172 



ONTOGEIVY AND SYSTEMATICS OF FISHES -AHLSTROM SYMPOSIUM 



Table 45. Photophore Counts of Stomiatoid Genera. Most frequent count or range is followed by overall range or infrequent count in 

 parentheses. Data sources as in Table 1. Photophore groups as defined by Morrow (1964a). 



vertebral counts that match Macrostomias longibarbatus. Its 

 morphology is that of a highly attenuate Stomias larva. Pig- 

 mentation is restiicted to a series of small melanophores along 

 the ventral midline of the gut. The ventral photophore rows are 

 beginning to form. 



Chauliodontidae (Fig. 59). — Larvae of five species are known 

 (Table 46). Larvae are 6-7 mm long at hatching, with an elongate 

 yolk sac. The body is slender with a circular cross-section, and 

 remains so throughout development. The head is relatively small, 

 with elliptical eyes and a short, acute snout. The gut has a smaller 

 diameter than in Stomias but is relatively longer. The short 

 terminal section extends beyond the anal fin origin. The median 

 finfold is small and best developed rearward on the body. The 

 dorsal, anal, and pelvic fins form in late postflexion larvae in 

 the adult position. A fan-shaped array of melanophores occurs 

 in the caudal region of yolk-sac larvae but is soon lost. No other 

 pigment develops. Larvae of some species reach 46 mm SL and 

 there appears to be marked shrinkage at transformation. 



Astronesthidae (Fig. 90). — Astronesthid larvae have been illus- 

 trated and described briefly by Roule and Angel ( 1930), Whitley 

 (1941), Pertseva-Ostroumova and Rass (1973), and Belyanina 

 (1982b); however only two of these were identified to genus 

 (Table 46). We have examined more than 10 types of astro- 

 nesthid larvae, 7 of which are listed in Table 46. Astronesthid 

 larvae display a great variety of structure and pigmentation, but 

 hold in common the advanced position of the dorsal fin, in 

 contrast to other Stomiatoidea, except Chauliodus. The types 

 differ fundamentally in gut shape and body form: Types I and 

 II are laterally compressed, relatively deep-bodied, and have a 

 non-trailing or slightly trailing gut with terminal section as in 

 melanostomialids; Types III-VIl have a slender body and a 

 trailing gut; in Types III-V the gut is deflected ventrad from 

 the body just anterior to the anal fin base and in Type VI and 

 VII at midbody, anterior to the dorsal fin (Figure 90). 



Type I (Fig. 90A). — larvae up to 26.5 mm; laterally compressed; 

 head shallow with acute snout; eyes relatively large, slightly 



Fig. 90. Larvae of Astronesthidae. (A) Type I, 23.7 mm, ORl A105; (B) Type II. SIO Tasaday I A3; (C) Type IV. 33.0 mm. MCZ Cat. No. 

 59855; (D) Type V, 22.0 mm, Dana Sta. 3931; (E) Type VII, 28 mm, MCZ Cat. No. 59856. 



