operculum

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operculum

1. Zoology
a. the hard bony flap covering the gill slits in fishes
b. the bony plate in certain gastropods covering the opening of the shell when the body is withdrawn
2. Botany the covering of the spore-bearing capsule of a moss
3. Biology any other covering or lid in various organisms

Operculum

 

the fold of skin that covers the outside of the gill slits in the majority offish (except the shark and ray) and in the larvae of amphibians, especially tadpoles. The operculum of fish of the class Osteichthyes has bones. In the majority offish the operculum plays an active role in breathing: when it is lifted, a vacuum is created in the gill cavity, and water passes from the mouth and pharyngeal cavities into the gill cavity by way of the gill apparatus. It is possible to determine the age of some fish according to the annual rings on the operculum bones.

operculum

[ō′pər·kyə·ləm]
(anatomy)
The soft tissue partially covering the crown of an erupting tooth.
That part of the cerebrum which borders the lateral fissure.
(biology)
A lid, flap, or valve.
A lidlike body process.
References in periodicals archive ?
The objective of this study was to compare the precision of age estimates obtained from the scales, otoliths, opercula, and vertebrae of American shad.
With the recent successes of using opercula in the study of other gastropod fisheries, we surmised that the shape and form of its operculum might provide insight into queen conch age and maturity.
Habib and Robichon (1996) found that dyslexic students from an engineering school had symmetrical opercula and that asymmetry was inversely proportional to performance on a phonological categorization task.
Aging opercula gives insight on the growth and longevity of channeled whelk.
Muma (1989) refined his description of the fixed finger as essentially straight but at times being denticulate, undulate, or serrate and completely lacking a mesal or mesoventral groove, the flagellar setae additionally to include "strong, enlarged, flattened, or hooked" setae, and the female opercula being variable but consistent within species groups.
The animals were undamaged, with normal, attached opercula and no visible shell.
Qurana is also similar to the genera Gudaba and Calcagninus in having a very small and slender body, 2 pairs of tubercles on the abdominal sternite, and short and transverse male opercula, but it is distinguished by the following characters: postclypeus not prominent; rostrum very long, passing center of sternite III (about reaching posterior coxae in Gudaba and just passing posterior coxae in Calcagninus); anterolateral pronotal collar not dentate; hind wing with 6 apical cells (6 in Calcagninus but 5 in Gudaba); male abdomen short (longer than distance from head to cruciform elevation in Calcagninus and Gudaba); and tymbal cover nearly complete (very short in Calcagninus and Gudaba).
Sound produced by timbals can be modified by several anatomical structures such as shape and position of the abdomen, timbal covers, opercula, and tensor muscles that alter quality and intensity of sound emitted (e.
Male genital opercula with numerous setae that are long and curved; anterior operculum with one pair of large slit sensilla; posterior operculum with 8 smaller sensilla.
With its tiny male opercula, this species should not belong to Haphsa or Meimuna but is in an undescribed genus.
Genital opercula with broad anterior arms, recurved medial margin, short, curved wings, posterior margin straight (Fig.