Diaphus richardsoni 



Taning, 1932 



Fig. 128 — Diaphus richardsoni, male, 50.0 mm. From the Java Trench. 



Description 



The following data are taken from four specimens, one each from Java Trench, South 

 China Sea, Sulu Sea, and off Durban, South Africa. 



D, 12-13; A. 13; P. 10 (11); AO 5 + 3-4, total 8-9; gill rakers 6 + 1 + 13-14, total 20-21; 

 vertebrae 32. 



PLO above pectoral origin by about one-third the distance from there to lateral line. VO4 

 elevated to about level of pectoral origin. VLO slightly behind pelvic origin and nearer to it by 

 about one-third the distance to lateral line. VLO about half its diameter above level of VO.,, a 

 line through these 2 organs passing well above PLO. SAO series very slightly angulate; a line 

 through SAO1.2 passes a little before VO,-, and behind SAO.^. First AOs not elevated; ultimate 

 AOa elevated by about its diameter above penultimate AOa. SAOj and Pol below lateral line 

 by two to three times their diameters. 



Diaphus richardsoni is closely related to D. brachycephalus . It differs primarily in having 

 no heavily pigmented area around the So, and the Vn of males is much less massive anteriorly 

 than in D. brachycephalus; the Vn of females is similar in the two species. Also, D. richardsoni 

 appears to have the external pore structure of the lateral line less strongly developed. It has a 

 more slender body, as indicated in the body proportions in Table 25. 



Size: To 57 mm (Holotype). 



Least depth of capture: To about 200 m at night. 



Distribution: This species has not yet been reported from the eastern Pacific Ocean, but 

 since the type locality is north of new Guinea (02° 00' N, 138° 22' E), it may occur in the poorly 

 collected southwestern section. 



Diaphus anderseni 



Tanmg, 1932 



Description 



D. 13; A. 11-12; P. 10-11 (9); AO 4 (3-5) + 5, total 9 (8-10); gill rakers 5-6 (4) + H- 12 

 (11-13), total 18-20; vertebrae 33 (32-34). 



Body photophores large, those of SAO and AO series less than half a diameter apart. PLO 

 before pectoral origin and somewhat nearer it than to lateral line; VLO only two or three of its 

 diameters above pelvic base. Pre closely spaced, in a moderately flat curve. 



143 



