Echidna polyzona (Richardson 1845) —Barred Moray

(Figure 4)

Muraena polyzona Richardson 1845: 112, pl. 55 (figs. 11–14) (No locality). Lectotype, BMNH 1977.4.22.3, designated by Böhlke & Randall 2000: 220.— Klunzinger 1871: 617.

Echidna polyzona: Marshall 1952: 223; Goren & Dor 1994: 7; Randall & Golani 1995: 851; Khalaf 2004: 35; Golani & Bogorodsky 2010: 9; Golani & Fricke 2018: 20.

Red Sea material. Israel: BPBM 35748 (1, 173), Eilat; HUJ 5243 (1, 435), Eilat. Egypt: HUJ 15093 (3, 110–128), Nabq; USNM 312209 (2, 66.5–143), Marsa Muqabila. Eritrea: USNM 312158 (1, 364).

Comparative material. Mauritius: USNM 342100 (3, 94–ca 290). Solomon Is.: USNM 385375 (3, 5 7–185). Vanuatu: USNM 362155. French Polynesia, Tahiti: USNM 66087 (1, 242); USNM 312154 (1, 182). Hawaii: USNM 89537 (1, 193); USNM 109332 (2, 75–272).

Description. In TL: preanal length 2.1–2.2, predorsal length 8.1–9.1, head 6.8–7.8, body depth at anus 13–22. In head length: snout length 5.6–7.0, eye diameter 6.6–10, upper-jaw length 2.7–3.4. Pores: LL 2, SO 3, IO 4, POM 6. Vertebrae: predorsal 4–6, preanal 50–52, total 119–125.

Body moderately stout; anus near midlength; dorsal fin begins slightly anterior to gill opening; anal fin begins immediately behind anus. Head moderate in length, snout relatively short and deep. Eye moderately small, closer to rictus than to snout tip. Rim of posterior nostril slightly raised, edge fimbriated.

Teeth stout, bluntly pointed to molariform, somewhat variable in number and arrangement, generally more numerous in larger specimens. Intermaxillary with a peripheral series of ca. 4–7 on each side; sometimes an intermediate series of 2–3 on each side; 1–3 median teeth. Maxillary teeth biserial; 3–7 larger teeth in inner row, 4–12 smaller teeth in outer row. Dentary teeth biserial, those in inner row larger, ca. 11–13 in adults, fewer in juveniles; ca. 12–20 in outer row. Vomerine teeth large, molariform, in an elliptical, multiserial patch, narrowest at anterior and posterior ends, biserial in smaller specimens, up to 5–6 teeth across in larger ones.

Color: variable, changing considerably with growth. Typical pattern ca. 25 contrasting alternating broad dark brown and narrow white bars on head and body and extending onto dorsal fin; bars best developed in smaller adults, white bars becoming progressively more obscure with growth; body becoming mottled with brown overall and the bars less distinct, visible only on tail with further growth. Corner of mouth dark; anterior nostrils brownish yellow.

Maximum size about 600 mm.

Distribution and habitat. Found across the Indo-West Pacific from the Indian Ocean to Hawaiian Islands and French Polynesia. Occurs in shallow water, common on coral reefs, sometimes found on reef flats; observed from depths of 3– 15 m.

Remarks. This species shows little morphological variation over its range. Three Red Sea specimens have slightly fewer vertebrae (117–122) than 14 specimens from elsewhere (119–125). Similar slight differences occur in predorsal vertebrae (4–5 vs. 5–7) and preanal vertebrae (49 vs. 50–52).

The species superficially resembles Gymnothorax rueppelliae, but the dentition is very different. In addition, the snout is longer in G. rueppelliae, and the bars on the head do not extend onto the lower jaw.

The variation in color pattern and dentition over the life cycle of this species has resulted in 11 synonyms, seven of them from the Hawaiian Islands alone.

In the COI-based phylogeny, E. polyzona was very close to E. leucotaenia Schultz with no strong genetic divergence between them, which is in agreement with the multigene analysis in Reece et al. (2010), from which COI sequences of both species were used herein as no specimens of this species were collected during the present study. As in the aforementioned multigene analysis, no close allies of these two species could be identified from the phylogenetic tree (see Fig. 48).