Mouth and Digestive Tract
Wiwaxia had a pair of arc-shaped bars about 5 mm from the front end of its body (Gould 1989). These bars had a row of simple conical backwards pointing teeth (Gould 1989). These bars are bilaterally symmetrical, which means that if you cut it in half down the long axis, the left and right halves are mirror images of each other. The anterior (front) bar is relatively shorter in length as compared to the posterior bar (Morris 1985). The apex of the arc in the anterior bar is less acute that the posterior (behind the anterior) bar’s (Morris 1985). Each of the bars has a large central tooth with additional smaller teeth flanking it on either side of the bar (Smith 2012). Interestingly, these mouthparts resemble the radulae (rotating teeth) of modern mollusks (Smith 2012).The gut of Wiwaxia was a straight tube that ran along the axis of the body (Smith and Lane 2014).
- Gould, S. J. 1989. Wonderful life. The Burgess Shale and the nature of history. W. W. Norton & Company, New York, NY.
- Morris, S. C. 1985. The Middle Cambrian Metazoan Wiwaxia Corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia, Canada. Philos Trans R Soc Lond B Biol Sci 307:507-582.
- Smith, M. R. 2012. Mouthparts of the Burgess Shale fossils Odontogriphus and Wiwaxia: implications for the ancestral molluscan radula. Proc Biol Sci 279:4287-4295.
- Smith, M. R., and P. Lane. 2014. Ontogeny, morphology and taxonomy of the soft-bodied Cambrian ‘mollusc’ Wiwaxia. Palaeontology 57:215-229.
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