Pseudoloculus

A pseudoloculus is a chambered areola that opens to the valve exterior through a large foramen and is covered on the valve interior by a type of velum. (By contrast, the positions of the foramen and the velum in a loculus are reversed.) Plural is pseudoloculi. Typically, pseudoloculi are hexagonal in outline, are distributed regularly across the valve face, and have vela with an equal number of pores.

Example genera with pseudoloculi include Endictya, Thalassiosira, Triceratium sensu stricto, Stephanopyxis, and the fossil genus Gladius.

See also areola, loculus, and false pseudoloculus.

Citations

Sims, P.A., Williams, D.M. and Ashworth, M. (2018) Examination of type specimens for the genera Odontella and Zygoceros (Bacillariophyceae) with evidence for the new family Odontellaceae and a description of three new genera. Phytotaxa 382: 1-56

Publication Link: 10.11646/phytotaxa.382.1.1
Ross, R., Cox, E.J., Karayeva, N.I., Mann, D.G., Paddock, T.B.B., Simonsen, R. and Sims, P.A. (1979) An amended terminology for the siliceous components of the diatom cell Nova Hedwigia, Beihefte 64: 513-533
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.

Endictya oceanica 012 — External view of *Endictya oceanica* (SEM). Pseudoloculi are shown with hexagonal foramina on the outside of the chambers at the top of image and with the porous layer on the inside at bottom of image. Scale bar = 2 µm.

Stephanopyxis turris 04 — External view of *Stephanopyxis turris* (SEM). Pseudoloculi are shown with the hexagonal foramina opening to the outside of the chambers and the porous layer on the inside appearing in the frames of the foramina. Scale bar = 5 µm.