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Article: Ontogeny, morphology and taxonomy of the soft-bodied Cambrian 'mollusc' Wiwaxia

Publication: Palaeontology
Volume: 57
Part: 1
Publication Date: January 2014
Page(s): 215 229
Author(s): Martin R. Smith
Addition Information

How to Cite

SMITH, M. R. 2014. Ontogeny, morphology and taxonomy of the soft-bodied Cambrian 'mollusc' WiwaxiaPalaeontology57, 1, 215–229, doi: 10.1111/pala.12063

Author Information

  • Martin R. Smith - Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada (email:
  • Martin R. Smith - Palaeobiology Section, Department of Natural History, Royal Ontario Museum, Toronto, Ontario, Canada

Publication History

  • Issue published online: 6 JAN 2014
  • Article first published online: 20 AUG 2013
  • Manuscript Accepted: 25 MAY 2013
  • Manuscript Received: 26 SEP 2012

Funded By

Natural Sciences and Engineering Research Council of Canada Discovery Grant
University of Toronto
Geological Society of America

Online Version Hosted By

Wiley Online Library (Free Access)
Get Article: Wiley Online Library [Free Access]


The soft-bodied Cambrian organism Wiwaxia poses a taxonomic conundrum. Its imbricated dorsal scleritome suggests a relationship with the polychaete annelid worms, whereas its mouthparts and naked ventral surface invite comparison with the molluscan radula and foot. 476 new and existing specimens from the 505-Myr-old Burgess Shale cast fresh light on Wiwaxia's sclerites and scleritome. My observations illuminate the diversity within the genus and demonstrate that Wiwaxia did not undergo discrete moult stages; rather, its scleritome developed gradually, with piecewise addition and replacement of individually secreted sclerites. I recognize a digestive tract and creeping foot in Wiwaxia, solidifying its relationship with the contemporary Odontogriphus. Similarities between the scleritomes of Wiwaxia, halkieriids, Polyplacophora and Aplacophora hint that the taxa are related. A molluscan affinity is robustly established, and Wiwaxia provides a good fossil proxy for the ancestral aculiferan - and perhaps molluscan - body plan.

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