Gymnothorax flavimarginatus (Rüppell 1830) —Yellowmargin Moray

(Figure 15)

Muraena flavimarginata Rüppell 1830: 119, pl. 30 (fig. 3) (Red Sea). Holotype (unique), SMF 765. — Klunzinger 1871: 615.

Gymnothorax flavimarginatus: Marshall 1952: 223; Tortonese 1955: 51; Goren & Dor 1994: 7; Randall & Golani 1995: 858; Debelius 1998: 13; Khalaf 2004: 35; Lieske & Myers 2004: 36; Golani & Bogorodsky 2010: 10; Golani & Fricke 2018: 21.

Lycodontis flavimarginatus: Roux-Estève 1956: 62 (as flavomarginatus); Dor 1984: 27.

Red Sea material. Red Sea: SMF 765 (1, 550, holotype). Sudan: BPBM 19734 (1, 195), one mile north of Port Sudan . Saudi Arabia: SMF 35172 [KAU 13-583] (1, 317), Duba; USNM 147422 (2, 233–554), 2 km north of Jeddah; USNM 147429 (3, 254–307), 5 km north of Jeddah. Eritrea: USNM 312430 (7, 150–286), Difnein Island; USNM 312453 (3, 261–412), Difnein Island.

Comparative material. Mauritius: MNHN B-2468 (1, 450, lectotype of Muraena mauritiana Kaup) ; MNHN A-3738 (1, 300, paralectotype of Muraena mauritiana Kaup) . MCZ 6146 (1, 215, holotype of Gymnothorax viridipinnis Bliss) . Taiwan: USNM 312225 (2, 74–82) . Indonesia: BMNH 1867.11 . 28.253 (1, 464, holotype of Muraena batuensis Bleeker). Micronesia: USNM 323385 (1, 75) . Fiji: USNM 312700 (2, 75–84); USNM 410229 (1, 128) . Tonga: USNM 334796 (1, 103) . Hawaii: USNM 50619 (1, 590, holotype of Gymnothorax thalassopterus Jenkins).

Description. In TL: preanal length 2.0–2.3, predorsal length 8.3–11, head length 7.5–11, body depth at anus 14–27. In head length: snout length 4.8–6.5, eye diameter 6.9–12, upper-jaw length 2.1–2.7. Pores: LL 2, SO 3, IO 4, POM 6. Vertebrae: predorsal 4–6, preanal 54–58, total 130–139.

Body moderately elongate; anus usually 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 and behind anterior margin of eye.

Teeth smooth, slender, conical to triangular. Intermaxillary teeth in a single peripheral series, usually 2 median teeth. Maxillary teeth biserial, inner teeth fewer and larger. Dentary teeth biserial anteriorly, with 2–4 large inner teeth, uniserial posteriorly. Vomerine teeth uniserial.

Color: yellowish, densely and finely mottled with dark brown spots sometimes in gravel-like pattern, often to the extent that little of the pale yellowish ground color remains; small specimens with spots larger and more widely spaced; snout, front of lower jaw, and anterior nostril purplish brown; a black blotch over gill opening; fins dark basally with a conspicuous greenish yellow or yellow margin posteriorly.

Maximum size at least 1.2 m.

Distribution and habitat. Widely distributed across the Indo-Pacific, from the Red Sea and east coast of Africa east to the Hawaiian Islands and French Polynesia, and islands off Central America. Occurs on coral and rocky reefs from depths of 0.5–150 m, usually 5– 30 m.

Remarks. There is little difference in the vertebral counts between specimens from the Red Sea (130–134) and those from elsewhere (131–139). The second author once observed this species at Ras Muhammad in a feeding association with the jackfish Caranx melampygus, in which the latter fed on prey driven from hiding places by the eel. The phylogeny (Fig. 48) shows that G. flavimarginatus is closest related to G. javanicus, although bootstrap support for this relationship is only moderately high in the present phylogeny based on partial mitochondrial COI. High support for the close phylogenetic relation of these two species, however, was shown in a multigene phylogeny by Reece et al. (2010).