Acanthopagrus catenula ( Lacepède 1801 ), Lacepede, 1801

Iwatsuki, Yukio & Heemstra, Phillip C., 2011, 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), Zootaxa 3025, pp. 38-50 : 45-48

Acanthopagrus catenula ( Lacepède 1801)

New English name: Bridled Seabream Figs. 1B, 2B, 3E‒H, 4C‒D & 5B

Labrus catenula Lacepède 1801:426 , 468, plate 3, figure 3 (type locality: Mauritius). Sparus mylio Lacepède 1802:41 , 131 (type locality: Mauritius).

Holotype. MNHN A- 0961, dried, 171 mm SL, Mauritius.

Non-type specimens (19 specimens, 101‒364 mm SL). BPBM 27366, 166 mm SL, Natal, South Africa; MNHN A- 4149, 2: 101‒104 mm SL, Madagascar; MNHN 1981-0812, 114 mm SL, Madagascar; MUFS 25806‒25808, 3: 266‒364 mm SL, off Socotra Island, Somalia, trawls: MUFS 33573–33575, 3: 231‒255 mm SL, Madrakah, southern Oman 6 Oct., 2010, hand-line; SAIAB 9672, 139 mm SL, Kosi Bay, KwaZulu-Natal, South Africa; SAIAB 11819, 153 mm SL, Malindi, Kenya; SAIAB 11820, 167 mm SL, Mozambique; SAIAB 11821, 141 mm SL, South Africa; USNM 29538, 4: 280‒330 mm SL, north coast of Somalia, southeasternmost part of Gulf of Aden (11º54'06"N, 51º03'12"E), trawls.

Diagnosis. Distinguished from other species of Acanthopagrus by the following combination of characters: two conspicuous vertical black bars across the head (Figs. 1–3); dorsal fin with wide black margin, especially distinct in distal spinous part of dorsal fin in fish <ca. 30‒36 cm SL ( Fig. 2 B, 3E‒H), proximal part of dorsal fin yellow; hind margin of caudal fin with narrow black edge in fish to around 30 cm SL, and then disappearing with growth ( Fig. 2 B, 3E‒H); scale rows between fifth dorsal-fin spine and lateral line 4 ½; third outer molar teeth row extending to rear end of both jaws; ( Fig. 4 B), basal width of 6 enlarged incisor teeth at front of upper jaw larger, 1.0‒1.1 mm for 16 cm SL fish, and 5.0‒5.5 mm for 34 cm SL fish ( Fig. 5 B); dorsal-fin rays XI, 12‒14; anal-fin rays III, 10; orbit diameter ( Fig. 6 ), noticeably larger in fish> 15 cm SL.

Description. Counts and measurements of the holotype and 20 non-type specimens of Acanthopagrus catenula are given in Table 1 . Body deep, compressed; mouth somewhat oblique, lips thick; maxilla reaching to vertical below middle of pupil in young and to vertical at rear edge of pupil in fish over 25 cm SL ( Fig. 3 E & F); lower jaw slightly included, especially in fish larger than 35 cm SL; upper jaw usually with 6 distinct incisor-like teeth in juveniles, becoming curved canines in adults; front of lower jaw with 6 canines ( Fig. 5 C & D) but 4 middle canines becoming considerably larger than outer teeth in adults ( Fig. 6 C & D); upper jaw generally with 6 molar tooth rows anteriorly, 4 rows of larger molar teeth posteriorly, innermost teeth smallest, but outermost teeth at mid-jaw also well-developed; lower jaw with 4 molar tooth rows, teeth small anteriorly, increasing in size and forming 3 rows posteriorly; least infraorbital depth less than eye diameter in juveniles and greater than orbital diameter in adults> 30 cm SL; cheek scales in 4 or 5 transverse rows; occipital profile weakly curved, somewhat gibbous head above eye in specimens> 30 cm SL ( Fig. 3 H); 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 less than first anal-fin ray; pectoral fins longer than head, tip reaching beyond vertical at second or third anal-fin spine base in fish <20 cm SL, pelvic fin clearly shorter than head; pelvic-fin spine longer than snout.

Colour of fresh specimens. Based on specimens from South Africa, off Socotra Island, Somalia, and Rodrigues (not kept, ca. 30 cm TL, photographed by T. Hooper and MUFS 25806‒25808, 266‒ 364 mm SL, Fig. 4 H for MUFS 25808). Head and body silvery, sometimes with a black spot at center of each scale (spots more distinct in live specimens or some specimens from off the Horn of Africa, Somalia) forming dotted lines following scale rows parallel to lateral line above lateral line, and also (faintly) below lateral line ( Fig. 3 G & H); snout and infraorbital area yellow, especially in fish> 20 cm SL ( Fig. 3 H); dorsal, caudal and pectoral fins yellow in young and vivid yellow in specimens over 20 cm SL; dorsal fin with a wide black margin; caudal fin with a narrow black edge but diappearing with growth in specimens> ~ 30 cm SL; pectoral fins often black with a yellow base; juveniles with hyaline yellow pectoral fin, becoming vivid yellow at base on fish> 20 cm SL ( Fig. 2 B, 3G & H); pelvic- and analfin rays dense black; posterior part of anal fin often hyaline in juveniles and presumably first maturity size, 25 cm SL; Fig. 2 B, 3G), and becoming black in larger adults over 35 cm SL; Fig. 3 H).

Colour of preserved specimens. Head and body pale yellowish tan, yellow of dorsal and caudal fins faded, but black margin of dorsal-fin and black rear edge of caudal fin usually remain, caudal fin dark edge disappearing in largest specimen ( MUFS 25808, 364 mm SL; Fig. 3 H); faint dotted lines along scale rows often remain but disappears in old specimens; black of pelvic and anal-fin rays and the two conspicuous black bars on head become fainter ( Fig. 3 E & F).

Distribution. Acanthopagrus catenula is currently known from off the Horn of Africa to off Socotra Island of Somalia, including Kenya, Mozambique, South Africa, Madagascar, Mauritius, and Rodriguez. Recently, A. catenula was collected in Madrakah, southern Oman (MUFS 33573–33575, 3 specimens, 231‒255 mm SL, 6 Oct., 2010) during the first author’s visit.

Remarks. Lacepède (1801) described Labrus catenula on the basis of a holotype (MNHN A-0961, dried, 171 mm SL) from Mauritius. The dark posterior edge of the caudal fin in the dried holotype is still clearly visible as are the counts of 4 ½ scale rows between the fifth dorsal-fin spine and lateral line, being diagnostic characters of this species. Unfortunately, the black margin of the dorsal fin was not visible because no dorsal-fin membrane remains on this dried specimen (Fig. 1B).

Figures

FIGURE 2. Colour photographs of A Acanthopagrus bifasciatus and B A. catenula. A A. bifasciatus, BPBM 18173, 151 mm SL, Ras Muhammad, Sinai Peninsula, Egypt, Red Sea; B, SAIAB 9672, 139 mm SL, Kosi Bay, KwaZulu-Natal, South Africa.

FIGURE 3. Stages of A ‒ D Acanthopagrus bifasciatus and E ‒ H A. catenula. A, SMF 24659, 101 mm SL, Red Sea; B, BPBM 18173, 151 mm SL, Ras Muhammed, Sinai Peninsula, Egypt; C, BPBM 29526, 238 mm SL, Bahrain; D, MUFS 25811, 362 mm SL, off southern Oman facing Indian Ocean; E, MNHN A 4149, 103 mm SL, Madagascar; F, SAIAB 11819, 153 mm SL, Kenya; G, Uncatalogued specimen (reversed), ca. 30 cm TL, Rodrigues, photographed by T. Hooper; H, MUFS 25808, 364 mm SL, off Socotra Island, Somalia.

FIGURE 4. Teeth of upper and lower jaws of A ‒ B Acanthopagrus bifasciatus and C ‒ D A. catenula. A ‒ B, BPBM 18173, 151 mm SL, Red Sea; C ‒ D, SAIAB 11820, 162 mm SL, South Africa.

FIGURE 5. Clear different sizes of upper teeth on the same size specimens of A Acanthopagrus bifasciatus and B A. catenula. A, MUFS 25810, 335 mm SL, Oman; B, MUFS 25807, 345 mm SL, off Socotra Island, Somalia.

FIGURE 6. Orbit diameters of Acanthopagrus bifasciatus (open circle) and A. catenula (solid triangle) in relation to standard length.