Porca
A term applied to a particular structure in the genus Surirella. Porcae are transapical undulations, or elevated ridges, of the external valve face.
Alternative Term
ridge surface
corrugation ridge
transapical valve undulation
Citations
Bramburger, A.J., Haffner, G.D., Hamilton, P.B., Hinz, F. and Hehanussa, P.E. (2006). An examination of species within the genus Surirella from the Malili Lakes, Sulawesi Island, Indonesia, with descriptions of 11 new taxa. Diatom Research 21(1): 1-56. 10.1080/0269249X.2006.9705650
Karthick, B., Hamilton, P.B. and Kociolek, J.P. . (2012). Taxonomy and biogeography of some Surirella Turpin (Bacillariophyceae) taxa from Peninsular India. Nova Hedwigia, Beiheft 141: 81–116. 1438-9134/2012/0141 - 0081
Van de Vijver, B., Cocquyt, C., de Haan, M., Kopalová, K. and Zidarova, R. (2012). The genus Surirella (Bacillariophyta) in the sub-Antarctic and maritime Antarctic region. Diatom Research 28: 92-108. 10.1080/0269249X.2012.739975
Image Credit: Jana Veselá
Scanning electron micrograph of the external surface of a species within Surirella. A porca is outlined in white; a total of 2 porcae are visible in the image.
Image Credit: Marina Potapova
Scanning electron micrograph of the external surface of Surirella amphioxys. The raised portion of the undulation is a porca. The raised canal containing the raphe is at the top of the image.