Dysomma polycatodon Karrer, 1983

Ho, Hsuan-Ching, Smith, David G. & Tighe, Kenneth A., 2015, Review of the arrowtooth eel genera Dysomma and Dysommina in Taiwan, with the description of a new species (Anguilliformes: Synaphobranchidae: Ilyophinae), Zootaxa 4060 (1), pp. 86-104 : 99

Dysomma polycatodon Karrer, 1983

Fig. 7 ; Table 3

Dysomma polycatodon Karrer, 1983:89 (type locality: Northwestern Madagascar, 15°21'S, 46°11'E, depth 170–175 m). Robins & Robins, 1989:250. Smith, 1999:1661. Chen & Mok, 2001:79.

Specimens examined. Collected from Daxi fishing port, NE Taiwan, bottom trawl: ASIZP 60188 (1 spec., 453 mm TL), 15 Oct. 1997. NMMB-P384 (1, 326), 23 Jan. 1994. NMMB-P11120 (1, 544), 6 Sep. 2010. USNM 372011 (1, 362), 12 Sep 1998. USNM 398475 (1, 384), 10 Sep. 2007. Collected from Dong-gang fishing port, SW Taiwan, bottom trawl: ASIZP 55560 (1, 358), 15 Jan. 1981. NMMB-P2843 (1, 505), 100 m, 8 Nov. 2001. NMMB- P3652 (1,321), 150 m, 28 May 2012. NMMB-P9076 (1, 250), 13 Jun. 2008. NMMB-P11128 (2, 310–333), 13 Sep. 2010. NMMB-P11129 (1, 400), 13 Sep. 2011. NMMB-P11132 (1, 365), 6 Sep. 2010. NMMB-P12070 (1, 550), 18 Feb. 2011. NMMB-P12625 (2, 372–375), 25 Mar. 2011. NMMB-P15256 (1, 407), 28 Oct. 2011. NMMB-P15625 (2, 367–371), 25 Mar. 2011. NMMB-P16388 (1, 274), 21 Feb. 2012. NMMB-P17776 (1, 344), 9 Aug. 2012. NMMB-P17783 (1, 544), 9 Aug. 2012. NMMB-P18040 (3, 500–600), no date. NMMB-P19278 (1, 260), 10 Nov. 2011. USNM 398736 (1, 196), 14 Nov. 2009. USNM 398737 (1, 265), 14 Nov. 2009. USNM 402447 (5, 275–362), Nov. 2009. USNM 410020 (1, 382), 26 Feb. 2011. USNM 427171 (1, 311), 16 Nov. 2011. Collected from Shiaoliu-chiu, SW Taiwan: NMMB-P3415 (1, 355), 26 Dec. 2003.

Other localities. Philippines: USNM 344108 (1, 436), 23 Sep. 1995. Madagascar: MNHN 1979–0003 (1, 523), holotype, 15°19'58.8"S, 46°11'2.4"E, 170–175 m, 19 Jan. 1979.

Diagnosis. Pectoral fin present; dorsal-fin origin anterior tolevel of pectoral fin base, predorsal length 10.0– 12.9% TL; anus anterior, just below pectoral fin, preanal length 15.5–18.2% TL; trunk very short, trunk length 2.4– 3.9% TL; 2 intermaxillary teeth; 3 compound teeth on vomer; 3 or 4 rows of small sharp teeth on upper jaw; single row of 2 large anterior teeth followed by 22–31 small sharp teeth on lower jaw; head pores: IO 4, SO 3, M 6, POP 0 (1 with 1), AD 1 (1with 0); lateral-line pores: predorsal 3–5, prepectoral 5–7, preanal 8–11, and total 65–78, the last at about anterior two-thirds of total length; MVF 8-13-130, total vertebrae 128–133 (1 with 120). Body light grayish to brown dorsally, paler ventrally; posterior half of anal-fin base deep brown, and dorsal and anal fins with white margins.

Remarks. The holotype of this species, collected off Madagascar, has 140 vertebrae ( Karrer, 1983), significantly more than the specimens from Taiwan (128–133). One of two specimens in NMMB-P18040 has only 120 total vertebrae. However, no other difference can be observed and the vertebrae appear to be complete. This specimen may represent a different species when more specimens are available.

Figures

FIGURE 7. Dysomma polycatodon Karrer, 1983, NMMB-P 11128, 1 of 2, 333 mm TL, collected from Dong-gang fishing port.