Porca | Glossary - Diatoms of North America

Porca

A porca is a transapical undulation, or elevated ridge, of the external valve face in the genus Surirella. In Latin, porca is an agricultural term meaning the ridge between two furrows. The plural is porcae.

Alternative Terms

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

Publication Link: 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.

Publication Link: 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.

Publication Link: 10.1080/0269249X.2012.739975
Veselá, J., Johansen, J.R. and Potapova, M. (2013) Surirella terryi and S. cruciata: two rare diatoms in North America Diatom Research

Publication Link: 10.1080/0269249X.2013.853697

25 E Publ Copy — External surface of a species of Surirella (SEM). A porca is outlined in white. Two porcae are visible in the image.

Gs020021 19 — External surface of Surirella amphioxys (SEM). The raised portion of the undulation is a porca. The raised canal (keel) containing the raphe is at the top of the image.