TUCKER: LARVAL DEVELOPMENT OF CITHARICHTHYS AND ETROPUS 



men in which caudal centra could be counted was 

 5.8 mm NL (midflexion). 



The second, third, and fourth dorsal rays are 

 elongate and widely separated at the bases from 

 preflexion (about 4 mm NL) through transfor- 

 mation (17.4 mm SL). During early caudal 

 formation (5.0 mm NL), rays near the middle of 

 the dorsal fin begin to calcify. Calcification pro- 

 ceeds anteriorly and posteriorly. Adult counts 

 are present from late flexion (6.4 mm NL) on- 

 ward. The first ray and the most posterior rays 

 are calcified just prior to transformation (17.4 

 mm SL). 



During early caudal formation (5.0 mm NL), 

 anal rays near the middle of the fin begin to cal- 

 cify. Calcification proceeds anteriorly and pos- 

 teriorly. Adult counts are present from late 

 flexion (about 8 mm NL) onward. The most pos- 

 terior rays are calcified just prior to transforma- 

 tion (17.4 mm SL). 



Development of the left pelvic fin precedes 

 that of the right fin. The left pelvic fin bud ap- 

 pears during preflexion (3.7 mm NL). Rays 

 develop between preflexion (4.0 mm NL) and 

 late flexion (about 8.9 mm NL). The most ante- 

 rior two rays are the first to appear; the second is 

 elongate and the first slightly elongate. The right 

 pelvic fin bud appears during early caudal for- 

 mation (4.9 mm NL). Rays develop between mid- 

 flexion (6.0 mm NL) and late or postflexion (9-10 

 mm BL). Each complete fin has six rays. 



Rayless, fanlike, larval pectoral fins were 

 present on the smallest available specimen (pre- 

 flexion, 2.2 mm NL). Calcification of rays in the 

 left fin occurs between about 13 mm and 17.4 

 mm SL. Calcification of rays in the right fin had 

 not begun in the largest specimen (17.4 mm SL). 



Cephalic Spination 



Preopercular spines (Table 4) were present in 

 the smallest preflexion specimen (2.2 mm NL, 

 Fig. 4A). With development (Fig. 4B, C), addi- 

 tional spines appear until maximum numbers of 

 about 33 on the left (range 26-52) and 39 on the 

 right (range 23-50) are reached during late flex- 

 ion (6.4-8.9 mm NL). Thereafter, spines are lost 

 until none or only a few remain at transforma- 

 tion (17.4 mm SL, Fig. 5B). 



Frontal-sphenotic spines were evident in the 

 second smallest preflexion specimen (3.2 mm 

 NL) and throughout the larval series, though less 

 conspicuous near transformation (13-17 mm SL). 

 The lowermost spine on the left side is usually 



just above the center of the eye and on the right 

 side slightly anterior to the center of the eye. 

 (During transformation those on the right side 

 are at the anterior margin of the skull.) The 

 spines are arranged in a slightly posteriorly con- 

 cave arch following the curve of the skull. There 

 are usually six (up to eight) spines per side, in- 

 cluding three stronger spines arising from a 

 small bulge of the skull. 



Larval Teeth (Table 5) 



No teeth are present at 2.2 mm NL (Fig. 4A). 

 At 3.2-4.1 mm NL, larvae usually have two upper 

 and two lower teeth on each side. A 5.3 mm NL 

 preflexion specimen had three upper and four 

 lower teeth on each side. The same numbers were 

 present in the largest early caudal formation 

 specimen (5.7 mm NL). During flexion, numbers 

 of teeth increase from about four upper and five 

 lower (about 6 mm NL) to about eight upper and 

 seven lower (8.9 mm NL) on each side. Postflex- 

 ion larvae (10.4-13.8 mm SL) have about nine 

 upper and nine lower teeth on each side. The 

 nearly transformed specimen (17.4 mm SL, Fig. 

 5B) had fewer upper teeth on the left side (about 

 11) than on the right side (19) but the same num- 

 ber (about 15) in both lower jaws. 



Transformation 



Migration of the right eye may begin as early 

 as midflexion (6.4 mm NL) or as late as postflex- 

 ion (10.6 mm SL). The right eye moves from the 

 right side of the head through a space between 

 the dorsal fin and supraorbital bars (Fig. 5A) as 

 in Cyclopsetta fimbriata (Gutherz 1971). The 

 right eye reaches its final position on the left side 

 of the head by about 18 mm SL. No early juvenile 

 specimen was available, but eye migration in one 

 of the 17.4 mm specimens was nearly complete 

 (Fig. 5B). 



Occurrence 



Larvae were collected in the Atlantic during 

 February, March, April, May, October, and No- 

 vember (Powles 4 ). There was no apparent size 

 progression by month, indicating an extended 

 spawning season. Water depth was 46-640 m. 



4 H. W. Powles, Assistant Marine Scientist, South Carolina 

 Marine Resources Research Institute, P.O. Box 12559, Charles- 

 ton, SC 29412, pers. commun. July 1976. 



47 



