A review of the Acanthopagrus bifasciatus species complex (Pisces: Sparidae) from the Indian Ocean, with redescriptions of A. bifasciatus (Forsskål 1775) and A. catenula (Lacepède 1801) Author Iwatsuki, Yukio Author Heemstra, Phillip C. text Zootaxa 2011 3025 38 50 journal article 46354 10.5281/zenodo.205951 9282e4a5-1c49-4350-a14a-99efaa23dac1 1175-5326 205951 Acanthopagrus bifasciatus ( Forsskål 1775 ) English name: Doublebar Seabream Figs. 1A, 2A, 3A‒D, 4A‒ B & 5A Chaetodon bifasciatus Forsskål 1775 :64 , xiii ( type locality: Jidda, Saudi Arabia , Red Sea). Holocentrus rabaji Lacepède 1802 :724 , 725 ( type locality: Red Sea). Chysophrys bifasciatus ; Valenciennes 1830:118 (in part; distribution is that of both Acanthopagrus bifasciatus and A. catenula ). Sparus bifasciatus ; Fowler 1933 :160 (includes Sparus mylio and Labrus catenula ). Holotype . ZMUC-P 50557, dried, 111 mm SL , Jidda, Saudi Arabia , Red Sea. Non-type specimens ( 37 specimens : 27‒362 mm SL ). BPBM 18173, 2: 158174 mm SL , Ras Muhammad, Sinai Peninsula, Egypt , Red Sea; BPBM 21294, 207 mm SL , Bahrain ; BPBM 29526, 237 mm SL , Bahrain ; MNHN 0000-0675, 145 mm SL , Eritrea (formerly Ethiopia ), Red Sea; MNHN 0000-8614, 2: 89‒121 mm SL , Red Sea; MNHN 1902-0161, 161 mm SL , Persian Gulf; MNHN 1966-0090, 147 mm SL , Red Sea; MNHN 1977-0953, 6: 28‒44 mm SL , Israel ; MUFS 25809‒25811, 3: 285‒362 mm SL , off southern Oman facing Indian Ocean, not Gulf of Oman ; SMF 2196, 116 mm SL , Red Sea; SMF 21504 , 47 mm SL , Persian Gulf; SMF 21750 , 94 mm SL , Red Sea; SMF 24659 , 101 mm SL , Red Sea; USNM 19168, 12: 37‒75 mm SL , Red Sea; USNM 266730, 93 mm SL , Bahrain , Persian Gulf; USNM 374204, 2: 102‒118 mm SL , Eritrea ( Ethiopia ), Red Sea. Diagnosis. Distinguished from other species of Acanthopagrus by the following combination of characters: two conspicuous vertical black bars across the head, the first bar from occiput through eye and across cheek to rear end of maxilla, the second bar from nape to opercle (Figs. 13); dorsal and caudal fins yellow, without dense black margin of dorsal-fin or narrow black edge along rear margin of caudal fin ( Fig. 2 A, 3A‒D); 5 ½ or 6 ½ scale rows from 5th dorsal fin spine to lateral line; base of dorsal and anal fins scaly; interorbital area and preopercle flange naked; 2 rows of molars along each side of upper jaw; outer molar teeth row extends to rear end of both jaws ( Fig. 4 A); basal width of incisor teeth (usually 6) at front of upper jaw smaller, 0.7‒0.8 mm for 15 cm SL fish and 2.2‒2.5 mm for fish of 34 cm SL, respectively; Fig. 5 A); dorsal-fin rays XI,12‒15; no spines elongated; anal-fin rays III,10‒11; 2nd and 3rd anal-fin spines subequal, not enlarged. Description. Counts and measurements of the holotype and 37 non-type specimens of Acanthopagrus bifasciatus are given in Table 1 . Body deep, compressed; mouth somewhat oblique, lips thick; maxilla reaching to vertical at middle of pupil; lower jaw slightly included; front of upper jaw with (usually) 6 incisors (young) that develop into curved canines in adults ( Fig. 4 AB) but the 4 middle canines (of 6) generally become larger than the outer ones ( Fig. 4 AB, 5A); molar teeth of upper jaw in 6 rows on each side of jaw anteriorly, 4 rows of larger teeth posteriorly, innermost teeth smallest, but outer teeth at mid-jaw also well-developed; lower jaw with 4 molar tooth rows on each side, teeth small anteriorly, increasing in size posteriorly and forming 3 rows on each side posteriorly ( Fig. 4 AB); least infraorbital depth less than eye diameter in young, but greater than eye diameter in fish> 30 cm SL ( Fig. 3 A); 5 or 6 transverse rows of scales on cheek; occipital profile weakly curved; dorsal-fin spines strong, heteracanthous, first spine slightly more than half length of second, second clearly shorter than third; fourth spine longest; first dorsal-fin ray shorter than longest spine; first anal-fin spine short, much less than eye diameter; second spine longest, but clearly less than head length; third anal-fin spine shorter than second spine or first anal-fin ray; pectoral-fins longer than head, their tip reaching beyond vertical at first or second anal-fin spine base; pelvic fins clearly shorter than head; pelvic-fin spine longer than snout. 1. Holotypes of A Acanthopagrus bifasciatus and B A. catenula . A , ZMUC-P. 50557, 111 mm SL, Jeddah, Saudi Arabia , Red Sea; B , MNHN A-0961, 171 mm SL, Mauritius . Colour of fresh specimens. Based on specimens from Red Sea ( Egypt ), Kuwait , Bahrain , Persian Gulf, and off southern Oman ( BPBM 18173, Fig. 2 A, and BPBM 29526, Fig. 3 C, photographed by J. E. Randall; MUFS 25809‒25811, Fig. 3 D for MUFS 25811). Head and body silvery, with a black spot at center of each body scale (especially distinct in live adult specimens or in Persian Gulf specimens), forming parallel lines following scale rows above and below lateral line; side of snout and cheek below eye yellow, more prominent in fish> 20 cm SL ; dorsal, caudal and pectoral fins yellow in young and vivid yellow in fish> 20 cm SL ; dorsal part of dorsal and pectoral fins often denser yellow than lower part, which is more hyaline yellow ( Fig. 2 A, 3C & D); yellow patch before eyes often present ( Fig. 3 C); anterior snout region often dark brown or black ( Fig. 3 C); pelvic- and anal-fin rays dense black, rear part of anal fin often transparent in fish less than 20 cm SL ( Fig. 2 A, 3A & B) and sometimes yellow in fish of 20‒30 cm SL ( Fig. 3 C) but dense black in 35 cm SL-specimen ( Fig. 3 D). TABLE 1. Counts and morphometric data for the synonymized type specimens of Acanthopagrus bifasciatus (Forsskål 1775) and A. catenula (LaCɵpòđɵ ₁⁸O₁), expressed as percentages of standard length (means in parentheses).

Acanthopagrus bifasciatus	Acanthopagrus catenula
Standard length (mm, SL)	Chaetodon bifascia- Non-type tus Holotype* specimens ZMUC P. 50557 n =1 n =37 111 mm SL 27‒362 mm SL	Labrus catenula Non-type Holotype** specimens*** MNHN A-0691 n =1 n =19+4*** 171 mm SL 101‒364 mm SL
Counts:
Dorsal-fin rays	XI, - XI, 12	XI, 13 XI‒XII, 12‒14
Anal-fin rays	III III, 10‒11	III, 10 III, 10
Pelvic and pectoral-fin rays	- I, 5; 14‒15	- I, 5; 14‒15
Pored lateral-line scales	48 47‒51	45 45‒49
Scales above and below lateral line	- / 12 5 ½‒6 ½ / 10‒14	5 ½ / 13 4 ½‒5 ½ / 11‒14
Scales between 5th dorsal-fin spine base and lateral line	5 ½ 5 ½‒6 ½	4 ½ 4 ½
Scales between 5th dorsal-fin spine base and lateral line
Gill rakers	- 6‒8+10‒13=16‒20	- 6‒7+9‒12=16‒20
Measurements: Body depth	45 38‒51 (46)	51 48‒53 (50)
Body depth at anal fin	44 33‒43 (38)	41 40‒42 (41)
Head length	30 32‒40 (36)	31 31‒38 (34)
Body width Snout length Orbit diameter	- 11‒20 (15) 11 g9‒16 (12) g6 / 7‒16 (13)	- 13‒20 (16) g6 12‒18 (14) 12 9‒14 (11)
Dermal eye opening	g4 6‒15 (11)	- 77‒11 (9)
Interorbital width Interorbital width with membrane Upper jaw length	- g8‒13 (9) - g9‒13 (11) 12 13‒17 (15)	- 10‒13 (11) - 11‒12 (11) 11 13‒16 (15)
Caudal peduncle depth	13 11‒14 (13)	15 12‒15 (13)
Caudal peduncle length Predosal length Preanal length	19 14‒21 (18) 42 42‒50 (46) 72 63‒73 (69)	19 17‒20 (18) 42 44‒51 (47) 63 66‒72 (69)
Prepelvic length	- 37‒47 (40)	40 37‒41 (39)
Dorsal-fin base length Anal-fin base length Caudal-fin length	56 47‒62 (55) 17 16‒27 (20) - 27‒33 (30)	62 54‒63 (60) 21 16‒22 (19) 30 26‒34 (31)
Pelvic-fin spine length	- 14‒25 (17)	18 14‒19 (17)
First pelvic-fin ray length Pectoral-fin length	- 20‒29 (25) - 32‒44 (38)	26 23‒27 (25) - 38‒44 (42) continued next page

TABLE 1. (continued)

Acanthopagrus bifasciatus	Acanthopagrus catenula
Standard length (mm, SL)	Chaetodon bifascia- Non-type tus Holotype* specimens ZMUC P. 50557 n =1 n =37 111 mm SL 27‒362 mm SL	Labrus catenula Non-type Holotype** specimens*** MNHN A-0691 n =1 n =19+4*** 171 mm SL 101‒364 mm SL
First dorsal-fin spine length	g6 g4‒9 (7)	g7 4‒8 (6)
Second dorsal-fin spine length	g9 g9‒19 (13)	11 8‒16 (12)
Third dorsal-fin spine length	13 13‒20 (17)	- 13‒18 (16)
Fourth dorsal-fin spine length	13 14‒21 (18)	- 11‒19 (15)
Fifth dorsal-fin spine length	12 13‒20 (17)	- 14‒17 (16)
Sixth dorsal-fin spine length	12 13‒20 (17)	- 8‒16 (14)
Last dorsal-fin spine length	g9 9‒16 (12)	- 8‒14 (11)
First anal-fin spine length	g6 33‒8 (6)	g3 4‒7 (6)
Second anal-fin spine length	18 13‒23 (19)	18 13‒22 (19)
Third anal-fin spine length	12 11‒18 (15)	15 11‒18 (16)
First anal-fin ray length	- 11‒19 (16)	14 12‒20 (17)
Least infraorbital depth	g4 g2‒7 (4)	- g4‒9 (5)

*, Dried right skin; **, Dired left skin; ***, Four specimens ( USNM 29538, 4, specimens, 280‒330 mm SL , off the Horn of Africa, Somalia ) of A. catenula were measured only for standard length and counts of scale rows between the fifth dorsal-fin spine base and lateral line. Hyphen shows no measurement as ‘-’. According to Randall (1995) , Red Sea individuals of Acanthopagrus bifasciatus ( Fig. 2 A) differ from Oman and Persian Gulf fish in lacking the rows of black spots, one per scale, on the body. However, this colour character was not always consistent (Fig. A [Red Sea but exact locality unknown showing visible spots], Fig. 3 B [Sinai Peninsula, northern Red Sea, no clear spots] and Fig. C [ Bahrain , Persian Gulf fish showing distinct spots]). Furthermore, large A. bifasciatus from southern Oman’s Arabian Sea (facing the Indian Ocean) lacked distinct dark spots ( MUFS 25809‒25811, 3 specimens, 285‒362 mm SL ). Thus it appears that the rows of dark spots become fainter with growth and more distinct if the fish is stressed. Colour of preserved specimens. Head and body pale yellowish tan, yellow or vivid yellow coloration of dorsal and caudal fins faded; dark dotted lines following scale rows often visible; pelvic and anal-fin rays dense black as well as two conspicuous bars on head ( Fig. 3 A & B). Distribution. Acanthopagrus bifasciatus is confirmed from the Red Sea ( Israel , Egypt , Eritrea [formerly Ethiopia ], and Saudi Arabia ), Persian Gulf ( Bahrain and Kuwait ), and off southern Oman (not Gulf of Oman ). The species presumably occurs along the whole southern coast of the Arabian Peninsula and is also found from Iran to Pakistan (fig. 5, Day 1875 , plate 34, figure 5, based on Sind [= Pakistan ]; Blegvad 1944 ). Remarks. Chaetodon bifasciatus was described from a specimen (Fig. 1A) from Jeddah, Saudi Arabia , Red Sea by Forsskål (1775) . Lacepède (1802) described Holocentrus rabaji as a new name for C. bifasciatus , which he apparently considered unacceptable. We consider that the species is not likely to occur in India , but it is known from Sind, Pakistan ( Day 1875 ), which is the easternmost (known) distribution. Furthermore, A. bifasciatus is found in southern Yemen and Djibouti , but the specimens from the northern Somalian coast within the Gulf of Aden may actually be A. catenula . Consequently identification of A. bifasciatus from Somalia should be re-examined. In addition, Acanthopagrus bifasciatus (first females’ maturity size, mean 26.4 cm in fork length) in the southern Persian Gulf ( UAE ) spawns in January ( Grandcourt et al . 2004 ), which is also a monsoon season when primary production in the Persian Gulf is high ( Hirawake et al . 1998 ).