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n.1.(Anat.) The anterior opercular bone in fishes.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
--Preopercular pores (pr.p), there were five: two (pr.p 1, 2) over the lower portion of the preoperculum curvature, and the last three pores (pr.p 3, 4, 5), were arranged in a straight line to the edge (the upper portion of the preoperculum) of the same bone (Fig.
During the study comparative age determinations were performed on a total of 243 fish samples by using the operculum suboperculum preoperculum interoperculum and vertebrae bony structures.
Posterior margin of preoperculum with 20 (16-28) very fine serrae; margins of posterior and ventral edges of preoperculum free to about level of middle of pupil.
There are two to three pre-anal pigments and 16 post-anal pigments in the ventral midline; cephalic pigments are present from the postflexion stage, as well as a serrated preoperculum. The prejuvenile and juvenile organisms are distinguished by their body depth, the anal-fin formula, the serrated preoperculum and the base pigments in the dorsal and anal fins.
Embedded melanophores appeared in the lateral muscle at 4.49 mm BL (Table 6), upper jaw tip at 5.47 mm BL, operculum and preoperculum at 6.18 mm BL, the membrane of the first dorsal fin at 6.32 mm BL, forebrain at 6.83 mm BL, and the cleithral symphysis at 10.79 mm BL.
The new taxon is the only member of the genus possessing scales on the preoperculum (cheek) and also three scales on the upper anterior corner of the operculum.
However, the new species differs in several key features that appear to preclude its inclusion, particularly the serrate interoperculum (smooth in Apolemichthys) and the multispined preoperculum (only one spine in Apolemichthys).
Eleotris), lacking lateral-line sensory pores and having a wide gill opening (to below preoperculum).
In particular, the predorsal region, the posterior half of the preoperculum and the operculum are typically more heavily damaged than other regions.
Preoperculum long, distance from end of eye to upper posterior preopercular subequal to distance from snout to an eye length behind eye.
In specimens from the Great Barrier Reef, the orange bar on the preoperculum is much narrower than in specimens from other areas, although specimens from the Coral Sea have a broad bar, similar to that in specimens from non-Australian localities.
Preoperculum with 17 (16-23) serrae, including enlarged spine at preopercular angle; opercular spine flat, broad-based, slight double curvature, roughly forming equilateral triangle with concave sides and thickened centre, less than pupil diameter in length, not extending beyond opercular membrane.