Fig. 195 — Ceratoscopelus warmingii. female, 58.0 mm. From Nafpaktitis and Nafpak- 



titis(1969, p. 64, fig. 76). 



Nafpaktitis and Nafpaktitis (1969) (Fig. 195). Craddock and Mead ( 1970) reported capture of 

 163 specimens (21-93 mm) from west of Valparaiso, Chile, in the areaof about 3r-33° S, 

 77°-92°W( 16 collections). 



As noted for other myctophid fishes, individuals o{ Ceratoscopelus appear to avoid, or are 

 rarely taken, in the eastern tropical Pacific over much of the area of oxygen-deficient water 

 (Fig. 194). 

 Discussion 



C. warmingii described from the North Atlantic Ocean, has been regarded by most au- 

 thors as a synonym of C townsendi , described from Cortez Bank, near San Diego, California, 

 in the northeastern Pacific Ocean. Nafpaktitis and Nafpaktitis (1969) reported the capture of 

 many specimens of the genus Ceratoscopelus from the western Indian Ocean, and stated that 

 these specimens were generally very similar to specimens of C. warmingii from the North 

 Atlantic and that a direct comparison of the two forms with C. townsendi from the northeast- 

 ern Pacific Ocean revealed the principal differences stated in the above key to species. They 

 further stated, "Prior to the development of the supraorbital gland (individuals smaller than 

 about 27 mm), or in cases of poorly preserved specimens (supraorbital glands rubbed off), it is 

 difficult to distinguish C. townsendi from C. warmingii. Minor differences which, considered 

 together, may help distinguish the young and poorly preserved adults of the two species 

 include: series of luminous scales along the bases of the caudal procurrent rays often extending 

 to vertical through Prc4 in C. warmingii (the character does not apply to populations from 

 equatorial Atlantic waters), not reaching vertical through Prca in C. townsendi; pectoral fin 

 extending to the fourth AOa in C. warmingii, not reaching the second AOa in C. townsendi; 

 absence of luminous tissue between PVOi and PVO2, anterodorsad to PO3 and PO4, above the 

 base of ventral fin and over the origin of the anal fin in C. townsendi." 



On the basis of the presence or absence of the supraorbital tissue these authors concluded 

 that C. townsendi was limited to the northeastern Pacific (Fig. 194), and that C. warmingii 

 was widely distributed in the Atlantic, Indian, and probably South Pacific Oceans. In regard to 

 this sole criterion, it would seem that these authors were correct. I have found specimens 

 having supraorbital luminous patches only among those captured at localities east of the 

 heavy line shown in Fig. 194, draw roughly parallel to the coast of North America. No sup- 

 raorbital luminous tissue was found on any specimen from elsewhere in the Pacific Ocean; 

 many were in such excellent condition that it could only be concluded that such tissue was 

 never present. 



However, the other critera offered by Nafpaktitis and Nafpaktitis ( 1969) for separating 

 the two species appear to be of questionable value. In the northernmost portion of the area of 

 C. townsendi, off North America (Fig. 194), I found some specimens bearing supraorbital 

 luminous tissue to have pectoral fins reaching to or beyond AOaa, and luminous scales reach- 

 ing to under or beyond Prc;,. Also, an occasional specimen had luminous scales in the areas of 



208 



