hypural


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hypural

[hī′pyu̇r·əl]
(vertebrate zoology)
Of or pertaining to the bony structure formed by fusion of the hemal spines of the last few vertebrae in most teleost fishes.
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As the caudal rays developed, less prominent spots appeared in the middle of the hypural margin (Fig.
For example, when using standard length, determination of where the caudal peduncle ends greatly depends on the individual reader and where they feel the hypural bone ends.
Seven larvae and one juvenile from this group of specimens were cleared and stained (Potthoff, 1984) and identified as Symphurus oligomerus on the basis of meristic characters (dorsal-fin rays, anal-fin rays, caudal-fin rays, total vertebrae, and hypural bones) and interdigitation of dorsal-fin pterygiophores and neural spines (ID pattern), which was 1-3-2-2-2 (Mahadeva and Munroe, 1990; Munroe, 1992; Munroe et al.
As evidenced by the formation of hypural elements, notochord flexion was first observed at 10 to 12 DAH in the first two rearing trials.
The caudal skeleton consisted of one ural centrum, preural centra, neural and haemal spines, three epurals, two uroneurals, one superior hypural ([HY.
Lengths given for specimens are standard length (SL), the straight-line distance from the front of the upper lip to the base of the caudal fin (posterior end of the hypural plate).
Early-flexion begins at hatching, mid-flexion begins with the formation of the forth hypural and epurals, and late flexion begins with the development of the fifth hypural and ends with complete notochord flexion.
Methods used for taking counts and measurements follow those described and figured by Miller and Lea (1972:7-12), with the following additions: interorbital width is measured between lateral margins of the frontal bones at their narrowest widths; head depth is measured at mid-orbit; first infraorbital pore width is measured at the greatest width, anterior to posterior; all gill-raker counts are taken from the first arch; dorsolateral scale-row counts include all scales (or fused clusters of scales) with enlarged plate-like bases; lateral-line scale counts also include scales that occasionally extend beyond the posterior margin of the hypural plate.
9/8 or 9/7) is the number of segmented caudal rays attaching to the upper and lower hypural plates respectively.
All individuals collected were postflexion, prejuvenile, or juvenile stage as defined in Leis and Rennis (1983), and standard length (SL) was measured as the distance from the tip of the snout along the midline to a vertical line through the posterior edge of the hypural plate.
The caudal fin skeleton is of generalized gobioid morphology, with two epurals, fused hypurals 1 plus 2 and 3 plus 4, and a small separate hypural 5.