One thought on “Tuatara bites

  1. BKC Post author

    Here is some additional information, including a link

    – Mikko

    Not strictly dino-related, but may be of interest:

    Marc E.H. Jones, Paul O’higgins, Michael J. Fagan, Susan E. Evans & Neil
    Curtis (2012) Shearing Mechanics and the Influence of a Flexible Symphysis
    During Oral Food Processing in Sphenodon (Lepidosauria: Rhynchocephalia).
    Anatomical Record (advance online publication)
    doi: 10.1002/ar.22487

    The New Zealand tuatara, Sphenodon, has a specialized feeding system in
    which the teeth of the lower jaw close between two upper tooth rows before
    sliding forward to slice food apart like a draw cut saw. This shearing
    action is unique amongst living amniotes but has been compared with the
    chewing power stroke of mammals. We investigated details of the jaw movement
    using multibody dynamics analysis of an anatomically accurate
    three-dimensional computer model constructed from computed tomography scans.
    The model predicts that a flexible symphysis is necessary for changes in the
    intermandibular angle that permits prooral movement. Models with the
    greatest symphysial flexibility allow the articulation surface of the
    articular to follow the quadrate cotyle with the least restriction, and
    suggest that shearing is accompanied by a long axis rotation of the lower
    This promotes precise point loading between the cutting edges of particular
    teeth, enhancing the effectiveness of the shearing action.
    Given that Sphenodon is a relatively inactive reptile, we suggest that the
    link between oral food processing and endothermy has been overstated. Food
    processing improves feeding efficiency, a consideration of particular
    importance when food availability is unpredictable. Although this feeding
    mechanism is today limited to Sphenodon, a survey of fossil
    rhynchocephalians suggests that it was once more widespread.

    Press Release with video:

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