FISHERY BULLETIN: VOL. 78, NO. 1 



Xenoceratias regani Koefoed 1944:4, 6, pi. 1, fig. 6 

 (original description, single specimen, holotype 

 UBNM 4311, 20 mm, Michael Sars North At- 

 lantic Deep-Sea Expedition stn. 53, central 

 North Atlantic, 34°59' N, 33°01' W, 2,600 m 

 wire, bottom depth 2,615-2,865 m, 8-9 June 

 1910). 



Melanocetus murrayi, Bertelsen 1951:44-48, fig. 

 16A, D, F, H, table 5 (synonymy, description, 

 comparison with all known material, in key); 

 Grey 1956:235 (synonymy, distribution); Maul 

 1962b:37-38, fig. 3 (description of additional 

 specimen); Maul 1973:667 (synonymy, after 

 Bertelsen 1951). 



Material. — Metamorphosed females, 140 (13.5- 

 120 mm): BMNH, 8 (21-57 mm); BOC, 1 (15 mm); 

 CAS, 3 (14.5-51 mm); FSM, 6 ( 13.5-54 mm); lOAN, 

 5 (14-56 mm); lOS, 6 ( 17-68 mm); ISH, 33 ( 15-120 

 mm); LACM, 14 ( 13-84 mm); MCZ, 14 (13-84 mm); 

 UMML, 28 (17-99 mm); USNM, 7 (15-78 mm); 

 VIMS, 1 (33 mm); ZMUC, 14 (14-80 mm). 



Diagnosis. — A species of Melanocetus unique in 

 having the following combination of characters: 

 anterior margin of vomer deeply concave (Figure 

 2); least outside width between frontals 9.1-17.8% 

 SL (Figure 19); number of lower jaw teeth 46-142 

 (Figure 20); longest lower jaw tooth 7.7-16.7% SL; 

 width of pectoral fin lobe 6.1-8.9% SL; escal bulb 

 width 1.9-5.1% SL; illicium length 23.1-37.2% SL; 



esca with crests minute or absent (Figure 29); mi- 

 nute skin spines restricted to caudal peduncle; 

 integument relatively thin (0.48 mm). 



Description. — Escal bulb not compressed, with a 

 low, rounded distal prolongation usually unpig- 

 mented on tip; posterior and anterior crests mi- 

 nute or absent (Figure 29); integument thin, 

 easily torn (cross sections measure 0.48 mm in 

 thickness), pigment readily lost during fixation 

 and preservation, often transparent, especially in 

 gill region and over branchiostegal rays. 



Number of upper jaw teeth 34-178; dorsal fin 

 rays 12-14, pectoral fin rays 15-19 (rarely 20) (Ta- 

 ble 2). 



Distribution. — Melanocetus murrayi has a wide 

 horizontal distribution in the Atlantic and Pacific, 

 but is apparently absent from the Indian Ocean 

 (see Distribution, p. 83). Compared with M. 

 johnsoni, it is a much deeper living form: only 10% 

 of the material (for which data was available) was 

 captured in open nets fished at maximum depths of 

 <l,000m. Approximately 58% of the material was 

 taken by gear fished at maximum depths of 1,500 

 m or below, and 45% by gear fished at 2,000 m or 

 below (see Distribution, p. 83). The relatively thin 

 integument of M. murrayi (less than one-third the 

 thickness of that of its congeners) as well as a 

 lighter, less well-ossified skeleton reflects the 

 poorer trophic economies of these greater depths 

 (see Description above). 



1 mm 



.5 mm 



FIGURE 29.— Escae of Melanocetus murrayi: A. ISH 2961/71, 58 mm SL; B. ISH 922/68, 70 mm SL; C. ISH 2961/71, 76 mm SL; D. ISH 



c(75/-,3. 120mmSL. 

 82 



