SYSTEMATICS AND DISTRIBUTION OF CERATIOID ANGLERFISHES 



OF THE FAMILY MELANOCETIDAE WITH THE DESCRIPTION OF 



A NEW SPECIES FROM THE EASTERN NORTH PACIFIC OCEAN* 



Theodore W. Pietsch and John P. Van Duzer^ 



ABSTRACT 



The ceratioid anglerfish family Melanocetidae is revised on the basis of a study of approximately 600 

 specimens collected from all oceans. Of the 11 nominal species of Melanocetus based on females, 4 are 

 recognized: M.johnsoni, with M. krechi, M. rotundatus, M. ferox, M. cirrifer, and M. megalodontis as 

 synonyms; M. polyactis; M. niger; and M. murrayi , with M. vorax and M. tumidus as synonyms. A fifth 

 species is newly described from a single female collected from the eastern Pacific Ocean off Mazatlan, 

 Sinaloa, Mexico. The new form differs most strikingly from its allies in having a larger escal bulb and 

 shorter jaw teeth. 



Melanocetus is widely distributed throughout all the major oceans of the world between about 250 m 

 and some unknown lower depth limit that exceeds 3,000 m. Melanocetus johnsoni and M. murrayi are 

 wide ranging forms, whereas M. polyactis and M. niger are apparently restricted to the eastern tropical 

 Pacific. 



Melanocetus murrayi appears to be the most phylogenetically derived member of the family. The four 

 remaining species are much more closely related to each other than any is to M. murrayi. Melanocetus 

 johnsoni is perhaps derived in having a relatively long illicium, and in having fewer, but longer jaw 

 teeth. Melanocetus polyactis and M. niger are similar in having relatively short jaw teeth, a similar 

 escal morphology, and a sympatric geographic distribution that is limited to the eastern tropical 

 Pacific. The newly described form is derived in having an extremely large escal bulb, comparable with 

 no other known ceratioid. 



The Melanocetidae include globose, bathypelagic 

 anglerfishes, easily separated from members of 

 allied families by having 12 or more dorsal fin rays, 

 3 or 4 anal rays, and large, fanglike jaw teeth 

 (Bertelsen 1951; Pietsch 1972a). The only recog- 

 nized genus of the family was established by 

 Giinther (1864) with the description of Mel- 

 anocetus johnsoni, based on a single female 

 specimen collected in the Atlantic Ocean, off 

 Madeira. Since that time, 10 additional species 

 based on females have been described (Table 1). 

 From a comparison of the characters used to dis- 

 tinguish these nominal forms, Bertelsen (1951, 

 table 4) doubted that M. krechi and M. cirrifer 

 could be maintained and that M. ferox and M. 

 niger might be synonyms. Melanocetus murrayi 

 and M. johnsoni were recognized as the only 

 species known from the Atlantic; M. niger, M. 

 ferox, and M. polyactis were considered forms re- 

 stricted to the eastern tropical Pacific. Six larval 



'Contribution No. 516 from the College of Fisheries, Univer- 

 sity of Washington, Seattle, WA 98195. 



J'College of Fisheries, University of Washington, Seattle, WA 

 joiyo. 



Manuscri 



rio'Ji'4'^"P' accepted September 1979. 

 nSHERV BULLETIN: Vol. 78, NO. 1, 



1980. 



specimens from the Gulf of Panama were assigned 

 to M. polyactis. The remaining larvae (approxi- 

 mately 600 individuals) were separated into two 

 groups, representing M. murrayi and M.johnsoni, 

 on the basis of geographic distribution, fin ray 

 counts, and a comparison of larval and adolescent 

 female pigmentation. Despite these allocations, 

 Bertelsen (1951) made it clear that ". . . the sep- 

 aration of the species is still very uncertain and 

 future investigations and material will probably 

 make it necessary to revise this synopsis." 



At the time of Bertelsen's (1951) monograph on 

 the Ceratioidei, 19 metamorphosed melanocetid 

 males were known. Of these, 14 had been set up as 

 tjrpes of 12 separate species, and 5 were uncer- 

 tainly placed. On the basis of subdermal pigment, 

 fin ray counts, and geographic distribution, Ber- 

 telsen (1951) synonymized 6 of these 12 nominal 

 forms with M. johnsoni and 4 with M. murrayi. 

 The remaining two species based on males, M. 

 longirostris and M. nudus, each differing slightly 

 from the rest of the material, were tentatively 

 retained (Table 1). 



With the vast increase in the amount of mate- 

 rial of Melanocetus made available in the last 25 



59 



