9 II 9 7 Adults II-III 8-10 7 Caudal-fin rays Body length Total range (mm) myomeres
Vertebrae Upper Lower 2.
On day 49, the single row of dorsal midline pigment extended to 5-6 myomeres anterior to the caudal peduncle.
At time of hatching, the completed series consisted of a light irregular line of melanophores at 50% BL, larger and more closely spaced melanophores at 60-80% BL, and ended 1-2 myomeres anterior to the terminus of the dorsal midline series (Fig.
Pseudopercis semifasciata larvae were distinguished from other larvae by the modal number of myomeres
(between 36 and 38), their elongated body, the size of their gut, and by osteological features of the neuro- and branchiocranium.
The number of vertebrae, which should approximate the number of myomeres
in larvae much smaller than those collected in this study, in conjunction with pigment differences have been shown to be useful in separating clupeid species complexes (Ditty et al.
Despite the difficulty in counting myomeres
, either the number of vertebrae in cleared and stained specimens or the number of myomeres
between the pectoral-fin base and anus (usually three less than the number of precaudal vertebrae; see Tables 2 and 4) revealed a consistent difference between both species.
Pigment patterns, especially the position of body melanophores in relation to myomeres
, were determined for specimens from 3 to 16 days after hatching (n=180, 3.
Postanal pigment present as melanophores along distal edges of dorsal and anal finfolds; four distinct pigment areas along the dorsal midline, anterior (first) spot begins 1-5 myomeres
after anus at about myomere
12-16, second spot begins at about myomere
23-26, third spot begins at about myomere
33-46, and the fourth spot begins at about myomere
41-42 (after initially forming as a dorsal midline patch, the posteriormost spot coalesces with ventral patch to form a caudal bar); series of melanophores from the gut along the ventral midline beginning in a double row, changing to a single row posterior to the ventral stripe of the caudal bar; several additional melanophores along the ventral midline posterior to the caudal bar, pigment above and below the tip of the notochord.
Another characteristic of chordates are myomeres
, blocks of muscle tissue often arranged in a zig-zag pattern.
The number of myomeres
distinguishes species: Indonesian leptocephali have about 10 fewer myomeres
than the 112 to 118 typical of Japanese larvae.
0 mm BL) typically have three equidistant blotches on the distal margin of the dorsal fin fold, located approximately between myomeres
6-9, 16-19, and 28-33, and an additional blotch located on the dorsal margin of the body between myomeres
28 and 33.
The larvae of both are characterized by having 24-25 myomeres
, a large triangular gut (54-67% of BL) in postflexion larvae, small spines on the preopercle and interopercle, a smooth supraocular ridge, a small to moderate gap between the anus and the origin of the anal fin, and distinctive pigment patterns.