Acanthopagrus randalli, Iwatsuki, Yukio & Carpenter, Kent E., 2009

Iwatsuki, Yukio & Carpenter, Kent E., 2009, Acanthopagrus randalli (Perciformes: Sparidae), a new black seabream from the Persian Gulf, Zootaxa 2267, pp. 43-54 : 44-50

Acanthopagrus randalli n. sp.

New English Name: Middle East Black Seabream ( Figure 1 ; Table 1 )

Holotype: BPBM 33135, 322 mm, off Bahrain (collected from fish market in Bahrain), 13 November 1983, Persian Gulf, purchased by J. E. Randall.

Paratype: MTUF-P 27226, 173 mm SL, off Kuwait (collected from Central Fish Market, Kuwait City), Persian Gulf, 29 December 1994, purchased by M. Moteki.

Diagnosis: Dorsal-fin rays XI, 11; anal-fin rays III, 8; 4 ½ scale rows between fifth dorsal-fin spine base and lateral line; 5 ½ scale rows above lateral line and 11 ½ or 12 ½ scale rows below; pored lateral-line scales 46; eyes of larger type distinctly separated from dorsal head profile because of a prominent convexity from snout to just above eye that becomes more convex with growth, both interorbital bulge span and interorbital width greater than orbit diameter (interorbital bulge span / orbit diameter 1.56–2.03, mean 1.80; inɭɵrΟrbiɭaI wiđɭh / Οrbiɭ điamɵɭɵr 1.43–1.71, mean 1.57); four or five wide vertical bands (six or seven horizontal scale rows in width) on body, presumably clearer in agitated or stressed live specimens ( Fig. 1 A-B, bands not clear on figure of holotype but four bands are evident on specimen, particularly when viewed from above and four clear bands and one faint band in a smaller specimen of paratype), first bar from nape to around upper pectoral-fin base, second bar from dorsal-fin base between fourth and seventh dorsal-fin spine, through lateral line, to abdomen, third bar from base between ninth dorsal-fin spine and first dorsal-fin ray, through lateral line, to just before first anal-fin spine origin, fourth bar from dorsal-fin base between fifth dorsal-fin ray and last dorsal-fin ray, plus a faint bar on caudal peduncle that is darker dorsally; conspicuous diffuse dark blotch at origin of lateral line (covering first and second pored lateral line scales) continuous with a dense blackish shading over upper cleithrum and upper posterior opercle; anal-fin membrane nearly hyaline in smaller type and in larger type membrane is hyaline with sparse black melanophores that are lacking on membranes of the posteriormost rays; posterior margin of caudal fin darker than rest of fin.

Description: Counts and measurements of a holotype and a paratype are given as percentages of SL in Table 1 . Data for the holotype is presented first, followed in parenthesis by paratype data if different and available. Characters stated in the diagnosis are not repeated.

Body compressed; mouth somewhat oblique; maxillary reaching to below middle of pupil and lager than eye diameter; lower jaw included in upper jaw; teeth in jaws in 3 to 5 rows, anteriorly about 6 (or 7) curved canines in the upper jaw and 6 in the lower jaw; upper and lower molar teeth strongly developed, subequal in size except some progressively larger posteriorly and some progressively smaller anteriorly and posteriorly, in upper jaw up to 5 rows and lower jaw up to 4 rows; suborbital depth slightly shorter than dermal eye opening (clearly shorter than dermal eye opening); 5 (or 6) irregular transverse rows of scales on preoperculum; anterodorsal profile from just above eye ascending gently and curved; anteriormost margin of head scalation rounded when viewed from above, reaching to just beyond posteriormost margin of orbit and without small scales anterior to scalation margin; dorsal-fin spines strong, first slightly longer than half length of second spine, which is shorter than third spine; fourth or fifth spine longest; longest soft dorsal-fin ray shorter than longest spine in dorsal fin; first anal-fin spine short, its length much less than eye, robust, not flattened; second anal-fin spine length clearly less than head without snout; third anal-fin spine shorter than second spine, which is slightly longer than snout; first anal-fin ray subequal to second anal-fin spine and slightly longer than third spine; pectoral-fin tip nearly reaching to first anal-fin spine base vertically, its length clearly greater than head length; longest pelvic-fin ray clearly less than head; pelvic-fin spine longer than snout.

Colour when fresh: Colour when fresh is based on a colour photograph by J. E. Randall of the holotype after death: head and body silvery grey and both ventral part of head and abdomen somewhat white; dorsal, caudal, anal and pectoral fins a slight blackish-gray.

Colour in preservation: Head and body yellowish tan; both ventral part of head and abdomen whitish; dorsal, caudal, anal, pelvic and pectoral fins slight yellowish hyaline.

Distribution: Acanthopagrus randalli is currently known only from and apparently endemic to the Persian Gulf.

Etymology: The specific name “ randalli ” is proposed in honor of Dr. John E. Randall who collected the holotype and who is clearly one of the greatest ichthyologists of all times.

TABLE 1 .

Acanthopagrus randalli n. sp. Remarks: As noted in the introduction, the 11 species of Acanthopagrus and Sparidentex can be divided into six morphological forms. Acanthopagrus randalli belongs to the Blackfin Seabream Form I with 3 ½ or 4 ½ scale rows between the fifth dorsal-fin spine base and lateral line that also includes A. akazakii , A. berda , A. butcheri , A. sivicolus , and A. taiwanensis . Acanthopagrus berda and A. taiwanensis have 3 ½ scale rows between the fifth dorsal-fin spine base and lateral line ( Iwatsuki & Carpenter 2006). Acanthopagrus akazakii , A. butcheri , A. sivicolus and A. randalli are the only currently described species of Acanthopagrus with 4 ½ scale rows between the fifth dorsal-fin spine base and lateral line (see also Iwatsuki & Carpenter 2006 and Iwatsuki et al. 2006).

TABLE 2. Selected characters of Acanthopagrus randalli n. sp., A. akazakii , A. butcheri and A. sivicolus . continued next page A. randalli n. sp. A. akazakii A. butcheri A. sivicolus Holotype and a paratype Holotype and Holotype and 16 non- 1 paratype and 14 non- 11 paratypes type specimens type specimens 176–322 mm SL 66−185 mm SL 54–232 mm SL 112–272 mm SL n =2 n =12 n =17 n= 15

Body colouration 4 or 5 wide black bands Absent in bands Absent in bands or 6–10 Usually 8–12 black very faint dusky black bands, m₀rɵ apparɵnɭ bands, prɵSumaƀIy in aǥiɭaɭɵđ IiVɵ m₀rɵ apparɵnɭ in SpɵcimɵnS aǥiɭaɭɵđ IiVɵ ₀r y₀unǥ

SpɵcimɵnS

*SR5DSLL, Scale rows between fifth dorsal-fin spine base and lateral line; ** Measurements based on: Acanthopagrus

akazakii , n =10, based on holotype and 11 paratype specimens except FRLM 21171 (166 mm SL) and MNHN 2005-1958

(139 mm SL); A. butcheri , n =5, based on MUFS 28685–28688 (198? 215 mm SL, 4 specimens, Perth, Western Australia,

Australia) and WAM P21684 (166 mm, Western Australia, Australia); A. sivicolus , n =5, based on MUFS 1779 (130 mm

SL), MUFS 13165–13166 (152–158 mm SL, 2 specimens), and MUFS 22976, 23054 (172–225 mm SL, 2 specimens).

Iwatsuki & Carpenter (2006) noted that two smaller specimens of four syntypes (BMNH 1874.1.16.2. 1, 87–93 mm SL) of Chrysophrys swinhonis Günther 1874 had 4 ½ scale rows between the fifth dorsal-fin spine base and lateral line (6 ½ in the two other syntypes). Subsequently, the first author re-examined all four syntypes and confirmed that our initial report of 4 ½ scale rows for the two smaller syntypes was erroneous and that the irregular scale rows on these specimens is correctly interpreted as 5 ½ between the fifth dorsal-fin spine base and lateral line. As such, this nominal species is here considered conspecific with A. schlegelii ( Bleeker 1854) which becomes the senior synonym. Other characters of these syntypes also conform to those of A. schlegelii such as pored lateral-line scale counts (51-56) and somewhat slender body ( Akazaki 1962, 1984; this study).

The placement of the eye relative to the unique convex ridge (bulge) of the dorsal profile of the head in Acanthopagrus randalli ( Fig. 1 A B; Table 1 , higher values on both interorbital bulge span / orbit diameter 1.56–2.03 and inɭɵrΟrbiɭaI wiđɭh / Οrbiɭ điamɵɭɵr 1.43–1.71) is clearly distinct from other Form I Blackfin Seabreams with 4 ½ scale rows between the 5th dorsal-fin spine base and lateral line ( Fig. 2 ; Table 2, lower values on both interorbital bulge span / orbit diameter 0.73–1.53 and inɭɵrΟrbiɭaI wiđɭh / Οrbiɭ điamɵɭɵr 0.70–1.47 of three other species). Furthermore, A. randalli differs from A. akazakii , A. butcheri , and A. sivicolus in having only four or five wide bars (six or seven horizontal scale rows in width) on the body. Bands are absent in A. akazakii , absent or 6 to 10 very faint and narrow bars in A. butcheri , and usually 8 to 12 somewhat irregular narrow bars (2 to 4 horizontal scale rows in width) in A. sivicolus ( Figs. 1 , 2 A, B, and D). In addition, the East Asian endemic species, A. schlegelii with the highest counts of 5 ½ or 6 ½ scale rows between the fifth dorsal-fin spine base and lateral line ( Akazaki 1962, 1984) is most similar to A. sivicolus in having a very similar looking silvery-gray coloration with similar narrow black bands on the body ( Fig. 2 C–D). These two species are easily recognizable from A. akazakii , A. butcheri , A. randalli , and A. sivicolus by the 4 ½ scale-row count between the fifth dorsal-fin spine and the lateral line. The coloration of the anal-fin membrane among these four species is also clearly different. In A. randalli it is nearly hyaline in the smaller paratype ( Fig. 1 B) and in the larger holotype it is hyaline with sparse melanophores that are lacking on the membrane of the posteriormost anal-fin rays ( Fig. 3 A). Acanthopagrus akazakii has dense black membranes in anterior anal-fin rays and hyaline in posteriormost anal-fin rays ( Fig. 3 B). The anal-fin membrane in A. butcheri is black from the second anal-fin spine to the third or fourth soft anal-fin ray, the remaining portion being hyaline ( Fig. 3 C). Lastly, A. sivicolus has black or dusky black membranes in the whole anal-fin membrane with each anal-fin ray lighter ( Fig. 3 D). Selected characters comparing these four species are shown in Table 2.

Figures

FIGURE 1. Holotype (A) and paratype (B) of Acanthopagrus randalli n. sp. A, BPBM 33135, 322 mm SL, Bahrain; B, MTUF-P 27226, 173 mm SL, Kuwait.

FIGURE 2. Four sparid species most similar to Acanthopagrus randalli n. sp. A A. akazakii, B A. butcheri, C A. schlegelii and D A. sivicolus. A, MUFS 14209, holotype, 185 mm SL, Noumèa, New Caledonia; B, AMS IB. 1895, holotype, 228 mm SL, Gippsland Lakes, Victoria, Australia; C, Uncatalogued specimen, ca. 350 mm SL, Miyazaki, Kyushu Island, Japan, photographed by N. Aratake; D, Uncatalogued specimen, ca. 190 mm SL, Amami-oshima Island, Ryukyu Island, Japan, photographed by T. Hashimoto.

FIGURE 3. Colouration of anal-fin rays in A Acanthopagrus randalli n. sp., B A. akazakii, C A. butcheri and D A. sivicolus. A, BPBM 33135, holotype, 322 mm SL; B, MUFS 14209, holotype, 185 mm SL; C, WAM P. 21679, 159 mm SL; D, FRLM 12327, 320 mm SL.

Tables

TABLE 1. Counts and morphometric data for the type specimens of Acanthopagrus randalli n. sp. and the holotype and non-type specimens of A. berda (Forsskål, 1775). Measurements expressed as percentages of standard length. Acanthopagrus randalli n. sp.

	BPBM 33135 Holotype	MTUF-P 27226 Paratype
Counts:
Dorsal-fin rays Anal-fin rays	XI, 11 III, 8	XI, 11 III, 8
Pectoral-fin rays	15	15
Pored lateral-line scales Scales above/below lateral line	46 5 ½ / 11 ½	46 5 ½ / 12 ½
Scale rows between fifth dorsal-fin spine base and lateral line Gill rakers	4 ½ 6 + 9 = 15	4 ½ 7 + 10= 17
Standard length (mm)	322	173
Proportions: Body depth	41	43
Head length	33	32
Body width at pectoral fin base Snout length	18 14	16 15
Orbit diameter	7	8
Dermal eye opening Interorbital width	6 12	7 11
Upper- jaw length	14	13
Caudal-peduncle depth Caudal-peduncle length	12 21	13 20
Predorsal length	42	43
Preanal length Prepelvic length	70 37	63 37
Dorsal-fin base	55	55
Anal-fin base Caudal-fin length	15 27	15 28
Pelvic-fin spine	11	14
First pelvic-fin ray Longest pectoral-fin ray	20 35	23 36
First dorsal-fin spine	5	6
Second dorsal-fin spine Third dorsal-fin spine	7 12	11 15
Fourth dorsal-fin spine	14	16
Fifth dorsal-fin spine Sixth dorsal-fin spine	13 13	15 15
Last dorsal-fin spine	10	15
Longest dorsal-fin ray	10	14 continued next page