Table 20. Correlated Counts (Both Sides) of AO Photophores and Gill Rakers for 

 diaphus rolfbolini 



AOp 



Lower rakers (including central raker) 



Preorbital area of holotype and several paratypes covered with a viscous, transparent 

 substance that creates a domelike effect. Entire posterior surface of the preorbital area ap- 

 pears to have a highly reflective lining and no doubt glows when the luminous organs are 

 active. There is no appreciable sexual dimorphism in these organs. 



Size: To about 54 mm. 



Least depth of capture: Between 50 and 200 m at night and 600 m in daytime (Clarke, 

 1973). 



Distribution: Thus far known from the warmer waters of the central Pacific (Fig. 108) 

 between about 14° S, 93° W and 17° N, 154° W and in the western Pacific and Indo-Pacific 

 areas. 



Discussion 



Diaphus rolfbolini is closely related to D. effulgens (Goode and Bean, 1896). It differs 

 primarily in having a total of 25-26 (24-27) gill rakers, rather than 20-21 (19-22). Also, it may 

 be a smaller species, as the largest of 87 specimens available was 65 mm. A gravid female of 60 

 mm was found. Nafpaktitis ( 1968) reported that no gravid females were found among his study 

 material of D. effulgens from the North Atlantic Ocean, and that "At best, female specimens of 

 about 130 mm and males of 85 to 105 mm showed medium-sized, finely granular, flaccid 

 ovaries and large, healthy looking testes, respectively. The species reaches a relatively large 

 size (commonly 120 to 130 mm)." 



Diaphus ostenfeldi 



Tuning, 1932 



Fig. 116 — Diaphus ostenfeldi, male, 99.3 mm. 



123 



