CHAO and MUSICK: LIFE HISTORY OF JUVENILE SCI AENID FISHES 



lae move forward (Figure 20C). The relative size 

 of the mouth opening in B. chrysoura (Table 5) is 

 similar to C. regalis. The anterior view of its 

 mouth opening shows equal upper and lower jaws 

 (Figure 20c, c'). Although B. chrysoura feeds an- 

 teriorly, a pelagic feeder, its stomach contents are 

 similar to those of C. regalis (Figure 29), except for 

 a smaller proportion of fishes. The jaw teeth of B. 

 chrysoura are strong, conical, and arranged in 

 narrow bands, but canines are absent at the tip of 

 the premaxilla (Figure 22C). Its pharyngeal teeth 

 are relatively stronger and blunter than in C. re- 

 galis (Figure 23B, C), especially along the median 

 rows. Gill rakers of B. chrysoura are intermediate 

 between L. fasciatus and C. regalis in number 

 (Table 6) and length (Figure 24A-C). The intes- 

 tine of B. chrysoura has two loops and its relative 

 length and number of pyloric caeca (6-8) are also 

 intermediate between L. fasciatus and C. regalis 

 (Figure 25C; Tables 7, 8). These intermediate fea- 

 tures reflect the intermediate feeding habits of B. 

 chrysoura (Figure 29). In addition, the body shape 

 of B. chrysoura is oblong (Figure 28C) and not 

 fusiform as in C. regalis, thus resulting in slower 

 swimming and less efficiency in capturing fishes, 

 as reflected in the diet. The relatively well- 

 developed cephalic pore systems of B. chrysoura 

 (Figure 26C), three upper and five marginal pores 

 on the snout and six mental pores on the tip of the 

 lower jaw, also may indicate that B. chrysoura 

 depends more on "taste" feeding lower in the water 

 column than L. fasciatus and C. regalis. 



Micropogonias undulatus, Leiostomus xan- 

 thurus, and Menticirrhus saxatilis have inferior 

 mouths (Figure 20D-F) and rather protrusible 

 premaxillae (Figure 21D-F). These features en- 

 able them to feed anteriorly and ventrally to their 

 body axis along their swimming courses. Their 

 mouths open as the lower jaws drop ventrally 

 backward and the premaxillae protrude antero- 

 ventrally (Figure 20D-F'). Their mouths are rel- 

 atively smaller than those of the pelagic feeders 

 described previously (Table 5). The anterior views 

 of their mouths ( Figure 20d, d ', e, e ', f, f ' ) show that 

 the upper jaws (premaxillae) are shorter or equal 

 to the lower jaws (dentaries). Although they all 

 feed anteroventrally and benthically, there are 

 differences in their feeding habits (Figure 29). 

 These differences are reflected in the structural 

 differences in the feeding apparatus and feeding 

 behavior among them. The jaw teeth of M. sax- 

 atilis, Micropogonias undulatus , and L. xanthur- 

 us are all set in bands and the outer row of teeth on 



the upper jaws and an inner row of teeth on the 

 lower jaws are slightly enlarged (Figure 22D-F). 

 The pharyngeal teeth of M. undulatus and Men- 

 ticirrhus saxatilis are conical (Figure 23D, E) and 

 the median rows are larger and blunt. Leiostomus 

 xanthurus has smaller pharyngeal teeth and the 

 median ones are molariform (Figure 23F). The gill 

 rakers of these three bottom feeding sciaenids dif- 

 fer in number (Table 6) and size (Figure 24D-F). 

 Menticirrhus saxatilis has the fewest and shortest 

 gill rakers among them. Micropogonias undulatus 

 has fewer but longer gill rakers than L. xanthurus. 

 The inner gill rakers of L. xanthurus are longest 

 (Figure 24f) and most numerous (Table 6). This is 

 reflected in the larger numbers of small crusta- 

 ceans (e.g., copepods) ingested by L. xanthurus 

 (Table 14). The relative length of intestines (Table 

 7) and their in situ position (Figure 25D — F) are 

 similar among these benthic feeders. The average 

 relative intestinal length of M. undulatus and 

 Menticirrhus saxatilis is slightly shorter than in 

 L. xanthurus (Table 7). The numbers of pyloric 

 caeca of these bottom feeders are similar ( Table 8). 

 The cephalic pore and barbel system differ among 

 Micropogonias undulatus , L. xanthurus, and Men- 

 ticirrhus saxatilis. They all have five upper and 

 five marginal pores on the tip of snout (Figure 

 26D-F). Micropogonias undulatus and Menticir- 

 rhus saxatilis also have a deeply notched rostral 

 fold. Ventrally, Micropogonias undulatus has five 

 pores and six miniature barbels (Figure 26d); 

 Menticirrhus saxatilis has four pores and a short 

 rigid barbel with an apical pore (Figure 26e); L. 

 xanthurus has five pores and no barbel (Figure 

 26f). Menticirrhus saxatilis also has the most pro- 

 nounced snout and most elongate and rounded 

 body form (Figure 28E). Leiostomus xanthurus 

 has the least pronounced snout and shortest and 

 deepest body form (Figure 28F). Micropogonias 

 undulatus is intermediate in snout and body form 

 between Menticirrhus saxatilis and L. xanthurus. 

 The length of snout and body form reflect the 

 feeding habits of these three species. Food habits 

 (Figure 29) indicate that M. saxatilis and Micro- 

 pogonias undulatus feed on the substrate, on the 

 epifauna, more than they feed "into" the substrate 

 on the infauna. Leiostomus xanthurus feeds more 

 on the infauna. The long projecting snout seems to 

 be an obstacle for fishes with an inferior mouth to 

 forage into the bottom for food. Roelofs' (1954) 

 observations on feeding behavior of M. undulatus 

 and L. xanthurus in aquaria with sandy bottoms 

 were repeated during the present study. Juveniles 



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