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.

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.
References in periodicals archive ?
Dorsal fin bluish-green with 5-7 black vertical bars extending from the base to the medial portion of the fin, interspersed with subtle, yellowish-white bars.
The main characteristics that separate it from other bass is that the upper jaw extends beyond the rear edge of the eye and the first and second dorsal fins have a deep dip between them.
The family Hemiscylliidae, commonly known as bamboo, epaulette, or walking sharks, contains small, slender sharks characterised by nasoral and perioral grooves, short barbels, a small transverse mouth below the eyes, two similar-sized dorsal fins, and a long slender tail.
8 Counts Dorsal fin 23 23-24 20-21 Caudal fin 22 20-22 19-21 Anal fin 24 22-24 21-22 Pelvic fin 5 5 5 Pectoral fin 11 10-11 8-9 Scales in longitudinal series 28 29 Scales in transversal series 12 9 Horizontal scales around caudal 10 16 peduncle
The dorsal outline of the body has a weak convex profile, straight from anterior of the dorsal fin along the caudal peduncle.
boqueronensis has tan or brown stripes on the dorsal fins, a pale pelvic disk and usually a brown stripe of pigment on the lateral midline and B.
0 in upper jaw, its center well behind midpoint of upper jaw; anterior nostrils tubular, elongate, about twice in eye, with small lappet extending from each side; posterior nostrils in upper lip, not visible externally, beginning before eye and ending beneath middle of pupil; upper lip papillate, particularly between anterior and posterior nostrils; broad fleshy chevron dividing snout between anterior nostrils; dorsal fin origin on head, well in advance of gill opening, 1.
The membranes of the dorsal fins are densely speckled with melanophores, except for a half-pupil diameter wide yellow stripe just above the base and, above this, a second but more diffuse yellow stripe.
Dorsal fins narrowly separated; origin of first dorsal fin above tip of cleithral spine; predorsal length 2.