Gymnothorax arabicus, Smith & Bogorodsky & Dandar & Zajonz, 2024

Smith, David G., Bogorodsky, Sergey V., Dandar, James & Zajonz, Uwe, 2024, A new species of short unpatterned moray eel (Anguilliformes: Muraenidae) from the northwestern Indian Ocean, including the Socotra Archipelago, with a redescription of Gymnothorax pseudoherrei Böhlke, Zootaxa 5477 (4), pp. 465-474 : 468-471

Gymnothorax arabicus sp. nov.

Arabian false brown moray

( Figures 2 & 3 , Table 1 )

Gymnothorax herrei (non Beebe & Tee-Van)— Randall & Golani 1995: 860 (Red Sea, description); Randall 1995: 56 ( Oman & Arabian Gulf, description); Zajonz & Khalaf 2002 ( Socotra Archipelago).

Gymnothorax pseudoherrei (non Böhlke)— Böhlke 2000: 408 (description, in part); Zajonz et al. 2019: 62 ( Socotra Archipelago, listed); Smith et al. 2019: 51 (Red Sea, description).

Holotype. SMF 34700 (tissue sample SOC18-087, corresponding to BOLD access number LIDMA3469-21 ), 205 mm TL, Yemen, Socotra Archipelago , Socotra Island, Di Hamri, a large coral block, 12°40’ N, 54°11’ E, 8–10 m, 29 April 2018, S. V. Bogorodsky & F. Saeed.

Paratypes. Red Sea : KAUMM 409 (1, 112 mm), Saudi Arabia, Farasan Archipelago, Dumsuk Island , 16°31’ N, 42°01’ E, 26 February 2012 ; KAUMM 410 (1, 116 mm, corresponding to BOLD access number GBMNB9995- 20 ), Saudi Arabia, Al Lith, 20°16’ N, 39°59’ E, 6–9 m, 18 November 2014 ; SMF 33616 (1, 107 mm), Saudi Arabia, Al Lith, 20°15’ N, 39°55’ E, 29 March 2011 ; SMF 35822 (1, 171 mm), Red Sea, Saudi Arabia, Farasan Archipelago, Dumsuk Island , 16°31’ N, 42°01’ E, 26 February 2012 ; SMF 35877 (1, 127 mm, corresponding to BOLD access number GBMNB9996-20 ), Saudi Arabia, Farasan Archipelago, Abkar Island , 16°37’ N, 41°55’ E, 6–10 m, 11 February 2017 ; USNM 312234 (8, 116–204 mm), Eritrea, Dahlak Archipelago, Sheik el Abu, 16°13’ N, 39°44’ E, 0–4.6 m, 14 August 1969 ; USNM 312247 (1, 150 mm), Eritrea, Melita Bay , 15°25’ N, 39°82’ E, 0–7 m, 13 August 1969 ; USNM 397542 (1, 179 mm), Yemen, Hanish Island , 3 m, 23 October 2009 . Socotra Archipelago: SMF 34701 (1, 185 mm), Abd al-Kuri Island, north coast, 700 m off Bir al Agooz, 12°12’ N, 52°19’ E, 8–11 m, 06 April 2000 . Arabian Gulf: BPBM 33328 (1, 291 mm), west side Jana Island , reef flat, 1.5 m, 13 September 1985 [also paratype of Gymnothorax pseudoherrei ]; BPBM 33356 (3, 208–256 mm), southeast side of Jana Island , 16.8 m, 13 September 1985 [also paratype of Gymnothorax pseudoherrei ]. Oman, Gulf of Oman : BPBM 21473 (1, 208 mm), Doha, south side of harbor of Mutrah , 1–3 m, 17 March 1977 [also paratype of Gymnothorax pseudoherrei ].

Non-types. Red Sea: HUJ 15110 (2, 185–193 mm), Eritrea, Dahlak Archipelago , Romia Island, 29 March 1962 (erroneously reported as HUJ 15113 by Smith et al. 2019) ,; USNM 312218 (1, 51 mm), Eritrea, Dahlak Archipelago , Shumma, 15°32’ N, 40°00’ E, 0–7 m, 09 August 1969 ; USNM 312233 (21, 115–215 mm), Eritrea, Dahlak Archipelago , Delemmi, 15°31’ N, 39°54’ E, 0–3 m, 07 August 1969 ; USNM 312699 (1, 85 mm), Egypt, Gulf of Aqaba , bay at El Himeira, 9–12 m, 08 September 1969 . Socotra Archipelago: SMF 34702 (4, 155–193 mm), Abd al-Kuri Island, north coast, east off Badh Issa, 12°12’ N, 52°17’ E, 5–7 m, 12 April 1999 . Oman (all from Böhlke 2000; also paratypes of Gymnothorax pseudoherrei ): BPBM 21473 (1, 208 mm), off village of Doha, south side of harbor of Mutrah, 1–3 m, 17 March 1977 ; ROM 40446 (1, 127 mm), Kalhat (Qualhat), 50 m north of tip of gravel spit at outlet of Kalhat Wadi, 200 m before start of cliffs, 22°42’ N, 59°25’ E, 23 January 1981 ; ROM 40447 (1, 247 mm), 5 miles southeast of town adjacent to second beach that breaks the line of cliffs, 22°33’ N, 59°36’ E, 04 November 1981 ; ROM 40646 (3, 51–55 mm), Kalhat , 1 mile northwest of end of wadi, 200 m before start of cliffs, 22°43’ N, 59°22’ E, 23 January 1981 .

Diagnosis. Small size, less than about 300 mm TL; dorsal-fin origin before gill opening; maxillary teeth biserial; two branchial pores; total vertebrae 114–120; body plain brown in color, with dark grooves on throat and posterior part of head; tail at tip dark yellow, becoming uniform brown in large adults.

Description (data from the holotype first, for paratypes in parentheses). In TL: preanal length 2.1 (2.0–2.4), predorsal length 9.2 (8.1–12), head length 9.0 (6.8–9.5), depth at gill opening 27 (16–27), depth at anus 20 (16–25). In HL: snout length 6.6 (5.7–6.8), eye diameter 7.9 (8.0–11), upper-jaw length 3.0 (2.7–3.6). Predorsal vertebrae 8 (5–8), preanal vertebrae 48 (42–50), total vertebrae 115 (114–120).

A relatively small, moderately stout, moray eel, to ca. 300 mm TL. Anus slightly before midlength. Dorsal-fin origin before gill opening. Snout relatively short and tapering, upper and lower jaws equal in length. Eye moderate, over middle of upper jaw. Anterior nostril tubular, moderate in length, barely reaching edge of lip when depressed. Posterior nostril broadly oval, with a low rim, above anterior half of eye.

Lateral line with two small pores (branchial pores) at anterior end of canal, above and before gill opening and behind level of dorsal-fin origin. Supraorbital canal with three pores: the first below and slightly before level of anterior nostril, about midway between base of nostril and upper jaw; the second lateral to and slightly above base of anterior nostril; the third on top of snout, slightly closer to level of anterior nostril than to eye. Infraorbital canal with four pores: the first slightly behind level of anterior nostril; the second between anterior nostril and eye, slightly closer to eye than to nostril; the third below eye, slightly behind its anterior margin; the fourth below eye, slightly before its posterior margin. Preoperculo-mandibular canal with six pores: the first and smallest near tip of lower jaw; the second slightly behind level of first; the third almost directly below level of second infraorbital pore; the fourth directly below third infraorbital pore; the fifth slightly behind level of fourth infraorbital pore; the sixth slightly behind level of rictus.

Teeth stout, sharp, and smooth, without serrations. Intermaxillary teeth curved, in a single peripheral series, with about 6–8 on each side, increasing in size posteriorly, 1–2 median teeth, relatively stout, the posterior one larger ( Fig. 2 ). Maxillary teeth biserial: about 7–14 larger, curved and more acute teeth in the inner row; 19–22 smaller and more bluntly pointed teeth in the outer row; the length of the two rows about equal. Mandibular teeth in general uniserial in adults except for 1–4 larger, conical teeth anteriorly on inner row; about 17–27 smaller, blade-like teeth on outer row. About 7–13 stout, blunt vomerine teeth, uniserial or slightly staggered.

Color (based on the holotype, Fig. 3 , and specimens reproduced in Randall (1995) and Smith et al. (2019)): larger specimens medium to dark brown, without prominent markings; head somewhat paler than body, more so ventrally. Smaller specimens with posterior one-fourth of body yellowish; yellow area diminishes with growth, becoming restricted in adults to posterior tip of tail and adjacent fins. Longitudinal dark grooves on throat and posterior part of head, present in specimens at least as small as 85 mm TL.

Size and development. Based on the specimens examined, the maximum size appears to be about 300 mm TL. The five largest specimens from the Arabian Gulf and Gulf of Oman (208–291 mm TL) are larger than any of those collected in the Red Sea (largest specimen 215 mm TL) but this may just be an artifact of collection, i.e., perhaps different collection methods. The largest specimen from the Socotra Archipelago is the holotype of 205 mm TL. As pointed out by Smith et al. (2019: 51), this species grows considerably larger than Gymnothorax pseudoherrei , with which it was initially confused—to 291 mm TL vs. 182 mm respectively. None of the specimens appeared to be ripe.

Distribution and habitat. This species has been recorded from the Red Sea, the Arabian Gulf, the Gulf of Oman, and the Socotra Archipelago at depths of 0– 17 m. It has not been reported from the coast of Yemen to central Oman, but perhaps these areas have not been sufficiently collected. The specimens show no obvious differences between localities. The species occurs in coastal coral habitats deep in crevices and is very rarely seen at night.

Etymology. Named for the area in which the species is found, the waters around the Arabian Peninsula.

Remarks. Gymnothorax arabicus and G. pseudoherrei belong to the group of morays characterized by uniform brown body color and vertebrae fewer than 150. The informal group was created by Böhlke (2000), who recognized eight species: Gymnothorax atolli ( Pietschmann, 1935) ; G. australicola Lavenberg, 1992 ; G. herrei Beebe & Tee-Van, 1933 ; G. kontodontos Böhlke, 2000 ; G microstictus Böhlke, 2000 ; G. panamensis ( Steindachner, 1876) ; G. pindae Smith, 1962; and G. pseudoherrei Böhlke, 2000 . The group was expanded to 12 species with descriptions of four species from Indian waters: Gymnothorax andamanensis Mohapatra et al., 2019 ; G. mishrai Ray et al., 2015 ; G. odishi Mohapatra et al., 2018 ; and G. tamilnaduensis Kodeeswaran et al., 2023 . Kodeeswaran et al. (2023: 259, Table 2) provided a comparison of all 12 species of the group.

Of those species, only four have vertebral counts that overlap that of Gymnothorax arabicus . Gymnothorax herrei differs in having only one branchial pore (vs. two pores) and the dorsal-fin origin over or posterior to the gill opening (vs. dorsal-fin origin anterior to gill opening). Gymnothorax microstictus has a dark and indistinctly mottled color pattern (vs. plain brown) and one row of maxillary teeth in adults (vs. two). Gymnothorax pindae has a stouter body (depth at gill opening 11–15 in TL vs. 16–27), greater head length (5.0–7.0 in TL vs. 6.8–9.5), grows to a larger size (to 450 mm TL vs. 300 mm), and the maxillary teeth are either uniserial or, when biserial (young specimens), the inner row is shorter than the outer row (vs. biserial with inner row as long as outer). Gymnothorax pseudoherrei is discussed separately below.

Figures

FIGURE 2. Dentition pattern on upper jaw and lower jaw of Gymnothorax arabicus sp. nov. (SMF 34701, paratype). Drawing by U. Zajonz.

FIGURE 3. Gymnothorax arabicus sp. nov., freshly collected specimen, SMF 34700 (sample tissue SOC18-087), holotype, 205 mm TL, Di Hamri, Socotra Island, Socotra Archipelago. A: whole moray; B: head close-up. Photos by S.V. Bogorodsky.