Conger macrocephalus Kanazawa, 1958

Smith, David G. & Ho, Hsuan-Ching, 2018, Review of the congrid eel genus Conger (Anguilliformes: Congridae) in Taiwan, Zootaxa 4454 (1), pp. 168-185 : 176-178

Conger macrocephalus Kanazawa, 1958

Figs. 3C , 5 ; Table 1

Conger macrocephalus Kanazawa, 1958:254 , pl. 1, fig. M (type locality: Verde Island passage, Luzon Island, Philippines, 13°34'37"N, 121°07'30"E, Albatross station 5367, depth about 180 fathoms. Holotype: USNM 164334). Ho et al., 2015:146.

Conger japonicus (not of Bleeker, 1879, part).? Chen & Weng, 1967:49;? Chen, 1969: 132;? Shen, 1984:112;? Shen, 1988:15;? Shen et al., 1993:116;? Chen, 2004:32;? Ho et al., 2010:table 1.

Conger wilsoni (not of Bloch & Schneider, 1801):? Chen & Yu, 1986:252.

Conger conger (not of Linnaeus, 1758):? Lee & Yang, 1966:56, fig. 5.

Specimens examined. 42 specimens, 286‒822 mm TL. Taiwan: * NMMB-P3365 (1, 415) , Taiwan, no further data. * NMMB-P4531 (1, 551), Hsiao-liu-chiou, Pingtung, 10 Mar. 1966 . * NMMB-P6117 (4, 286‒351), Daxi , Yilan, 8 May 2003 . * NMMB-P11166 (2, 365‒462), Dong-gang , 15 Dec. 2009 . * NMMB-P11178 (1, 294), Donggang , 13 Sep. 2010 . * NMMB-P11183 (1, 475), Dong-gang , 15 Dec. 2010 . * NMMB-P11907 (1, 491), Dong-gang , 26 Feb. 2011 . * NMMB-P11922 (1, 315), Dong-gang , 28 Jan. 2011 . * NMMB-P13157 (1, 466), Dong-gang , 12 Sep. 2009 . * NMMB-P13866 (2, 470‒479), Dong-gang , 10 Aug. 2011 . * NMMB-P14069 (2, 432‒663), Changbin , Taitung, 15 Sp. 2011. * NMMB-P15401 (1, 391), Changbin , Taitung, 30 Sep. 2011. * NMMB-P16550 (3, 412‒502), Changbin , Taitung, 15 Feb. 2012 . NMMB-P23926 (2, 408‒424), Dong-gang , 17 Feb. 2016 . NMMB-P24026 (1, 326), Dong-gang , 13 Mar. 2015 . NMMB-P24860 (1, 363), Ke-tzu-liao, Kaohsiung, 2 Apr. 2015 . * USNM 398727 (1, 333), Dong-gang , 10 Nov. 2009 . *USNM 398808 (1, 443), Taiwan , 7 Feb. 2007. * USNM 398809 (1, 434) , Taiwan, no date. * USNM 401056 (1, 562), Dong-gang , 8 Nov. 2009 . * USNM 401077 (4, 393‒506), Dong-gang , 14 Nov. 2009 . * USNM 404406 (1, 816), Dong-gang , 8 Nov. 2009 . USNM 437347 (1, 373), Dong-gang , 22 May 2014 . * USNM 437348 (2, 350‒425), Dong-gang , 6 Nov. 2015. Tentative identification . NMMB-P282 (dried out). Other localities: Philippines : USNM 164334 (1, 796, holotype), Verde Island Passage, 13°34’ 37”N, 121°07’30”E, 180 fathoms (329 m), 22 Feb 1909 . USNM 438040 (1, 558), Negros Oriental, Dumaguete , 10 Jul 2015 . USNM 438049 (1, 434), Negros Oriental, Dumaguete , 5 Feb 2013 . Oman: USNM 410631 (1, 495), 16°23’19.11”N, 54°34’52.02”E, 2007. Samoa: ANSP 146127 (1, 822), no other data.

Diagnosis. Head very long, 15.4‒17.7% TL, 38.0‒44.8% PAL. DFO over posterior half to tip of pectoral fin. Inner row of dentary teeth longer than half of outer row ( Fig. 3C ). Vertebrae 132‒139.

Description. See Table 1 for morphometric data. Lateral-line pores: prepectoral 5‒6; predorsal 12‒15; preanal 32‒38; total 121‒133. Head pores: SO 4, IO 6 (5 on upper jaw + 1 behind rictus), POM 9 (rarely 10, 6 on lower jaw, 3 behind rictus), ST 1. Vertebrae: predorsal 13‒16; preanal 34‒39; total 132‒139; MVF 14‒37‒136.

DFO over posterior part of pectoral fin. Angle of jaw before posterior margin of eye, 6th IO pore at level of and more than one pore diameter behind rictus. Two rows of teeth on each jaw; inner row of maxillary teeth about half length of outer row, inner row of dentary teeth longer than half length of outer length. When fresh, uniformly brown with black margins on median fins; pectoral fin pale or with a large black patch. When preserved, uniformly pale grayish to brownish, ventral surface slightly paler; pectoral fin grayish; median fins white with black margins, the black margins on posterior portion broader.

Maximum size at least 822 mm TL based on our examination.

Distribution. Kanazawa (1958) described this species based on a single specimen collected from the Philippines. Ho et al. (2015) first reported it from Taiwan, where it was previously misidentified as Conger japonicus . Smith et al. (2017) reported a specimen from Oman in the northwestern Indian Ocean and suggested that the specimen recorded from Réunion by Quero & Saldanha (1995) as Conger wilsoni might be C. macrocephalus instead, based on its relatively long head (17% TL) and low vertebral count (138). In addition, we have examined a specimen from Samoa that also appears to be C. macrocephalus (head length 17% TL, vertebrae 138). The species thus seems to occur over a wide area of the tropical Indo-Pacific.

Remarks. Conger macrocephalus is the most common species found in Taiwan. It is characterized by an especially large head, head length 15.4‒17.7% TL compared to 11.5‒14.9% TL in the other species in Taiwan. Although Kanazawa (1958) described the DFO over the pectoral fin, we found our specimens with the location of the DFO ranging from the middle of the pectoral fin to slightly behind the tip of the fin.

Genetic data are available for USNM 398727, 401056, and 404406 under Genbank accession numbers MF172254 ‒ MF172256 .

Figures

FIGURE 3. Demonstration of jaw tooth pattern of five Conger species in Taiwan. A. C. cinereus, from NMMB-P24265. B. C. jordani, from NMMB-P24766. C. C. macrocephalus, NMMB-P15401. D. C. myriaster, NMMB-P6392. E. C. philippinus, NMMB-P22425. Note that the numbers of principal teeth are not counted from the specimens.

FIGURE 5. Conger macrocephalus Kanazawa, 1958. A–B. NMMB-P24026, 326 mm TL. Bars indicate origins of dorsal fin (above) and anal fin (below).