Mulloidichthys flavolineatus flavicaudus (n = 29)

Paratypes (n = 5): CAS 237352, 4: 107-147 mm SL, and BPBM 41246, 102 mm SL, Red Sea, Saudi Arabia, Thuwal, 22°13’50”N, 39°01’43”E.

Non-types (n = 24). Red Sea: Israel, Gulf of Aqaba, Eilat: CAS 58876, 252 mm SL; CAS 206559, 146 mm SL; CAS 206715, 133 mm SL; CAS 206726, 198 mm SL; CAS 206736, 167 mm SL; SAIAB 4146 and 4160, 2, 126-152 mm SL, 29°33’S, 34°57’E; SAIAB 65788, 3, 91-100 mm SL, north beach; Egypt, Gulf of Suez: MNHN 1980-1504, 2, 194-203 mm SL; N Red Sea, possibly Egypt: MNHN 1980- 1501, 177 mm SL, unknown locality “Kaded el hamden” (coll. Dollfus); MNHN 1980-1502, 159 mm SL, unknown locality “El had yayah” (coll. Dollfus); possibly Egypt or northern Sudan: MNHN A.3515, 2, 171-196 mm SL (coll. Botta); Sudan: HIFIRE 58445, 5, 148-181 mm SL and HIFIRE 58446, 181 mm SL, Port Sudan, fish market; Saudi Arabia: RMNH 25004, 82 mm, Jeddah; Eritrea: MNHN A. 3514, 136 mm SL, Massawa, 15°37’1”N, 39°28’1”E.

Diagnosis

First dorsal fin VIII, the first minute spine sometimes considerably reduced and/or hidden below skin and hence difficult to detect; pectoral fins 15-18; gill rakers 7-10 + 18-22 = 25-31; lateral-line scales 33-38; morphometric characters in adult fish (≥ 90 mm SL): body depth at first dorsal-fin origin 21–26; body depth at anus 16-22; caudal-peduncle depth 7.9-9.7; caudal-peduncle width 2.7-4.6; maximum head depth 18-22; head depth through eye 15-19; head length 27-33; snout length 12-16; orbit length 5.6-9.0; upper jaw length 8.2-10; barbel length 18-23; caudal-fin length 28-33; anal-fin height 12-16; pelvic-fin length 18-23; pectoral-fin length 18-23; pectoral-fin width 3.6-5.3; first dorsal-fin height 18-25; second dorsal-fin height 12-16; body silvery white, sometimes infused with yellow, darker above lateral line; head silvery white to yellowish, darker on dorsal part of snout and dorsally from mid-orbit; one straight yellow mid-lateral body stripe, its width subequal to pupil diameter frequently with a dark oval to rectangular blotch on yellow mid-lateral body stripe below first dorsal-fin base; stripe and/ or blotch sometimes only faintly or not visible due to colour changes, blotch often retained in preserved fish; dorsal and caudal fins whitish-grey or yellowish, pectoral, pelvic and anal fins pale whitish-grey or rose, partly transparent; barbels white; in preserved fish body generally pale brown to brown or ventrally pale and dorsally darkened; head pale brown to brown; fins uniformly pale-brown, partly hyaline.

Morphometric characters in juvenile fish (<90 mm SL): body depth at first dorsal-fin origin 19-23; body depth at anus 15-20; caudal-peduncle depth 7.7-9.0; caudal-peduncle width 2.7-3.8; maximum head depth 17-20; head depth through eye 13-17; head length 26-30; snout length 8.6-12; orbit length 6.6-9.0; upper jaw length 7.6-8.9; barbel length 14-21; caudal-fin length 26-31; anal-fin height 13-16; pelvic-fin length 19-23; pectoral-fin length 16-21; pectoral-fin width 3.4-4.2; first dorsal-fin height 18-22; second dorsal-fin height 13-15.

Meristic characters in subspecies: Mulloidichthys f. flavicaudus: First dorsal fin VIII, the first minute spine well detectable in 25% of adults; pectoral fins 15-17; gill rakers 7-9 + 18-20 = 25-29; lateral-line scales 33-35; M. f. flavolineatus: First dorsal fin VIII, the first minute spine well detectable in over 50% of adults; pectoral fins 15-18; gill rakers 7-10 + 19-22 = 26-31; lateral-line scales 34-38.

Distribution, size, depth and habitat

Mulloidichthys flavolineatus occurs in the Indian Ocean to Central Pacific: Red Sea, East and South Africa, Madagascar and Mascarenes east to the Hawaiian Islands, Line Islands and Pitcairn Group, north to southern Japan and Midway Islands, south to North West Cape (Western Australia), New South Wales (Eastern Australia) at 36°S, Lord Howe Island, and New Caledonia, a single record from New Zealand (RMNH.PISC.11308). It attains at least 34 cm SL and occurs from close to the surface to 99 m depth, on or slightly above soft or hard bottoms, often on or in the vicinity of coral reefs.

Interspecific comparisons and differential diagnoses

Adult Mulloidichthys flavolineatus differs from all other congeners in a shallower body (e.g. body depth at dorsal-fin origin 21-26 vs. 25-30% SL; body depth at anal-fin origin 16-22 vs. 21-27% SL) and the frequent presence of a dark oval or rectangular blotch at mid-body below the first dorsal-fin base; in addition, it differs from M. ayliffe and M. mimicus in a shallower caudal peduncle (7.9-9.7 vs. 10-11% SL) and a single yellow vs. several yellow and bluish lateral body stripes; it differs from M. pfluegeri in fewer lateral line scales (mostly 33-37 vs. 38-39), in a narrower caudal peduncle (2.7-4.6 vs. 4.6-6.0% SL), shallower suborbital (8.0-12 vs. 12-14% SL), shorter jaws (upper-jaw length 8.2-10 vs. 11-12% SL), narrower pectoral fin (3.6-5.3 vs. 5.4-5.7% SL) and the presence of mid-lateral body stripe vs. absence; and it differs from M. vanicolensis in fewer gill rakers (gill rakers on lower limb 18-22 vs. 23-26; total gill rakers 25-31 vs. 31-35).

Juvenile M. flavolineatus differs from M. mimicus (a single 79 mm SL specimen examined by Uiblein, 2011) in a shallower body (e.g. body depth at dorsal-fin origin 19-23 vs. 24% SL; body depth at anal-fin origin 15-20 vs. 22% SL), shallower caudal peduncle (7.7-9.0 vs. 9.4% SL), longer upper jaw (7.6-8.9 vs. 9.3% SL), wider interdorsal distance (13-17 vs. 12% SL), shorter second dorsal-fin base (11-13 vs. 16% SL), shallower anal fin (13-16 vs. 17% SL), and shallower dorsal fins (first dorsal fin height 18-22 vs. 23% SL; second dorsal-fin height 13-15 vs. 16% SL). No other comparative data for juveniles of Mulloidichthys species are currently available.