoa) and Devonian tabulates (Anthozoa). Bull. Geosci. 80, 125–138 (2005)

  10. 10.

    Hyolitha: status of the phylum. Lethaia 13, 21–25 (1980)

  11. 11.

    , & A complete reconstruction of the hyolithid skeleton. J. Paleontol. 88, 160–170 (2014)

  12. 12.

    , & Functional morphology of hyolithids based on flume studies. Veˇstník Cˇeského geologického ústavu. 72, 351–358 (1997)

  13. 13.

    & Skeletal microstructure of helens, lateral spines of hyolithids. Palaeontology 50, 1231–1243 (2007)

  14. 14.

    & The morphology of hyolithids and its functional implications. Palaeontology 48, 1139–1167 (2005)

  15. 15.

    Larval development of hyolithids. Lethaia 11, 293–299 (1978)

  16. 16.

    et al. The operculum and mode of life of the lower Cambrian hyolith Cupitheca from South Australia and north China. Palaeogeogr. Palaeoclimatol. Palaeoecol. 443, 123–130 (2016)

  17. 17.

    & Ecological innovations in the Cambrian and the origins of the crown group phyla. Phil. Trans. R. Soc. Lond. B 371, 20150287 (2016)

  18. 18.

    , , , & A new Burgess Shale-type assemblage from the ‘thin’ Stephen Formation of the southern Canadian Rockies. Geology 38, 811–814 (2010)

  19. 19.

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

  20. 20.

    & Burgess Shale-type preservation of both non-mineralizing and ‘shelly’ Cambrian organisms from the Mackenzie Mountains, northwestern Canada. J. Paleontol. 70, 893–899 (1996)

  21. 21.

    On 20 years of Lophotrochozoa. Org. Divers. Evol. 16, 329–343 (2016)

  22. 22.

    , , & Three-dimensionally preserved digestive systems of two Cambrian hyolithides (Hyolitha). Bull. Geosci. 91, 51–56 (2016)

  23. 23.

    & Structure of the brachiopod lophophore. Paleontol. J. 41, 520–536 (2007)

  24. 24.

    et al. Architecture and function of the lophophore in the problematic brachiopod Heliomedusa orienta (early Cambrian, south China). Geobios 42, 649–661 (2009)

  25. 25.

    et al. Note on the gut preserved in the Lower Cambrian Lingulellotreta (Lingulata, Brachiopoda) from southern China. Acta Zoologica 88, 65–70 (2007)

  26. 26.

    et al. An early Cambrian agglutinated tubular lophophorate with brachiopod characters. Sci. Rep. 4, 4682 (2014)

  27. 27.

    & Early Cambrian ‘soft-shelled’ brachiopods as possible stem-group phoronids. Acta Palaeontol. Pol. 54, 307–314 (2009)

  28. 28.

    Mummpikia gen. nov. and the origin of calcitic-shelled brachiopods. Palaeontology 51, 263–279 (2008)

  29. 29.

    , , , & The scleritome of Eccentrotheca from the Lower Cambrian of South Australia: lophophorate affinities and implications for tommotiid phylogeny. Geology 36, 171–174 (2008)

  30. 30.

    , , , & Evaluating scenarios for the evolutionary assembly of the brachiopod body plan. Evol. Dev. 16, 13–24 (2014)

  31. 31.

    Ciliary sieving and active ciliary response in capture of particles by suspension-feeding brachiopod larvae. Acta Zoologica 86, 41–54 (2005)

Download references


J.M. wrote an initial draft of this paper as part of an unpublished independent undergraduate research report (Research Opportunity Program EEB299Y) under J.B.C.’s supervision at the University of Toronto. We thank B. Lieberman for access to the University of Kansas Natural History Museum collections, S. Lackie for elemental maps, R. Strathmann for images of larval brachiopods (Extended Data Figs 1d and 2e), D. Dufault for drawings and P. Fenton and M. Akrami for collections assistance. Stanley Glacier and Marble Canyon specimens were collected under Parks Canada Research and Collections permits to J.B.C. Funding for this research comes principally from the Royal Ontario Museum and NSERC (Discovery Grant number 341944 to J.B.C.). M.R.S. acknowledges funding from Clare College, Cambridge and the Malacological Society of London. This is Royal Ontario Museum Burgess Shale project number 70.

Author information


  1. Departments of Ecology and Evolutionary Biology and Earth Sciences, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada

    • Joseph Moysiuk
    •  & Jean-Bernard Caron
  2. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK

    • Martin R. Smith
  3. Department of Earth Sciences, Mountjoy Site, Durham University, South Road, Durham DH1 3LE, UK

    • Martin R. Smith
  4. Department of Natural History, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada

    • Jean-Bernard Caron


  1. Search for Joseph Moysiuk in:

  2. Search for Martin R. Smith in:

  3. Search for Jean-Bernard Caron in:


All authors contributed to the examination and interpretation of fossils and the writing of the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Joseph Moysiuk or Jean-Bernard Caron.

Reviewer Information Nature thanks U. Balthasar, M. Martí Mus and M. Sutton for their contribution to the peer review of this work.

Extended data

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    This file contains a Supplementary Discussion and Supplementary References.

Excel files

  1. 1.

    Supplementary Table 1

    This table contains a list of specimens with preserved soft tissues.

  2. 2.

    Supplementary Table 2

    This table contains measured data for Haplophrentis, organised by locality.

About this article

Publication history






Further reading


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.