Aperture

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Fig. 1. The aperture and the apertural face (coloured pink) in a biserial form - Textularia aff. goesi Cushman. SEM graphs of specimens from the Gulf of Aqaba, Red Sea. Recent. A-B: apertural (A) and peripheral (B) views of an intact specimen. Note the smooth surfaces characteristic of the faces of many agglutinated forms. a: aperture; af: apertural face; sut: (chamber) suture (Hottinger, 2006; fig. 48 [1] CC/BY-NC-SA)

Definition

  • according to Hottinger (2006):

APERTURE - the primary opening of the foraminiferal shell cavity towards the ambient environment. May be covered by subsequent chambers and thus transformed into a foramen. May be masked (see mask). May be single or multiple.

Remarks: We insist here on restricting the use of the term "aperture" in chambered shells to the ultimate opening of the last chamber cavity into the ambient environment. When a new chamber is added to the previous one as a main process of growth, the aperture is transformed into a means of communication between successive chamber lumina and thus its function changes. The transformed aperture is called a (intercameral) foramen. Its morphology may change through selective resorption of its margins. Often, the last chamber of the shell is not preserved because of its thin walls (see lamellation) and the aperture is lost.

See also

References

Hottinger (2006), Illustrated glossary of terms used in foraminiferal research. Carnets de Géologie, Memoir 2, ISSN 1634-0744

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