Fibulae
Internal struts that provide structural support to the canal that contains the raphe. The fibulae extend transapically from the raphe canal to the valve face and are found in a number of genera including Denticula, Nitzschia and Surirella.
Alternative Term
keel puncta
Citations
Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.
Image Credit: Sarah Hamsher
An internal view of a valve of Nitzschia kurzeana, showing the fibulae.
Image Credit: Sarah Hamsher
An LM image of Nitzschia kurzeana, showing the fibulae.
Image Credit: Jonathan English
Surirella ovalis possesses fibulae that support the marginal raphe canal. Note that fibulae should not be confused with costae.