FISHERY BULLETIN: VOL. 78. NO. 3 



sociated with three elements (Figure 9). It was 

 secondarily associated with the first two spines 

 and serially associated with the first ray. All other 

 pterygiophores were serially associated with one 

 anal fin ray and secondarily associated with a pre- 

 ceding ray. In the largest specimen (48.0 mm SL) a 

 stay was associated with the last anal fin 

 pterygiophore. 



The number of anal fin pterygiophores between 

 haemal spines was highly variable. The first 

 pterygiophore, however, always occurred, singly, 

 between the last precaudal vertebra (number 10) 

 and the first caudal vertebra (number 11) (Table 4). 



Anal fin pterygiophores were first observed at 

 5.5 mm SL (Figure 8). Development began be- 

 tween haemal spines 3 and 4 and proceeded an- 

 teriorly and posteriorly simultaneously. Develop- 

 ment was rapid. The adult complement was 

 reached at 6.3 mm SL. 



Table 4. — Frequencies of anal fin pterygiophores between 

 haemal spines in 30 Leiostomus xanthurus (5.7-40.8 mm SL). 



Figure 9. — Arrangement of the first four anal fin pterygio- 

 phores in relation to haemal spines for Leiostomus xanthurus 

 (19.6 mm SL). Prl, pterygiophore in serial association with the 

 first anal fin ray; Hsll, the first haemal spine on the 11th cen- 

 trum; S, anal spine; R, anal ray. 



Other Structures 



Centra were not fully differentiated until ca. 9 

 mm SL, but the adult complement of vertebrae 

 (25, including urostyle) was determined from lar- 

 vae as small as 4.6 mm SL by counting combina- 

 tions of neural spines and myosepta (Figure 10 A). 

 Precaudal vertebrae (10) were differentiated from 

 caudal vertebrae (15) in larvae as small as 5.1 mm 

 SL (Figure lOB). The first caudal vertebra was 

 easily identified as its haemal spine was approxi- 

 mately three times longer than the preceding 

 parapophysis. 



Haemal 



spine 



number 



No of pterygiophores 

 between tiaemal spines 



12 3 



Haemal 



spine 



number 



10-11 — 30 — — 14-15 



11-12 19 10 1 — 15-16 



12-13 — 9 21 — 16-17 



13-14 — 1 29 — 17-18 



One important adult characteristic of the genus 

 Leiostomus is an entire preopercular margin. Spot 

 larvae and early juveniles, however, exhibited 

 preopercular, subopercular, and interopercular 

 spines (Figure 11). Preopercular spines formed 

 first (4.4 mm SL). They occurred in two rows, one of 

 weak lateral spines and one of stouter marginal 

 spines. Preopercular spines increased during on- 

 togeny, but juveniles eventually lost these spines. 

 Interopercular and subopercular spines are less 

 important characters for larval identification be- 

 cause they formed during the late larval period 

 (Figure 11). They also were lost during the early 

 juvenile stage. 



Branchiostegal rays appeared early in develop- 

 ment and attained the adult complement (7), 

 shared by all sciaenids, at 6.3 mm SL (Table 1). 



Spot have a high number of gill rakers among 

 sciaenids ( 29-36, Chao and Musick 1977), but since 

 the adult complement was not attained until a 

 large size was reached (Table 1), total gill raker 

 counts were not considered to be a good diagnostic 

 character. The full complement of gill rakers on 

 the ceratobranchial, however, was obtained at ca. 

 13 mm SL. 



Pigmentation 



Newly hatched larvae were inconspicuously 

 pigmented (Figure 2). An ill-defined row of faint 

 melanophores on the anterior portion of the body 

 extended from the anterodorsal surface of the 

 head to the ventrolateral surface of the trunk. 

 Posterior to the anus on the dorsal midline, there 

 were about two to five faint punctate melano- 

 phores. Faint melanophores occurred on the an- 

 terodorsal surface of the oil globule. 



Shortly after hatching (ca. 1 d), a characteristic 

 pattern began to form on the body. Initially, on 

 almost all larvae, there was a faint dorsal and 

 ventral melanophore opposite each other, located 

 about midbody. In addition, there were other faint 

 melanophores which, initially, occurred mainly on 

 the dorsal midline. With larval growth, there were 



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