Fig. 58 — Capture localities for Myctophum mtidulum in the Pacific Ocean. 



Scopelus affinis ( = M. affine) was described by Liitken (1892), based on 38 collections from 

 the Atlantic and Indian Oceans. Carman (1899) described Myctophum nitiduliim from the 

 northeastern Pacific, type locality 27°50' N, 145°45' W. Gilbert (1905) described M. mar- 

 garitatum, based on material from the Hawaiian area and from about 28°13' N, 145°44' W (the 

 latter position is very near the type locality of M. mtidulum ). Gilbert (1908) synonymized both 

 these Pacific forms with M. affine. 



Gibbs (1957), reporting on material from the northwestern Atlantic Ocean and the Gulf of 

 Mexico, segregated two forms, each referrable to M. affine of Liitken. Gibbs characterized one 

 form as having ctenoid scales and a rounded dorsal portion of the opercular margin, and the 

 other form as having cycloid scales and a distinctly angulate posterodorsal margin of the 

 operculum. On the advice of Bolin, Gibbs applied the name M. affine to the form having 

 ctenoid scales and rounded opercular margin, and chose M. nitidulum as the earliest available 

 name for the cycloid-scaled form with the angulate posterodorsal margin of the operculum. 



Bolin (1959) reported that Liitken's original study material of M. affine, composed mostly 

 of juveniles, contained at least two species, one being M. asperum (Richardson), the other the 

 ctenoid-scaled, round-operculumed form reported by Gibbs (1957) as M. affine; Bolin desig- 

 nated a lectotype with the type locality in the Atlantic Ocean at 08° 44' N, 21° W for this latter 

 form. With some hesitation, Bolin accepted Gibbs' designation of the cycloid-scaled, angulate- 

 operculumed form as M. nitidulum. 



63 



