PLO below lateral line by one-third to one-fourth the distance from there to pectoral 

 origin. PVO,., interspace about half that of PLO-VPO,.. PLO and PVO, ^ form straight, 

 posteriorly slanting line that passes slightly before POo. PO4 elevated to about level of middle 

 of pectoral base, or somewhat lower, and to its diameter behind a vertical from PO:). VLO about 

 midway between lateral line and pelvic base and about over middle of that base. SAOi below 

 level of SAO2 and about over midpoint of VOj.n interspace, often slightly nearer to VO.j. 

 SAO1.2 interspace about one and one-half times that of SAO2.3. A line through SAOm; passes 

 through or below PO4; a line through SAO^ .) passes slightly behind VO4. SAO^ about over 

 anus; SAO,, slightly behind vertical from AOa, and over bases of third or fourth anal rays. A 

 line through the 2 Pol passes slightly behind last AOa. AOa-AOp interspace slightly less than 

 half least depth of caudal peduncle and about equal to that between Pre,..!. AOp continuous 

 with Pre. First 3 Pre equally spaced in curve; Prc4 at or above lateral line and separate from 

 Prc3 by a space about a third greater than that between Pre, and Pre,;. 



Stze.TollOmm. 



Least depth of capture: To 200 m at night off South Africa. 



Distribution: L. lepidolychnus appears to occur circumglobally in southern waters, proba- 

 bly below 30° S. It is known from off South Africa and Argentina and from south-central Pacific 

 and Indian Oceans. It has not yet been reported from the southeastern Pacific, off Chile, where 

 the related species, L. intricarius, is moderately abundant. 

 Discussion 



Lampanyctus lepidolychnus and L. intricarius are very similar. They may be confused 

 primarily because of the similarity in positions of the depressed AOaa photophores. However, 

 in addition to those characters given above, and the few differences in body proportions (Table 

 38), the two species differ somewhat in the percentage values of depth to length of the caudal 

 peduncle: 49% (45-57% ) for L. lepidolychnus, vs 43% (36-48% ) for L. intricarius. Also, the color 

 (in preservative) of the latter species is a light to medium brown, whereas the former is very 

 dark. 



Other characters useful in distinguishing between L. lepidolychnus and L. intricarius are 

 given in Table 39. 



Table 39. Some Characters Useful in Distinguishing Between Lampanyctus 

 lepidolychnus and l. intricarius. 



L. lepidolychnus 



L. intricarius 



SAOi below level of SAO2 

 AOa-AOp interspace slightly less 



than half least depth of caudal 



peduncle and about equal to that 



of Pre,., 

 Pre .I.J interspace slightly less 



than that of Pre,.;, 

 Least depth of caudal peduncle 49% 



(45-57% ) of length of peduncle 

 Color in preservative very dark 



SAOi on or above level of SAO2 

 AOa-AOp interspace about as in 



L. lepidolychnus but much greater 



than that of Prc.,.j 



Prcj., interspace about one-third 

 greater than that of Pre,.., 



Least depth of caudal peduncle 



43% (36-48%) of length of peduncle 



Color in preservative light to 

 medium brown. 



L. lepidolychnus is also somewhat similar to L. iselinoides but differs in part in that the 

 pectoral fin of the latter is much shorter (scarcely reaching to pelvic origin), and the length of 

 the pectoral base averages 28% (24-31%) of the length of the orbit. The percentage values for 

 depth to length of caudal peduncle are higher in L. iselinoides — 43% (40-46% ). Also, this latter 

 species has 2 cheek photophores, rather than 1, and the last 3 Pre are in a straight, oblique 

 line, rather than in a curve as in L. intricarius . 



197 



