MATSUURA and YONEDA: EARLY DEVELOPMENT OF LOPHIID ANGLERFISH 



Table 1 .—Statistics describing regressions relating notochord length with length of different body 

 parts of Lophius gastrophysus larvae, a and b = constant (y = a + bx), r = correlation coeffi- 

 cient, n = number of specimens. 



lines of the former were calculated in two size 

 ranges. 



PIGMENTATION 



Lophius gastrophysus larvae develop a distinct 

 pattern of melanophores. Since early stage (Fig. 

 1 A), there are three large pigment bars on the trunk 

 and caudal region and they remain at the same posi- 

 tion during larval stage. The larva of 14.9 mm NL 

 (Fig. IF) has a heavily pigmented body, but the three 

 large pigment bars on the trunk and caudal region 

 are still visible. There are dense melanophores over 

 the occipital region of the head and shoulder (Fig. 

 1A). Pigments on the elongate ventral fin ray is also 

 visible in the smallest specimen, but the positions 

 and number of them change gradually. In the 

 earliest stage (3.8 mm NL) there are two melano- 

 phores on the ventral fin: one at the fin ray base 

 and another at the middle of the ventral fin. At the 

 size of 4.5 mm NL (Fig. IB), there appears another 

 small melanophore at one-third the length of the fin 

 ray. The melanophore at the fin ray base remains 

 at the same position, but the distal large one moves 

 to the position three-fourths the length of the fin 

 ray. After this size, positions and number of melan- 

 ophores on the elongate third ventral fin ray remain 

 the same up to 15.7 mm NL. When distal part of 

 other ventral fin rays start to separate from the 

 third one, there appears some melanophores on the 

 distal edge of each fin ray. 



There appears a patch of melanophores on the 

 preopercular region at 3.8 mm NL and another small 

 one appears on the suborbital region at 4.5 mm NL. 

 The small melanophore, which appears on the tip 

 of the elongate second dorsal spine at 4.5 mm NL, 

 will later become a large pigment bar (Fig. 1C, 

 D). 



FIN DEVELOPMENT 



The most remarkable change can be seen in 

 lengths of the dorsal and ventral fins. Since the 

 earliest stage (Fig. 1A), the larvae have elongate 

 dorsal spine and ventral fin ray, which later become 

 the second dorsal spine and the third ventral fin ray, 

 respectively. The length of the second dorsal spine 

 relative to body length changed from 28% at 3.3 mm 

 NL to 90% at 8.3 mm NL (Fig. 2A). In larger lar- 

 vae the proportion of the second dorsal spine length 

 relative to body length decreased gradually to 70% 

 at 15.7 mm NL. A similar tendency was observed 

 for the length of the third ventral fin ray: it varied 

 from 45% of body length at 3.3 mm NL to 121% at 

 11.6 mm NL (Fig. 2B). Unfortunately, these fin rays 

 are in many cases lost or damaged at the distal tip, 

 making it difficult to say whether we measured the 

 total length of fin rays or the partial length of a 

 damaged ray. In any case, the figure shows a clear 

 tendency of rapid increase of fin rays during larval 

 stage. 



The number of fin rays increases during larval 

 stage. For example, the origin of the first dorsal 

 spine firstly appears anterior to the elongate sec- 

 ond dorsal spine in 9.2 mm NL larva (Fig. IE). The 

 tip of the first dorsal spine which will transform in- 

 to the illicium in the adult fish, emerges from the 

 epidermal skin at about 10 mm NL. At this size, all 

 fin rays are well developed and number of fin rays 

 on the second dorsal, anal, and caudal fins attains 

 the adult number. 



Another remarkable change in fin development 

 is a forward advancement of the dorsal spines. At 

 3.3 mm NL larva, the elongate second dorsal spine 

 lies behind the head (Fig. 1A) and it moves gradu- 

 ally forward during larval stage; at 14.9 mm NL, 



433 



