PIETSCH and VAN DUZER: SYSTEMATICS AND DISTRIBUTION OF ANGLERFISHES 



fused the hypural plate, Pietsch 1972a) of which 

 13-15 are caudal vertebrae (those bearing com- 

 plete haemal arches). Epurals are absent. The 

 hypural plate is unnotched posteriorly and bears 

 the overlapping bases of nine principal caudal 

 rays, the uppermost of which is exceptionally 

 large. The uppermost and two lowermost caudal 

 rays are simple, the central rays are bifurcated 

 distally. 



Median fins and illicial apparatus (Figures 14, 

 15). — There are 13-19 biserial, segmented, and 

 unbranched dorsal fin rays, the number varying 

 somewhat among species. The rays are supported 

 by elongate, closely associated radials, usually one 

 less than the number of rays. All species of the 

 genus have 4 anal fin rays (of 353 specimens 

 counted, only 2 had 3 anal rays, and only 2 had 5 

 rays) that are like those of the dorsal fin, invari- 

 ably supported by 3 similar, closely associated ra- 

 dials (Table 2, Figure 14). 



The pterygiophore of the illicium is strongly 

 compressed with a thin, bladelike ventral expan- 

 sion. The length of the pterygiophore varies from 

 17*7^ SL in M. murrayi to 33% SL in M.johnsoni. 

 The remnant of the second cephalic ray is a minute 

 ossification lying on the pterygiophore just behind 

 the articulation with the illicial bone (Figure 15). 

 The length of the illicial bone varies slightly 

 among Melanocetus species, becoming longer pro- 

 portionately with growth. 



Pectoral girdle, pectoral fin, and pelvic bone (Fig- 

 ure 16). — Each posttemporal overlaps the re- 

 spective pterotic, epiotic, and exoccipital. It is in 

 turn overlapped by the parietal in M.johnsoni, hut 

 widely separated from this bone in M. murrayi. 



An ossified posteroventral process of the 

 coracoid is absent but perhaps represented by a 

 posteroventral cartilaginous extension. There are 

 four pectoral radials, the lower two of which be- 

 come completely fused with each other giving the 

 appearance of only three radials (Regan and Tre- 

 wavas 1932, fig. 22; Pietsch 1972a). 



The pectoral fin lobe of M. murrayi is consid- 

 erably smaller than that of other Melanocetus 

 species (Figure 16 A). In other ways the elements 

 of the pectoral girdle, pectoral fin, and pelvic bone 

 do not differ substantially from those of oneirodids 

 (Pietsch 1974). 



Skin spines. — Minute dermal spines (approxi- 

 mately 0.03-0.1 1 mm long) are present in the skin 



Illicial 

 bone 



Remnant of 2nd 

 cephalic ray 



Pterygiophore 

 of illicium 



Figure 15. — Bones of illicial apparatus of Melanocetus murrayi, 

 LACM 31501-3, 84 mm SL, left lateral view. Cartilage stippled. 



of the two species examined osteologically. In M. 

 johnsoni they are most numerous on the side of the 

 trunk under the dorsal fin ( where there are about 6 

 spines/mm2)but become progressively more 

 widely scattered anteriorly and finally disappear 

 in the area of the upper and lower jaws 

 (Struhsaker 1962). In the two specimens of M. 

 murrayi examined osteologically the spines are 

 confined to the caudal peduncle. 



SYSTEMATICS 



Family Melanocetidae Regan 1912 



Type genus Melanocetus Giinther 1864 



Diagnosis. — The metamorphosed females of the 

 Melanocetidae are distinguished from those of all 

 other ceratioid families by having the following 

 combination of characters: jaws equal anteriorly; 

 supraethmoid present; parietals present; ptero- 

 sphenoid present; anterior maxillomandibular lig- 

 ament absent (Pietsch 1972a); hyomandibular 

 with a double head; hypohyals 2; branchiostegal 

 rays 6; operculum bifurcate, upper fork reduced; 

 suboperculum slender, as long as lower fork of 

 operculum, with strong anterior spine; pharyn- 

 gobranchials I and IV absent; epibranchial I 

 reduced; a single ossified basibranchial; 

 epibranchial and ceratobranchial teeth absent; 

 epurals absent; only an ossified remnant of second 

 cephalic ray present; dorsal fin rays 13-17, anal fin 



67 



