dorsal fin

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dorsal fin

[′dȯr·səl ′fin]
(vertebrate zoology)
A median longitudinal vertical fin on the dorsal aspect of a fish or other aquatic vertebrate.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

dorsal fin

dorsal fin
An additional fin surface along the top of the fuselage just in front of the main fin. Dorsal fins help increase directional stability, especially at high air speeds and Mach numbers.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
Caption: First dorsal fin originating over pectoral fins
Images of dolphin dorsal fins, flukes and bodies taken during photo-identification studies offer a great tool to assess presence of barnacles (Speakman et al.
The count of scales in longitudinal series is made from just behind the upper end of the gill opening (not including two or three small anterior scales) to the base of the caudal fin (not including a smaller scale that overlaps the fin base); scales in transverse series are counted from the origin of the anal fin obliquely upward to the base of the first dorsal fin; gill-raker counts were made on the first gill arch, the rakers on the upper limb listed first (only one or two counts of paratypes per species).
Three broad vertical bands become apparent dorsally on the nape, below the center of the spinous dorsal fin and below the center of the soft dorsal fin by 13.5 mm.
Mature fish show bright turquoise coloring on the belly, breast and cheeks, and then have a shallow dip between the dorsal fins. The Suwannee bass originally was found in only the Suwannee and Ochlocknee river systems, but it's been moved to a number of other northwest river systems.
Secondary sexual dimorphism: Males with reduced hooks on each branched rays of anal, pelvic, pectoral and dorsal fins. With a row of hooks at each branched ray of pelvic fins.
The count of scales in longitudinal series is made from above the upper end of the gill opening to the base of the caudal fin; scales in transverse series are counted from the origin of the anal fin obliquely upward to the base of the first dorsal fin; the count of gill rakers is made on the first gill arch, those on the upper limb given first.
CP = caudal peduncle; horizontal distance from the posterior edge of the dorsal fin base to the posterior edge of the hypural plate.
Colour in life: Juveniles brown dorsally, grading to pale yellow on side of body with series of 10, large red-brown squares in midlateral row; pair of oblique brown bands from lower rear corner of eye to lower margin of operculum; additional brown stripe just above and parallel to previous pair, crossing opercle and joining dark brown triangular mark on pectoral-fin base; fins translucent to slightly dusky with 3 large reddish spots at base of second dorsal fin, and smaller reddish brown spots on remainder of fin and faint spotting on caudal fins; pelvic fin white and pectoral fins translucent.
It is possible that some small dorsal fins may have been anal fins or second dorsal fins.
9): head and body dull orange-red, grading to brownish yellow on snout and to yellow posteriorly on caudal peduncle; dorsal fins with whitish rays, translucent membranes, and yellow along base; caudal and pectoral fins with light yellow rays and translucent membranes; orbit rimmed in reddish; iris reddish gray.
The color pattern of the body, with the alternated blue and reddish brown bars, the absence of filaments at the tip of anal and dorsal fins, and the small iridescent blue single spots present in females body are autapomorphies of Spectrolebias pilleti within the genus Spectrolebias.

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