Cycloid scale


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(Zool.) a fish scale which is thin and shows concentric lines of growth, without serrations on the margin.

See also: Cycloid

References in periodicals archive ?
Oblong scale shape is only present among the males while cycloid scale is in females.
The main part of the body is covered with cycloid scales, but unlike females, males have also ctenoid scales on the head on the eye-side and on the trunk behind the head and close to dorsal and anal fins.
4): cycloid scales tend to be more quadrangular or roundish (Fig.
Scales on body progressively larger posteriorly, scale rows irregular, especially anteriorly; cheek fully covered with small scales; opercle naked except three scales at upper anterior corner; scales cycloid on head and anterodorsally on body, ctenoid posteriorly; scales ventrally on abdomen and chest cycloid; cycloid scales on pectoral-fin base; no scales on fins except for about three rows at base of caudal fin, smaller than last row on caudal peduncle.
When the fish is 10 cm long, it has cycloid scales dorsally on the head only; all other body parts are covered with ctenoid scales.
Scales small for the genus, progressively smaller anteriorly, extending on side of nape to above middle of opercle, but none in median predorsal zone or prepectoral area (if embedded scales are present in these two apparently naked areas, none could be dislodged); scales ctenoid posteriorly on body, becoming cycloid anterior to origin of second dorsal fin; small cycloid scales present on chest; no scales on fins except basal fourth to fifth of caudal fin.
Post-ingestion sample analysis revealed that the many bones and cycloid scales (Moyle & Cech 1988) found in the scat were identical to those of carp (Cyprinus carpio) examined from the SRSU vertebrate collection.
Cirrhitid fishes all have X dorsal spines, III anal spines, 14 pectoral rays (the lower five to seven rays unbranched and thickened), two flat opercular spines, a serrate preopercle, cycloid scales, one to several cirri at the tip of each membrane of the dorsal spines, and no swim bladder.
Antilligobius shares with those genera I,11-15 elements in the second dorsal fin (I,14-20 in Microgobius, Akko, Palatogobius); I,10-15 elements in the anal fin (I,14-21 in Microgobius, Akko, Palatogobius); mostly ctenoid scales on the trunk (few ctenoid scales present in Microgobius, and cycloid scales present in Palatogobius and Akko); scales present on the breast, belly and pectoral fin base (no scales in Microgobius, Akko, Palatogobius); 21-29 scales in the lateral series (35-115 in Microgobius and Akko, 12-17 in Palatogobius); and 6-8 transverse scale rows (19-20 in Microgobius, Akko and none in Palatogobius).
39); no scales on cheek; opercle with single row of 2-3 usually ctenoid scales; pectoral base with usually 3 vertical rows of scales and 4 cycloid scales in posterior row; 5-7-8 ([bar.
Cheek naked or with one or two minute embedded cycloid scales; operculum naked or with 1-5 small embedded cycloid scales.
Operculum and cheek without scales, midline of nape usually naked, but sometimes with 1-5 rows across midline anteriorly, sides of nape scaled to point above posterior end of operculum to posterior end of eye; pectoral base covered with 6-9 cycloid scales in 2 vertical and 4 horizontal rows, posterodorsal 2 scales slightly enlarged, scales often missing in preserved specimens; prepelvic area largely scaled in 5-6 rows of cycloid scales.