STRUHSAKER: ARC YRtPNUS BROCKI NEW SPECIES 



long. 156°45.9'W), 2028-2228, 31 October 1967, 

 248 m, 12.5-m ST. TC-33-25 (3), Kealaikahiki 

 Channel (lat. 20°43.3'N, long. 156°48.6'W), 

 0150-0250, 4 November 1967, 224 m, 8-m ST. 

 TC-33-37 (2), Kealaikahiki Channel (lat. 20° 

 41.7'N, long. 156°39.8'W), 1747-1836, 9 No- 

 vember 1967, 276 m, 8-m ST. TC-35-8 (1), 

 northeast coast Hawaii Island (lat. 19°54'N, 

 long. 155°03.1'W), 1804-1930, 29 March 1968, 

 280 m, 12.5-m ST. TC-35-36 (1), north edge 

 Penguin Bank (lat. 21 °10.2'N, long. 157°24.9'W), 

 0435-0625, 8 April 1968, 183 m, 12.5-m ST. 

 TC-36-23 (22), north edge Penguin Bank (lat. 

 21°09.7'N, long. 157°25.2'W), 2019-2149, 4 

 March 1968, 183 m, 12.5-m ST. TC-36-35 (20), 

 north edge Penguin Bank (lat. 21°09.7'N, long. 

 157°24.9'W), 0114-0245, 5 May 1968, 183 m, 

 12.5-m ST. TC-40-10 (7), north edge Penguin 

 Bank (lat. 21°09.8'N, long. 157°24.4'W), 2021- 

 2211, 7 November 1968, 181 m, 12.5-m ST. TC- 

 40-26 (1), north edge Penguin Bank (lat. 21° 

 09.8'N, long. 157°24.2'W), 2023-2124, 10 No- 

 vember 1968, 183 m, 12.5-m ST. TC-40-61 (5), 

 Pailolo Channel (lat. 21°02.1'N, long. 156° 

 44.4'W), 2026-2126, 18 November 1968, 238 m, 

 12.5-m ST. These specimens, and those taken at 

 the same stations as specimens in the type 

 series, are in the collections of the Southwest 

 Fisheries Center, Honolulu Laboratory, Na- 

 tional Marine Fisheries Service, NOAA. 



Diagnosis 



A. brocki is morphologically closest to A. 

 ephippiafKs and A. iride.sceits. These three spe- 

 cies differ markedly from A. atlaiiticus in hav- 

 ing fewer photophores in the VAV -I- anterior 

 AC series and the posterior AC series. They 

 usually have fewer gill rakers, pectoral rays, 

 and vertebrae (Table 1). They have shorter 

 snouts and longer upper jaws than A. atlanticus. 

 The anal fins in A. brocki, A. ephippiatu.s, and 

 A. iridescois originate below the posterior half 

 of the dorsal fin bases, whereas the anal fin 

 in A. athuiticus originates nearly below the 

 origin of the dorsal fin. 



Coioits. — A. brocki exhibits clearcut differ- 

 ences from the three nominal species of this 

 genus in having fewer photophores in the VAV 

 + anterior AC series (17 or less in s])ecimens 



40 mm SL or longer. Figure 2, as compared 

 with 18-28), fewer photophores in the posterior 

 AC series (9-11 as compared with 12-18), fewer 

 gill rakers (15-17 as compared with 18-26), 

 and fewer vertebrae (41-43 as compared with 

 44-46). 



Meai^urcnicHts. — A. brocki differs from A. 

 ephippiatus in possessing a smaller bony orbit, 

 greater interorbital distance, and (in speci- 

 mens longer than 70 mm SL) a greater distance 

 from snout to anal fin origin. It differs from 

 A. atlanticus in possessing a greater inter- 

 orbital distance, longer snout, longer upper 

 jaw (and accordingly, a longer premaxillary 

 and maxillary), a greater body depth, longer 

 dorsal fin base, and a greater snout to anal fin 

 origin distance. It differs from A. iridescois 

 in that it possesses a greater interorbital dis- 

 tance. 



Description 



Meristics. — The meristics for the 20 speci- 

 mens in the type series are summarized below 

 and in Table 1. Supplementary counts for cer- 

 tain characters were obtained from specimens 

 not included in the type series. The number of 

 specimens having a particular count is given 

 in parentheses. Occasionally, only one side of 

 bilaterally symmetrical structures could be 

 counted. 



Gill rakers on first arch (counts for the right 

 upper and lower limbs given first): 4/4 + 

 11/11(1), 4/4 + 11/12(1), 4/4 + 12/12(12). 

 4/5 + 12/12(2), 4/4 + 12/3(2), 5/5 _+ 12/ 

 12(2). The four specimens with five gill rakers 

 on the upper limb were small, being 41-56 mm 

 SL. Pelvic rays: 7(19). Caudal rays (primary): 

 10 superior, 9 inferior (20). Branchiostegals: 

 7 + 3 = 10(20). 



Only the combined VAV -I- anterior AC and 

 the posterior AC series of photophores exhibit 

 variation. ORB: 1/1(20). OP: 3/3(20). BR: 

 6/6(44). IV series — IP: 6/6(43), PV: 10/10 

 (43). OA: 7/7(44). Middle AC: 5/5(44). Pos- 

 terior AC 9-11 (Table 1). There is no obvious 

 relation between specimen size and numbers 

 of posterior AC photophores. The number of 

 photophores in the VAV -I- anterior AC series 

 increases with size until the full complement 



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