Gymnothorax javanicus ( Bleeker 1859 )

Smith, David G., Bogorodsky, Sergey V., Mal, Ahmad O. & Alpermann, Tilman J., 2019, Review of the moray eels (Anguilliformes: Muraenidae) of the Red Sea, with description of a new species, Zootaxa 4704 (1), pp. 1-87 : 35-37

Gymnothorax javanicus ( Bleeker 1859) —Giant Moray

( Figure 21 )

Muraena javanica Bleeker 1859: 347 ( Patjitan , Java, Indonesia). Holotype (unique), BMNH 1867.11.28.214.— Klunzinger, 1871: 616.

Lycodontis javanicus: Dor 1984: 28 .

Gymnothorax javanicus: Goren & Dor 1994: 7 ; Randall & Golani 1995: 861; Debelius 1998: 11, 12; Khalaf 2004: 36; Lieske & Myers 2004: 36; Golani & Bogorodsky 2010: 10; Golani & Fricke 2018: 21.

Red Sea material. Sudan: BPBM 17901 (1, 156), Suakin Archipelago; SMF 7464 (1, 550), Sanganeb Atoll. Saudi Arabia: KAUMM 398 [ KAU 13-206] (1, 680), Al Wajh; SMF 35386 [ KAU 13-355] (1, 230), Al Wajh; SMF 35812 [ KAU 12-1087] (1, 211), Al Lith; SMF 35813 [ KAU 13-202] (1, 610), Al Wajh; USNM 147424 (4, 312–605), Jeddah; USNM 147426 (1, 281), Jeddah. Eritrea: USNM 312505 (1, 718), Massawa.

Comparative material. Indonesia: BMNH 1867.11 .28.214 (1, 718, holotype) . French Polynesia, Manua’e (Scilly) Atoll: USNM 435186 [SCIL-297] (1, 242) . Gambier Is. USNM 438468 [GAM-646] (1, image only, specimen not retained) .

Description. In TL: preanal length 2.0–2.2, predorsal length 7.9–10, head length 6.6–8.1, body depth at anus 16–24. In head length: snout length 5.6–6.5, eye diameter 9.3–13, upper-jaw length 2.5–2.9. Pores: LL 2, SO 3, IO 4, POM 6. Vertebrae: predorsal 5–7, preanal 60–61, total 137–141.

Body moderate to robust, the depth increasing with growth; anus at or slightly before midlength; dorsal-fin origin before gill opening. Jaws moderate, of equal length. Eye moderate, over middle of upper jaw. Anterior nostril tubular; posterior nostril with a raised rim, above or slightly behind anterior margin of eye.

Teeth smooth, slender and pointed or blade-like. Intermaxillary teeth in a single peripheral series, 4–5 on each side sometimes with a few much smaller teeth between; 2–3 median teeth. Maxillary teeth uniserial except in small specimens, which may have 1–3 larger inner teeth anteriorly, and about 13–15 smaller teeth in outer row. Dentary with 2–3 larger inner teeth anteriorly and about 10–20 smaller outer teeth. Vomerine teeth biserial anteriorly.

Color: body and fins brown, with small, darker brown or black markings consisting of subquadrate to irregular spots (those dorsally are larger), sometimes with a pale center, in approximately three irregular rows. Head usually darker than body. Small specimens have a lighter background color with broadly spaced, obvious, round spots, most of them larger than eye. Large specimens tend to be darker overall with smaller spots. Gill opening in a conspicuous dark spot. Iris brown.

Maximum size 2 m or greater.

Distribution and habitat. Widely distributed throughout the Indo-Pacific region from the Red Sea and east coast of Africa east to the Hawaiian Islands, Line Islands, and Pitcairn Islands, also reported from Costa Rica and Panama in the eastern Pacific. Common on coral reefs and rocky substrata, at depths of 0– 46 m.

Remarks. This is the largest of all moray species in terms of weight. Adults can reach more than 2 m in length and weigh as much as 70 kg. Due to their large size and piscivorous habits, they can be a serious source of ciguatera poisoning and should not be eaten. Little geographic variation is evident from the morphology of the species. However, in the phylogenetic analysis two weakly diverging subclades were evident with comparatively little divergence within the two subclades ( Fig. 48 ). However, the clades did not represent biogeographic subgroupings, as sequences from the Southern Pacific were present in both subclades. The sequence of a specimen from the Red Sea (SMF 35386) collected in the present study formed part of a subclade, in which another Indian Ocean sequence (from Madagascar) was included. This preliminary observation certainly is interesting and as more data become available, it would be worthwhile investigating the nature of the apparent genetic divergence among specimens of G. javanicus observed in this study. Concerning close affiliations at the species level, G. javanicus was included in one clade with G. flavimarginatus that received moderately high support from bootstrapped analyses in the present phylogeny.

Figures

FIGURE 21. Gymnothorax javanicus. A: adult, Sharm el Moya, Egypt; B: SMF 35812 [KAU12-1087], juvenile, 211 mm TL, Al Lith, Saudi Arabia. Photos by S.V. Bogorodsky.

FIGURE 48. Unrooted maximum likelihood phylogeny of Indo-Pacific moray eels (Muraenidae) based on partial mitochondrial COI. Branch support values were obtained by 100 bootstrapped replicates; only bootstrap values above 50 percent are shown. The scale bar represents average number of nucleotide substitutions. (A) = specimen sequenced in this study; (B) = sequence retrieved from BOLD; (C) sequence retrieved from CRIOBE; (G) = sequence retrieved from GenBank; (R) = sequence retrieved from Reece et al. (2010); (ID) = species ID re-assigned herein; (ID-H) = specimen re-assigned as of Huang et al. (2019); (SAU) = collected in Saudi Arabia; (ISR) = collected in Israel.