BIROn - Birkbeck Institutional Research Online

    Cutting blade dentitions in squaliform sharks form by modification of inherited alternate tooth ordering patterns

    Underwood, Charlie J. and Johanson, Z. and Smith, M.M. (2016) Cutting blade dentitions in squaliform sharks form by modification of inherited alternate tooth ordering patterns. Royal Society Open Science 3 , ISSN 2054-5703.

    [img] Text
    Underwood et al squaliform.pdf - Author's Accepted Manuscript
    Restricted to Repository staff only

    Download (6MB)
    16648.pdf - Published Version of Record
    Available under License Creative Commons Attribution.

    Download (2MB) | Preview


    The squaliform sharks represent one of the most speciose shark clades. Many adult squaliforms have blade-like teeth, either on both jaws or restricted to the lower jaw, forming a continuous, serrated blade along the jaw margin. These teeth are replaced as a single unit and successor teeth lack the alternate arrangement present in other elasmobranchs. Micro-CT scans of embryos of squaliforms and a related outgroup (Pristiophoridae) revealed that the squaliform dentition pattern represents a highly modified version of tooth replacement seen in other clades. Teeth of Squalus embryos are arranged in an alternate pattern, with successive tooth rows containing additional teeth added proximally. Asynchronous timing of tooth production along the jaw and tooth loss prior to birth cause teeth to align in oblique sets containing teeth from subsequent rows; these become parallel to the jaw margin during ontogeny, so that adult Squalus has functional tooth rows comprising obliquely stacked teeth of consecutive developmental rows. In more strongly heterodont squaliforms, initial embryonic lower teeth develop into the oblique functional sets seen in adult Squalus, with no requirement to form, and subsequently lose, teeth arranged in an initial alternate pattern.


    Item Type: Article
    Keyword(s) / Subject(s): sharks, Squalus, squaliforms, evolution of teeth, replacement pattern
    School: Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences
    Research Centres and Institutes: Earth and Planetary Sciences, Institute of
    Depositing User: Charles Underwood
    Date Deposited: 01 Feb 2017 17:07
    Last Modified: 02 Aug 2023 17:27


    Activity Overview
    6 month trend
    6 month trend

    Additional statistics are available via IRStats2.

    Archive Staff Only (login required)

    Edit/View Item Edit/View Item