Ontogeny, morphology and taxonomy of the soft‐bodied Cambrian 'mollusc' Wiwaxia. (20th August 2013)

• Record Type: Journal Article
• Authors: Smith, Martin R.; Lane, Phil
• Is Part Of: Palaeontology. Volume 57:Part 1(2014:Jan.)
• Page Start: 215
• Page End: 229
• Publication Date: 2013-08-20
• Subjects: Paleontology -- Periodicals; 560
• DOI: 10.1111/pala.12063
• Languages: English
• ISSNs: 0031-0239

Abstract

<abstract abstract-type="main" id="pala12063-abs-0001"> <title>Abstract</title> <p>The soft‐bodied Cambrian organism <italic>Wiwaxia</italic> 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 <italic>Wiwaxia</italic>'s sclerites and scleritome. My observations illuminate the diversity within the genus and demonstrate that <italic>Wiwaxia</italic> 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 <italic>Wiwaxia</italic>, solidifying its relationship with the contemporary <italic>Odontogriphus</italic>. Similarities between the scleritomes of <italic>Wiwaxia</italic>, halkieriids, Polyplacophora and Aplacophora hint that the taxa are related. A molluscan affinity is robustly established, and <italic>Wiwaxia</italic> provides a good fossil proxy for the ancestral aculiferan – and perhaps molluscan – body plan.</p> </abstract>