Drass et aL: Larval development of Lut/anus campechanus 



525 



lutjanine larvae, only L. analis simultaneously acquires 

 pigment ventral to notochord flexure. Only the larvae of O. 

 chrysurus and L. synagris develop internal melanophores 

 over the notochord. Both species first acquire this pigment 

 by ~6 mm but it becomes more extensive with develop- 

 ment in O. chrysurus than in L. synagris. Pigment on the 

 dorsal midline of the caudal peduncle develops in all lut- 

 janine larvae except L. griseus. There is some interspe- 

 cific variation in the size when this pigment first develops 

 (Table 5). Rhomboplites aurorubens larvae as small as 4.5 

 mm have dorsal pigment on the caudal peduncle (Richards 

 et al., 1994) and this pigment does not develop in L. analis 

 larvae until ~8 mm. A single melanophore first appeared 

 on the dorsal midline of the caudal peduncle in the 3.8-mm 

 L. campechanus of our series. It was not present in the 

 next two specimens but was present in the 5.5-mm speci- 

 men and all subsequent larvae. 



Interspecific differences among known lutjanine larvae 

 are apparent in the amount, location, and size at first 

 appearance of dorsal-fin pigment. Pigment in the spi- 

 nous dorsal fin first appears in the membrane behind the 

 second spine in i. campechanus. O. chrysurus, L. synagris. 

 and L. analis. Additional melanophores develop posteri- 

 orly behind successive spines in L. synagris throughout 

 flexion, whereas in the other three species, pigment devel- 

 ops posteriorly behind successive spines only in late flex- 

 ion or after flexion. It appears from the illustrations of 

 Clarke et al. (1997) that although pigment between the 

 first and second spines is present in L. synagris from 

 4.7 to 6.2 mm, it is consistently present only in O. chry- 

 surus larvae from preflexion onward. Spinous dorsal-fin 

 pigment in L. grLseus differs notably from the other spe- 

 cies of lutjanines; melanophores first form low in the 

 fin at the base of the second or third spines, or at the 

 base of both, and as development proceeds, melanophores 

 are added distally (farther out onto the fin) and posteri- 

 orly. Pigment was present between the second and third 

 dorsal-fin spines in the few R. aurorubens larvae that 

 had intact dorsal-fin membranes. Dorsal-fin pigment was 

 not indicated in illustrations by Laroche ( 1977), probably 

 because these specimens did not have intact fin mem- 

 branes. Among known GOM lutjanine larvae, only L. syn- 

 agris larvae develop pigment in the second (soft) dorsal 

 fin before ray formation is complete, at ~6 mm. In larvae 

 of the remaining species, pigment in the second dorsal-fin 

 first appears at larger sizes when fin ray development is 

 well advanced (Table 5). 



Anal- and pelvic-fin pigmentation is also useful in sepa- 

 rating the larvae of GOM lutjanines. Pigment on the anal- 

 fin base develops in all six species whose larvae have been 

 described and of these, L. campechanus larvae develop this 

 pigment at the smallest size, <4 mm (Table 5). There are 

 greater differences among larvae in size at first appear- 

 ance of pigment in the anal-fin membrane than in the 

 anal base. Lutjanus campechanus and L. analis larvae can 

 be distinguished from the other described larvae by later 

 development of anal-fin pigment at sizes >12 mm (Table 

 5). Pigment on the pelvic fin bud has been indicated in all 

 illustrated lutjanine larvae except L. griseus. It is likely 

 that this exception is due, not to true absence of this fea- 



ture in L. griseus, but to the limited number of larvae in 

 the described series (Richards and Saksena, 1980). The 

 4.2-mm L. griseus larva illustrated by these authors had 

 pigment at the distal tips of the pelvic fin, but this pigment 

 was not present in larger larvae of the series or in the 

 7.1-mm specimen illustrated in Richards et al. ( 1994). Pel- 

 vic-fin pigment distinguishes O. chrysurus and L. griseus 

 from other lutjanine larvae once the spine and first ray 

 are formed. From illustrations in Clarke et al. (1997), it 

 appears that starting in the preflexion stage, O. chrysurus 

 larvae have pigment throughout the pelvic-fin membrane 

 and not just around the first fin ray as in L. campecha- 

 nus, L. synagris, and L. analis. The unique condition of 

 pelvic-fin pigmentation that characterizes L. griseus is the 

 "candycane stripe" pattern of melanophores that overlay 

 the pelvic spine. Pigment on the pelvic spine is present in 

 L. griseus larvae as small as 4.2 mm and the striped pat- 

 tern is evident by at least 6.2 mm (Richards and Saksena, 

 1980). 



In Table 9 of their recent publication, Clarke et al. ( 1997) 

 provided a summary of distinguishing characters for the 

 known larvae and juveniles of western Central Atlantic 

 lutjanine snappers. We have noted some discrepancies in 

 that summary that may cause confusion for those attempt- 

 ing to identify lutjanine snapper larvae from our area. In 

 Table 9, the "usual" number of pav melanophores listed for 

 L. campechanus was given as 16-18. The modal number of 

 pav spots among preflexion L. campecha?jus larvae (2.2-3.8 

 mm BL; /7=7G) from the GCRL rearings was 15, and 50 

 specimens had 14 to 19 pav spots. Also in Table 9, for the 

 character "serrations on dorsal and pelvic fin spines," the 

 entry for L. campechanus states, "on anterior spine margin 

 only." Larvae of L. campechanus develop serrations on the 

 anterior margin of the pelvic spine only, not on the dorsal 

 spines (Collins et al., 1980; Potthoff et al, 1988). Clarke 

 et al. ( 1997) also note that L. griseus larvae develop inter- 

 nal melanophores ventral to the point of notochord flexure 

 (their character "O"). This feature is not visible in any of 

 the published illustrations of L. griseus larvae or in speci- 

 mens we have examined. Finally, information in Table 9 

 that pertains to character "P" — "internal melanophores on 

 antero-ventral surface of gut (peritoneum! dorsal to pelvic 

 bone" noted as being absent in four species — was clearly 

 present in the R. aurorubens and L. campechanus larvae 

 that we examined and is visible in illustrations of L. analis 

 and O. chrysurus in Clarke et al. ( 1997). 



The descriptions of larval lutjanine snapper develop- 

 ment now available will allow scientists to identify mid- 

 to late-flexion and postflexion larvae of the most common 

 lutjanids in the Gulf of Mexico. In an examination of over 

 1500 snapper larvae from Gulfwide collections in 1992 

 and 1993, we found that the larvae of R aurorubens, L. 

 campechanus, and P. aquilonaris made up 237^, 13*7^, and 

 13% of all snapper larvae captured, respectively. Other 

 identified taxa consisted of Lutjanus spp. (37f ), L. griseus 

 (<l'7f), and L. synagris (<l'7r). However, 47*^ of snapper 

 larvae in these collections, typically <3. 5-4.0 mm in length, 

 could not be identified beyond the family level because 

 diagnostic characters are present only after flexion has 

 begun. 



