the adult complement is 3 + 2 hypurals. The stained lar- 

 vae had 8 + 7 principal rays and 6 + 6-7 procurrent rays. 

 All stained larvae had 24 vertebrae. Gill rakers ranged 

 from 5 to 6 on the upper limb and 8 to 12 on the lower 

 limb of the first arch. There were 7 branchiostegal rays. 



Early larvae of Pontinus Type A are sparsely pig- 

 mented. The initial melanophore pattern is similar to 

 that of Scorpaenodes. A series of 11 to 16 melanophores 

 (mean of 13 ± 1.3 SD for 14 larvae counted) is present 

 along the ventral midline of the tail. The series extends 

 from the anus posteriad to the hypural anlage of the 

 caudal fin. A wider space separates the ultimate 

 melanophore from the others. The number of 

 melanophores and their spacing is similar in Scor- 

 paenodes xyris except that in that species the series ex- 

 tends farther anteriad to the point of divergence of the 

 terminal section of the gut. In Pontinus Type A larvae 

 the ventral tail melanophores begin to become em- 

 bedded during notochord flexion and are not visible in 

 larvae larger than 6.0 mm. 



Other pigment present initially is a medial blotch 

 anterodorsad to the axillary region. With further 

 development this expands to form a shield over the gas 

 bladder. It becomes progressively less visible with 

 thickening of the trunk musculature. Similar pigment is 

 present in Scorpaenodes and Ectreposebastes. 



Pigment is present initially on the gut as a few faint 

 melanophores along the dorsal surface of the preter- 

 minal section of the gut and as a streak along the ventral 

 midline, with heaviest concentration below the liver. 

 Also, fine melanophores are present along the edge of the 

 finfold just anterior and posterior to the anus. These 

 areas of pigmentation persist in larvae up to about 5.5 

 mm in length and are present thereafter. When the lar- 

 vae reach about 10.0 mm in length, large melanophores 

 begin to appear internally on the perivisceral membrane 

 and, with further development, eventually cover the 

 entire membrane. 



The other pigmentation present initially is on the pec- 

 toral fins. Minute melanophores cover the entire blade of 

 the fin and are present at the margin of the medial sur- 

 face of the fin base. This contrasts with the pattern in 

 early larvae of Scorpaenodes which have, at most, the 

 distal half of the fin blade covered with melanophores 

 and which have none on the fin base. The pattern of pig- 

 mentation on the pectorals of Pontinus Type A goes 

 through a series of distinct changes as larval develop- 

 ment proceeds. Towards the end of notochord flexion the 

 melanophores disappear from the fin base and begin to 

 recede from the basal region of the fin blade. The basal 

 clear area continues to enlarge and, at maximum reces- 

 sion in larvae of about 10 mm in length, pigment is 

 reduced to the distal margin. At about 10.0 mm the dis- 

 tal band begins to expand and becomes progressively 

 wider during the remainder of the larval period and 

 pelagic juvenile phase. At the end of the pelagic juvenile 

 stage only a small portion of the fin remains unpig- 

 mented. Newly transformed benthic juveniles have a 

 mottled pattern on the fins with a prominent dark blotch 

 near the base. 



In larvae about 6.5 mm long, a melanistic blotch ap- 

 pears on the membrane between the 3rd and 4th spinous 

 rays of the dorsal fin. Additional blotches appear an- 

 terior and posterior to this as development proceeds, and 

 larvae larger than 7.0 mm have a series of blotches from 

 the 2nd and 3rd interradial membrane to the 5th or 6th 

 membrane. In pelagic juveniles the entire membrane of 

 the spinous dorsal fin becomes pigmented; however, a 

 much darker blotch is present between the 6th and 11th 

 spines. This dark blotch persists in benthic juveniles. 



Melanophores appear on the brain in 10-mm larvae, 

 initially with a single pigment spot above each optic 

 lobe. Others form rapidly and the entire dorsal surface of 

 the brain is covered in larvae larger than 13.0 mm. 



Saddles of melanistic pigment begin to form on each 

 side of the dorsal midline in 13-mm larvae, one between 

 the 1st and 2nd dorsal spines, and the other between the 

 5th and 7th spines. These enlarge to include the regions 

 between the 1st and 3rd dorsal spines and the 5th and 

 10th spines in larvae larger than 15.0 mm. Two other pig- 

 ment saddles appear in pelagic juveniles, one below the 

 soft dorsal fin and the other at the caudal peduncle. In 

 the largest pelagic juveniles, the anterior pigment sad- 

 dle covers the nape, the large one posterior to it bifur- 

 cates and extends ventrad to the horizontal septum, the 

 one below the soft dorsal extends ventrad to the base of 

 the anal fin, and the one at the peduncle is a weak band. 

 These markings break up into a more complex pattern in 

 benthic juveniles. 



Pigmentation appears on other regions in pelagic 

 juveniles. At about 15.0-mm length, a blotch forms at the 

 midregion of each pelvic fin and the entire membrane of 

 the fin is pigmented at about 20.0-mm length. When 

 pelagic juveniles reach about 25-mm length, a blotch ap- 

 pears at the midregion of the soft dorsal and the soft anal 

 fin. These appear as extensions of the prominent trunk 

 band in benthic juveniles. 



The head becomes pigmented in pelagic juveniles first 

 on the opercle and on the region above the opercle. At the 

 end of the pelagic phase, the entire lateral aspect of the 

 head is mottled. 



Distribution. — The midwater trawl and plankton col- 

 lections of CalCOFI, EASTROPAC, and the STOR 

 group show the geographic distribution of larvae and 

 pelagic juveniles of Pontinus Type A (Fig. 36). CalCOFI 

 plankton collections show that larvae and pelagic 

 juveniles of Pontinus Type A occur in the Gulf of Califor- 

 nia up to about lat. 28°N. On the outer coast of Baja 

 California, pelagic juveniles of Pontinus Type A have 

 been taken as far north as Punta Eugenia (about lat. 

 28°N). Collections of the EASTROPAC expedition and 

 STOR show that larvae and pelagic juveniles occur 

 southward to the northern coast of Peru (about lat. 5°S). 

 It has an extensive distribution in the Gulf of Panama 

 and westward to the Galapagos Islands. In general, its 

 distributional pattern is similar to that of Scorpaenodes 

 xyris except that Pontinus Type A is more abundant in 

 offshore regions along the tropical American coast. Lar- 

 vae occurred in small numbers in both CalCOFI and 



63 



