Polysteganus coeruleopunctatus ( Klunzinger 1870 )

Iwatsuki, Yukio & Heemstra, Phillip C., 2015, Redescriptions of Polysteganus coeruleopunctatus (Klunzinger 1870) and P. lineopunctatus (Boulenger 1903), with two new species from Western Indian Ocean, Zootaxa 4059 (1), pp. 133-150 : 135-140

Polysteganus coeruleopunctatus ( Klunzinger 1870)

English name: Blueskin Seabream

Figures 1 A, 2A; Table 1

Dentex (Polysteganus) coeruleopunctatus Klunzinger 1870:763 (Al-Qusayr [Kosseir], Egypt, Red Sea); Fricke 1992:18 (same as original description); Fricke 2005:60 (same as original description).

Polysteganus coeruleopunctatus ; Sato 1976:98, unnumbered color sub-adult and large adult photographs (East Africa); Dor 1984:160 (Red Sea); Baranes & Golani 1993:308 (Red Sea); Goren & Dor 1994:44 (Red Sea); Manilo & Bogorodsky 2003:S109 (Red Sea).

Lectotype. ZMB 7989, 258 mm SL, [Kosseir] Al-Qusayr, Egypt, Red Sea ( Fig. 2 A).

Paralectotype. SMNS 1873, 223 mm SL (X), same data as for the Lectotype.

Other material examined. HUJF 13901, 2 specimens, 126−127 mm SL (X), Eilat, Red Sea; HUJF 20120, 226 mm SL, Eilat, Israel; SAIAB 13464, 223 mm SL, off Ras Ngomeni, Ras Ngomeni, Kenya; SAIAB 42677, 3 specimens, 161–184 mm SL (X), Eilat, Red Sea; SAIAB 42816, 332 mm SL, off Kilifi, Mombasa, Kenya; SAIAB 48180, 148 mm SL, off Mozambique (23.47°S, 35.72°E).

Diagnosis. Distinguished from all congeners of Polysteganus by the following combination of characters: scale rows above lateral line 6½; scales rows between 5th dorsal-fin spine base and lateral-line scale 5½ or 6½; pored lateral-line scales 51 or 52; suborbital depth subequal to or greater than orbit diameter; dorsal-fin rays reddish pink as well as similar reddish pink on upper margin dorsal-fin ray (no clear yellow or faint yellowish); 7 or 8 faint irregular blue spotted lines on body, not visible from all angles; reddish membranes on caudal-fin lobes and caudal fin with clear white lowest margin of lower caudal fin lobe; no blue iridescence on each scale of dorsal and lateral sides of whitish pink body; canines large, both upper and lower canines on both jaws usually visible even when mouth closed; deep body, 44–46% (mean 44%) of SL; anal- and pelvic- fin rays whitish or reddish hyaline; no yellow (white) rear margin of branchiostegal rays and membrane; weak bony bulge before and above eye, forming a low median ridge in larger specimens of over 30 cm SL; caudal fin moderately forked.

Description. Counts and proportional measurements as percent of standard length (SL) of the type and other specimens of Polysteganus coeruleopunctatus are given in Table 1 .

Body depth relatively deeper; head robust, rostro-occipital profile gently curved; interorbital fully scaly, scales extending to just above anterior and posterior nostrils, anterior nostrils small rounded and posterior nostrils oval; orbit diameter greater than interorbital width; maxilla naked, its posterior end not reaching vertical at front edge of eye, rear margin of maxilla not concealed by infraorbitals; jaw robust, especially upper jaw; canines generally stout, 4 in upper and 6 in lower jaw (two outermost canines in upper jaw greater in size than 2 medial canines, and 2 outermost canines of lower jaw greater than 4 medial canines, but one or two canines often missing or broken in both jaws); an outer lateral row of conical teeth and a series of villiform teeth on inner side of outer lateral teeth row; mandibular profile straight; rear margin of preopercle rounded and serrated, preopercle flange scaly, a narrow naked area (preopercle with keel- like ridge), separating preopercle flange scaly area and cheek scales; first 3 dorsal-fin spines progressively longer, fourth spine longest and slightly greater than snout length; no sheath scales on dorsal and pelvic-fin rays; predorsal length slightly greater than body depth, and clearly less than dorsal-fin base length; lateral line gently curved, generally parallel to curved dorsal profile between dorsal outline and curved lateral line, from nape to peduncle, but somewhat deeper anteriorly than posteriorly, giving an impression of a deeper body than that of the similar species, P. lineopunctatus ( Figs. 1–2 ); pectoral-fin base scaly and rounded posteriorly, two or three lowest rays slightly extended posteriorly, compared with rays above ( Figs. 1–2 , being similar to that of Fig. 2 B of P. lineopunctatus ), the fin tip reaching beyond vertical at anus, and almost reaching vertical at first anal fin spine base, its length greater than head length; first pelvic-fin ray length clearly greater than fourth dorsal-fin spine length, fin tip not reaching beyond vertical at pectoral-fin tip and rear margin of anus; soft dorsal and anal fins with no scales; anal fin with low scaly sheath, anal-fin spines slender, second slightly greater than third, subequal to orbit diameter; caudal fin lobes broad and wide, caudal fin moderately forked ( Figs. 1 A, 2A); scales ctenoid; gill-rakers lanceolate; vertebrae 10+14.

Color when fresh, based on color photographs of specimens (HUJF 20120, 227 mm SL ( Fig. 1 A); J.E. Randall’s photograph (Gulf of Aqaba, Red Sea, BPBM 39500, 167 mm SL): head and body uniform bright red with silvery-golden reflection on each scale, upper head and dorsolateral part of body deeper yellowish red than lower head and abdominal part of body; iris golden and pupil black; all fins uniform reddish hyaline, especially in membrane of dorsal-fin and very pale reddish and whitish hyaline in other fins except caudal fin reddish.

Color of preserved specimens: upper sides of head and trunk uniform yellowish-tan.

Polysteganus coeruleopunctatus Polysteganus lineopunctatus

ZMB 7989, Lectotype; SMNS Other specimens: HUJF BMNH 1903.2.6.5 SAM 9908, 1 of 2 Other specimens: SAIAB

1873, Paralectotype 13901, 2 specimens, Holotype syntypes of Dentex 17470, 318 mm SL, SAIAB

125–126 mm SL, HUJF natalensis * 29416, 189 mm SL, SAIAB

20120, 226 mm SL, 48180, 148 mm SL, SAIAB

SAIAB 13464, 223 mm SL, 82139, 3 specimens, 92-196

SAIAB 42677, 150 mm SL, mm SL

and SAIAB 42816, 332 mm

SL

n = 2 n = 6 n = 1 n = 1 n = 7 Suborbital depth 8.2; 7.7 6.5–9.2 (7.8) 10.7 6.1 6.4–9.4 (7.9) First dorsal-fin spine length 6.7; 6.4 6.4–7.6 (7.1) 7.4 8.7 5.7–7.8 (7.0) Second dorsal-fin spine length 10.5; 9.9 9.7–12.7 (11.1) 10.0 12.2 8.8–12.1 (10.7) Third dorsal-fin spine length 14.1; 13.2 12.4–15.1 (13.9) 13.0 16.6 12.2–15.8 (13.8) Fourth dorsal-fin spine length 14.2; 14.6 13.6–15.6 (14.6) 14.9 18.1 13.1–16.3 (14.4) First dorsal-fin ray length 10.5; 10.4 9.5–11.7 (10.6) 7.9 9.6 10.2–13.5 (11.6) First anal-fin spine length 7.7; 6.8 6.4–8.7 (7.3) 6.7 6.4 6.0–12.4 (8.3) Second anal-fin spine length 12.5; 12.3 11.3–15.6 (13.5) 12.3 11.7 10.8–16.3 (13.4) Third anal-fin spine length 10.7; 10.8 10.3–13.0 (11.7) 9.1 11.1 10.3–14.1 (11.8) First anal-fin ray length 9.3; 10.7 8.9–13.0 (11.1) 9.8 12.8 9.5–14.1 (11.5) Pelvic-fin spine length 16.6; 16.8 15.7–17.5 (16.4) 16.1 17.8 14.5–16.7 (15.5) First pelvic-fin ray length 19.8; 22.2 21.1–23.4 (22.4) 20.9 23.3 20.8–26.1 (22.7) Caudal peduncle depth 12.4; 12.6 11.3–12.1 (11.7) 9.8 13.4 10.6–12.2 (11.6) Caudal peduncle length 18.5; 24.0 19.9–23.1 (20.9) 19.5 20.6 20.0–22.3 (21.0) Predorsal length 43.1; 42.1 39.1–44.3 (42.1) 44.4 41.7 39.2–45.7 (42.7) Preanal length 64.3; 63.6 60.4–64.6.(62.1) 67.4 65.0 61.6–64.8 (63.2) Prepelvic length 40.2; 38.6 39.6–45.3 (41.0) 41.4 42.2 38.9–45.9 (40.7) Dorsal-fin base 50.9; 51.1 48.1–55.2 (52.3) 47.9 53.4 50.3–55.2 (52.2) Anal-fin base 17.4; 16.1 15.7–20.3 (17.8) 16.5 18.4 17.9–20.3 (18.8)

One of two syntypes of Dentex natalensis was lost according to M. Bougaardt ( SAM, pers. comm.).

Distribution. Polysteganus coeruleopunctatus has been reported from the Western Indian Ocean including the Red Sea (type locality). The species was photographed in the East African Fish Faunal Research (probably Kenya) by Sato (1977:98, unnumbered color sub-adult and large adult photographs) and might thus occasionally occur there. However, specimens formerly identified as P. coeruleopunctatus from Mozambique and South Africa are reidentified as P. lineopunctatus ( Boulenger 1903) in this study.

Remarks. Polysteganus coeruleopunctatus ( Klunzinger 1870) has long been recognized as a valid species from the Western Indian Ocean and its distribution was considered as from the Red Sea and East Africa, to KwaZulu-Natal south coast and Eastern Cape Province, South Africa ( Smith & Smith 1986; van der Elst 1981; Heemstra & Heemstra 2004). However, another species in synonymy, P. lineopunctatus ( Boulenger 1903) , is recognized by us as valid. Specimens formerly identified as P. coeruleopunctatus from South Africa and Mozambique were confirmed as P. lineopunctatus in this study (see next section of P. lineopunctatus ).

There are two syntype specimens of Dentex (Polysteganus) coeruleopunctatus Klunzinger 1870 : Al-Qusair, Egypt, Red Sea. ZMB 7989 (258 mm SL) is designated as the lectotype because of its good condition and the other specimen (SMNS 1873, 223 mm SL) is designated as paralectotype in order to avoid further confusion with Polysteganus taxonomy.

Figures

FIGURE 1. Polysteganus coeruleopunctatus A and P. lineopunctatus (B). A), HUJF 20120, 226 mm SL, Eilat, Israel, Red Sea, photographed by D. Golani; B), SAIAB 82139, Mozambique, southwestern Indian Ocean (21 ° 35 ' S, 35 ° 32.3 ' E), photographed by O. Alvheim.

FIGURE 2. Polysteganus coeruleopunctatus (A) and P. lineopunctatus (B). A), ZMB 7958, lectotype, 258 mm SL, [Kosseir] Al-Qusair, Red Sea B) BMNH 1903.2. 6.5, holotype, 320 mm SL, KwaZulu-Natal, South Africa, southwestern Indian Ocean, photographed by J. Maclaine.

Tables

TABLE 1. Counts and proportional measurements of type and non-type specimens of Polysteganus coeruleopunctatus (Klunzinger 1870) and P. lineopunctatus (Boulenger 1903), expressed as percentages of standard length (mean in parenthesis).

	Polysteganus coeruleopunctatus ZMB 7989, Lectotype; SMNS 1873, Paralectotype n = 2	Other specimens: HUJF 13901, 2 specimens, 125–126 mm SL, HUJF 20120, 226 mm SL, SAIAB 13464, 223 mm SL, SAIAB 42677, 150 mm SL, and SAIAB 42816, 332 mm SL n = 6	Polysteganus lineopunctatus BMNH 1903.2.6.5 SAM 9908, 1 of 2 Holotype syntypes of Dentex natalensis * n = 1 n = 1	Other specimens: SAIAB 17470, 318 mm SL, SAIAB 29416, 189 mm SL, SAIAB 48180, 148 mm SL, SAIAB 82139, 3 specimens, 92–196 mm SL n = 7
Counts: Dorsal-fin rays Anal-fin rays Pelvic- and pectoral-fin rays Pored lateral-line scales Scale rows between fifth dorsal fin spine base and lateral line Scale rows above and below lateral line Gill rakers	XII, 10; XII, 10 III, 8; III, 8 I, 5, 16; I, 5, 15 52; 51 5 ½; 5 ½ 6 ½ / 15 ½; 6 ½ / 15 ½ 7 + 13 = 20; 7 + 12 = 19	XII, 10 III, 8 I, 5; 15–16 51–52 5 ½–6 ½ 6 ½ / 15 ½–16 ½ 6 + 12 = 18	XII, 10 XII, 10 III, 8 III, 8 I, 5; 16 I, 5; 15 54 55 5 ½ 5 ½ 7 ½ / 16 ½ 7 ½ / 15 ½ 6 + 12 = 18 7 + 12 = 19	XII, 10 III, 8 I, 5; 15–16 53–54 5 ½ 7 ½ / 15 ½–16 ½ 6 + 12 = 18
Standard length	258 mm SL; 223 mm SL	125–332 mm SL	285 mm SL 283 mm SL	92–318 mm SL
Proportions (% SL): Head length Body depth Body width at pectoral fin base Pectoral-fin ray length Snout length Upper jaw length Interorbital width Orbit diameter Dermal eye opening	34.5; 33.2 43.8; 45.8 18.4; 15.7 36.3; 37.2 13.8; 11.4 13.2; 12.6 8.3; 9.2 10.0; 12.6 8.3; 10.8	33.7–37.3 (34.9) 43.5–45.1 (44.2) 14.0–17.9 (16.7) 35.0–37.0 (35.9) 12.0–14.7 (13.1) 11.2–12.7 (11.9) 9.0–10.9 (9.9) 9.6–12.7 (11.8) 8.7–10.2 (9.5)	34.7 33.0 42.5 41.7 14.9 14.1 31.2 33.9 12.8 10.8 11.4 10.8 11.8 9.2 10.2 8.7 7.4 7.8	32.6–37.5 (35.1) 40.3–42.9 (41.9) 13.6–16.9 (15.7) 36.2–39.7 (37.9) 12.0–14.4 (13.1) 11.8–12.3 (12.1) 9.7–11.3 (10.6) 11.1–15.1 (12.9) 8.2–13.7 (11.3) ......continued on the next page