FISHERY BULLETIN: VOL. 75, NO. 4 



spots on upper back on middle-third of body (see 

 Figure 4). A narrow dark streak on back at base of 

 dorsal, broadening on narrow part of tail. Indi- 

 viduals of about 35 mm SV differ in that the body 

 is not so deep, and there is little or no pigment. 

 Also the dorsal is relatively higher. Our smallest 

 specimen, 18.5 mm SV, has the back with a 

 straight taper behind the head, the ventral profile 

 more evenly tapering, and has scattered 

 melanophores on the head and over the viscera. 

 These probably represent the larval pigmenta- 

 tion. 



Identification and remarks. — The characters 

 given in the generic and specific diagnoses serve to 

 distinguish D. lorum adequately from all known 

 trachipterids. In addition to the characters given 

 in the diagnoses, the two species of Desmodema 

 differ in number of dorsal rays. The single D. 

 lorum counted had 197 dorsal rays and three D. 

 polystictum had 120, 124, and 121, respectively. 

 Another feature is the height of the dorsal. Large 

 D. lorum have proportionately longer dorsal rays 

 than do D. polystictum of equivalent size (Figure 8, 

 Table 1). Prejuveniles of D. lorum can most easily 

 be distinguished from those of D. polystictum by 

 their deeper body, and more rounded anteroven- 

 tral contour (Figure 4). 



E 

 E 



>- 

 < 



< 



CO 



<r 

 o 



Q 



li- 

 CO 



X 



z 



Id 



20 



30 40 50 60 70 



HEAD LENGTH (mm) 



Rw 



90 



FIGURE 8. — The regression of length of longest dorsal ray on 

 head length in Desmodema. Open circles D. polystictum, closed 

 circles D. lorum. 



Although Ogilby did not illustrate the holotype 

 of Tnachypterus jacksoniensis polystictus, his de- 

 scription is sufficiently detailed to allow iden- 

 tification with considerable certainty. The polka- 

 dotted coloration and lack of lower caudal lobe are 

 diagnostic of Desmodema, and the dorsal ray 

 count of 126 indicates that our material has been 

 correctly assigned. The caudal count of seven or 

 eight rays also accords with our concept of D. 

 polystictum. Tanaka's ( 1908) excellent figure indi- 

 cates that Trachypterus misakiensis has properly 

 been synonymized with D. polystictum, and the 

 presence of eight caudal rays in the small holotype 

 of Trachipterus deltoideus dictates a similar 

 placement. 



Etymology. — From the Latin lorum, a whip, in 

 reference to the elongate tail. Suggested common 

 name, whiptail ribbonfish. 



Material examined.— Holotype: USNM 216726, 

 formerly SIO 62-434, a 1,098 mm SL (276 mm SV) 

 male, taken between 29°05'N, 126°37'W and 

 29°03'N, 126°42'W by RV John N. Cobb with a 

 Cobb Mk II trawl with 1,200 m wire out (esti- 

 mated fishing depth 400 m) between 1930 and 

 2110 h on 25 August 1962. (Original station 

 number 90.160, C6208, see Berry and Perkins 

 1966.) Paratypes: LACM 30217-1, 34°42'N, 

 121°20'W, spit up by Thunnus alalunga, 1(91.5, 

 167); LACM 9890-2, 34°25'N, 120°28'W, 15.2-m 

 midwater trawl, 8 fm, 1(97, 173); LACM 9982, 

 33°00'N, 118°03'W, IKMT, 2,743 m wire out, 

 1(131); SIO 76-335, 13 km west of Oceanside, 

 Calif., bait net, 1(95, 198); LACM 30597-1, 

 32°48'N, 118°16'W to 32°30'N, 118°30'W, IKMT, 

 1(87, 188); LACM 35237-1, 32°43'N, 118°57.5'W, 

 10-m midwater trawl, 1(103.7, 412); LACM 

 31678-1, San Clemente Island, Calif., off Pyramid 

 Head, 1(83); LACM 30998-1, 31°45'N,118°48'W to 

 31°44'N, 118WW, IKMT, 1,300 m, 1(93); SIO 

 63-375, 31°40.5'N, 122°03.5'W to 31°37.0'N, 

 122°04.3'W, Cobb Mk II trawl, 1,144 m wire out, 

 1(139.8, 580); SIO 63-429, 29°58.5'N, 120°07'W, 

 IKMT, 4,500 m wire out, 1(173); LACM 9726-8, 

 29°29'N, 118°35'W, IKMT, 2,134 m wire out, 

 1(92.5, 189); SIO 74-47, 28°10.2'N, 160°00.9'E, 

 IKMT, 0-1,000 m, 1(125, 364); UCLA W61-125, 64 

 km off Cabo Colnett, Baja California, 1(286), 

 LACM 31800-2, 129 km south of Cabo San Lucas, 

 Baja California, 1(283). 



Additional material. — UCLA W55-320, 



854 



