MARLIAVE and PEDEN: LARVAE OF LIPARIS FUCENSIS AND L. CALLYODON 



forming anteriorly, extending in decreasing 

 length posteriorly. Pectoral rays were not evi- 

 dent in unstained material. Although the pec- 

 torals were very fully pigmented at this stage, 

 the melanophores did not align with the underly- 

 ing rays. 



At the beginning of flexion, larvae between 

 6.7 and 7.3 mm NL developed dorsal, anal, and 

 pectoral fin rays synchronously, prior to forma- 

 tion of caudal rays (Fig. 2c). Nape, gut, mandi- 

 bular, and pectoral melanophores remained very 

 prominent, with the addition of a few large 

 melanophores in the opercular area. By this 

 stage, the bubble was large and rather spherical, 

 thus allowing epidermal melanophores to be dis- 

 tinguished readily from gut melanophores. The 

 dorsal bubble melanophores around the nape 

 were large and usually separated by a gap in 

 epidermal pigment laterally, located in the plane 

 of the large dorsal gut melanophores. The ven- 

 tral bubble melanophores were markedly 

 smaller by this stage, as were the mandibular 

 melanophores. During flexion, postanal ventral, 

 midhne melanophores, particularly those in pos- 

 terior positions, began migi-ating dorsally along 

 the myosepta. Ventral fin fold melanophores 

 eventually became aligned with the tips of anal 

 fin rays. 



During flexion, the final orientation of nares 

 was attained, with the ventral naris on each 

 side oriented anteriorly, and the dorsal naris, 

 dorsally, and with the separation distance be- 

 tween the two nares of each pair similar to that 

 of later stages, i.e., about 0.5 of eye diameter, 

 slightly less than during preflexion. The pelvic 

 disk was well developed and circular at this 

 stage, slightly less than half of eye diameter in 

 size. The pectoral fin did not extend ventrally to 

 the pelvic disk, and no exserted lower rays 

 were present. 



During early postflexion, larvae up to 10 mm 

 SL developed lower exserted pectoral rays but 

 only in individuals in which caudal ray formation 

 was completed (Fig. 2d). Early during post- 

 flexion, very small, mandibular, acousticolater- 

 aHs pores became evident, three on each side. 

 The pelvic disk was still small, embedded within 

 an invagination of the bubble. The tail region 

 formed a subdermal swelling, starting ante- 

 riorly, at sizes between 9 and 10 mm SL, extend- 

 ing out to under half the length of median fin 

 rays. 



Postflexion larvae tended to lose melano- 

 phores characteristic at earlier stages, while 

 simultaneously developing new melanophores in 



other positions. Greater pigment variability be- 

 tween individuals was more evident at this stage 

 than in earUer stages. All postflexion larvae lost 

 the melanophores on the outer half of the pec- 

 toral fins, retaining rows of melanophores lining 

 pectoral rays toward the fin base. A few individ- 

 uals retained very small melanophores lining the 

 fringe of the pectorals. These melanophores 

 were frequently just on the dorsal tip of the 

 pectoral fins, which tended to become less 

 pointed via allometric reduction in ray length 

 when the lower exserted rays formed. The 

 exserted pectoral rays never developed pigmen- 

 tation in larvae. Many individuals lost the small 

 melanophores on the ventral bubble and man- 

 dibles, while the internal melanophores on the 

 gut surface became obscured by the increasing 

 thickness of the granular epidermis (cf. Fig. 1). 

 Melanophores tended to develop along the mar- 

 gin of the tail swelHng of the subdermal space, 

 aligned with the midpoints of the dorsal and anal 

 fin rays. At 16.8 mm SL (17.4 mm SL fresh. Fig. 

 2e), the outer skin was sparsely overlaid with 

 melanophores everywhere except in the anterior 

 cranial area. The melanin was most dense over 

 the preopercular region and between the eye and 

 the maxillary. 



The largest postflexion larva, prior to the 

 metamorphic allometry that yielded the juvenile 

 morph, had tubular dorsal nares like the 

 juveniles, but embedded in the bubble. The 

 exserted, ventral, pectoral rays were the same 

 length as the longest pectoral rays dorsally. The 

 anterior portion of the dorsal fin was no longer 

 visible within the bubble. Thus, only 25 posterior 

 dorsal rays and 23 anal rays were evident. The 

 mandibular, acoustico-lateralis pores were 

 prominent and were aligned in a series of four on 

 each side, extending toward the preoperculum. 

 Two smaller pores were over the maxillary on 

 each side. The pelvic disk had developed muscu- 

 lar papillae inside the margin; the shape was a 

 flattened oval, with a width equal to the eye 

 diameter. 



The two larvae that survived to the juvenile 

 stage in captivity underwent a metamorphic loss 

 of the subdermal bubble. Over a period of nearly 

 a month in the laboratory, the larvae were ob- 

 served to show ambivalence between settlement 

 and swimming in the water column. The pelvic 

 disk was functional. Abruptly, the bubble ap- 

 pearance was lost on one juvenile that was ob- 

 served at that stage; shrinkage occurred, giving 

 the juvenile a slender, distinctively liparidine 

 appearance. The other juvenile could not be 



739 



