Lampanyctus tenuiformis (?) 



(Brauer, 1906) 



Fig. 168 — Lampanyctus tenuiformis (?), female, 110.0 mm. From the southeastern Pacific Ocean, 02°31' S, 137°04' W. 



Description 



D. 13-14; A. 17-18; P. 14 (13-15); AO 6-7 -I- 6-7, total 13 (12-14); gill rakers 4 (5) -(- 1 -I- 9 

 (10-11), total (see discussion); vertebrae 36 (37). 



PLO two to three of its diameters below lateral line; SAO.j, Pol, and Prcj touching lateral 

 line. VLO about over base of inner pelvic ray and slightly nearer lateral line than to pelvic 

 base. Line through PLO and VLO passes through or very near SAO,. Line through SAO3 and 

 SAO2 passes through or slightly behind VO4. 



Size: To 115 mm. 



Least depth of capture: To 300 m at night. 



Distribution: Apparently widespread in the eastern Pacific Ocean (Fig. 169) but, as few 

 specimens have been taken, it may be either uncommon or somehow unavailable to capture 

 gear. 

 Discussion 



Two possibly distinct forms of the provisional species are evident. Eight of the eleven 

 specimens showed little variation in numbers of gill rakers, all having 4+1 + 9, except one 

 which had 5 + 1 + 9 on the right side. Also, in these specimens the Prc-j.^ interspace was 

 notably greater than that between Prciand Prc:). Three of the eleven specimens (in three 

 collections from the northeastei'n Pacific, enclosed by dashed line in Fig. 169) differed in that 

 the Pre.!., interspace was equal to or slightly les than that of Prci.j. The number of gill 

 rakers was also higher, 5 + 1 + 10-11; one specimen (of two), totally denuded, had 4+1 + 9 

 rakers, whereas the other (all photophores present) had 5 + 1+10; the respective sizes were 38 

 and 48 mm. 



Based on criteria given in Table 35 and in the foregoing key, specimens conforming 

 strictly to either L. tenuiformis or L. festivus were not found in the eastern Pacific Ocean; 

 however, 11 specimens (9 collections) in good condition, from widely scattered areas of the 

 Pacific (Fig. 169), have characters that are presumed to differentiate L. tenuiformis and L. 

 festivus (Table 35). It may be that these Pacific specimens represent a new species, but because 

 of the paucity of information on either L. tenuiformis or L. festivus they may also merely 

 reflect an unknown variation in these species. Therefore, until further study the older name, 

 tenuiformis, is provisionally applied to the Pacific forms. 



However, as the western and southern areas of the eastern Pacific Ocean are inadequately 

 collected it is possible that the forms from the Indian Ocean, identified as L. tenuiformis and L. 

 festivus by Nafpaktitis and Nafpaktitis (1969, p. 48, figs. 57, 58) may eventually be found in 

 these marginal areas. Therefore, the figures provided by these authors for the two species are 

 reproduced here (Figs. 170 and 171). 



183 



