Diaphus gigas 



Gilbert, 1913 



Fig. 113 — Diaphus gigas, male, 44.9 mm. 



Description 



D. 16; A. 15; P. 12; AO 6 + 5, total 11; gill rakers 8 (7) + 1 + 16 (15-17), total 25 (23-26); 

 vertebrae 35. 



PLO below lateral line about one-third the distance between lateral line and pectoral 

 origin; VLO two or three diameters behind a vertical from pelvic origin and about midway 

 between lateral line and level of pelvic base. VLO low, two or more diameters below a line 

 through VLO-SAOj, SAO, its diameter above and behind VO-,; SAO2 about two diameters 

 above, and almost directly over SAO,; SAOa its diameter behind a line through SAO,.-, about 

 two diameters below lateral line and separated from SAO2 by a space about twice that between 

 SAO, 2- First AOa elevated to about its diameter below level of SAO^; last AOa elevated by 

 about two diameters above penultimate AOa, which is level with second, third, and fourth 

 AOa. Pol at least its diameter below lateral line and under anterior position of base of adipose 

 fin. Penultimate AOa-AOp, interspace about equal to that of AOp-Prc. 



Si^e: The largest of scant study material from the central Pacific Ocean was 57 mm. 

 Gilbert stated the holotype to be "172 mm. in total length, 140 mm. to base of caudal, — " and 

 the largest of two cotypes from Sagami Bay, Japan, as "21 cm." 



Least depth of capture: To 218 m at night. 



Distribution: In the eastern Pacific Ocean, known from only four localities (Fig. 108). Type 

 locality is Sagami Bay, Japan, 

 Discussion 



Diaphus gigas is very closely related to D. elucens in that the SAO.i and the Pol are close 

 to the lateral line, and the preorbital luminous organs are much alike. However, the name 

 gigas is applied here to the few specimens from the north-central Pacific (Fig. 108, solid 

 squares) because they agree well in certain body proportions with the description, and in 

 numbers of gill rakers (8 + 16) given by Gilbert. Body proportions for D. gigas, including those 

 given by Gilbert, are given in Table 19, and are compared with similar data for D. elucens from 

 the central Pacific and northern Atlantic Oceans. In general, D. gigas is more slender than D. 

 elucens and has a shorter and less deep head and a smaller eye. 



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