Watson; Early life history stages of Cheilopogon xenopterus 



1037 



Cheilopogon xcii 

 (B) juvenile. 36, 

 shown in dotted 



about 38 mm. Pelvic-fin buds 

 form during embryonic stage IX, 

 at about completion of notochord 

 flexion. All six pelvic-fm rays ap- 

 parently present at hatching. 



Cartilaginous dorsal- and anal- 

 fin pterygiophores form late dur- 

 ing embryonic development: 

 cleared and stained late stage-X 

 embryo had six dorsal, five anal- 

 fin pterygiophores. Addition and 

 ossification of pterygiophores ap- 

 parently anterior to posterior. 

 Each pterygiophore initially is 

 single cartilage which begins to 

 ossify near middle of lower por- 

 tion (forming proximal radial). 

 Although pterygiophores did not 

 stain well in smaller larvae, at 

 least first three or four anal-fin 

 pterygiophores beginning to os- 

 sify in 3.8-mm specimen and first 

 five or six dorsal- and anal-fin 

 pterygiophores in 5.2-mm speci- 

 men. By 6.3 mm all but posterior 

 three or four dorsal proximal ra- 

 dials ossifying, and distal radials 

 appear to be ossifying adjacent to 

 fin-ray bases. About 8.2-13.4 mm 

 separate ossifications, probably 

 representing middle radials, form on cartilage be- 

 tween proximal and distal radials, but by 16.8 mm 

 each proximal -i- middle radial appears to be a single 

 ossified unit. Dorsal- and anal-fin rays begin to form 

 in stage-Xl embryos; all anal- and most dorsal-fin 

 rays present at hatching. 



Pigmentation 



Most elements of basic pattern established during 

 late embryonic development are visible throughout 

 larval period. Principal internal elements of pattern 

 are 1) melanophores under mid- and hindbrain (dif- 

 ficult to see after about 6 mm); 2) row over notochord 

 (difficult to see after about 6 mm); 3) melanophores 

 present around urostyle and proximally on hypurals; 

 4) melanophores present dorsally, dorsolaterally on 

 gut. Principal external elements are: 1) dorsal mel- 

 anophores covering mid- and hindbrain areas; 2) two 

 somewhat irregular rows along dorsal margin of 

 trunk and tail (increasing to four rows after about 9 

 mm), and melanophores in each row usually more 

 ^closely spaced along posterior half of dorsal-fin base; 

 3) two rows along anal-fin base, commonly expanded 

 along posterior half of fin base; 4) patch on each side 



Figure 3 



optenis. lateral view. (A) lan-a. 12. .5 mm (8910M4, station l-OlOl; 

 4 mm (8910JD. station 1-039). Fin rays (and fin pigment in Al 

 lines are based on fins of other specimens of similar size. 



over urostyle and hypural area; 5) scattered melano- 

 phores on pectoral, pelvic, and caudal fins. 



Subsequent additions to internal pigmentation 

 include melanophores spreading around sides of mid- 

 and hindbrain and increasing in number anteriorly 

 over notochord, forming internally on opercular area 

 beginning at about 6-6.5 mm, and spreading vent- 

 rolaterally on gut (primarily anteriorly), surround- 

 ing gut at level of pectoral-fin bases between 12 and 

 18 mm. Pigmentation on urostyle and hypural area 

 usually increases somewhat. External dorsal pigmen- 

 tation on head slowly increases, spreading forward 

 onto snout after about 13 mm. Melanophores form 

 on upper jaw by about 10 mm. In early juveniles, 

 melanophores over mid- and hindbrain spread 

 ventolaterally, reaching level of pectoral-fin origin 

 by about 36 mm. External melanophores present on 

 central opercular area by about 8 mm (Fig. 2C), form 

 indistinct bar across cheek by about 12-15 mm (Fig. 

 3A). Barbels initially unpigmented, become densely 

 pigmented distally, usually beginning between 6 and 

 7 mm. As barbels broaden, melanophores become 

 more concentrated along distal margins and after 

 barbel fusion, connecting membrane becomes in- 

 tensely pigmented along distal margin (by 12-13 mm: 



