Ctenogobiops maculosus (Fourmanoir, 1955)

Bogorodsky, Marcelo Kovačić Sergey V. & Randall, John E., 2011, Redescription of the Red Sea gobiid fish Ctenogobiops maculosus (Fourmanoir) and validation of C. crocineus Smith, Zootaxa 3054, pp. 60-68 : 61-65

Ctenogobiops maculosus (Fourmanoir, 1955)

( Figs. 1–3 )

Cryptocentroides maculosus Fourmanoir in Roux-Estève & Fourmanoir, 1955: 101 (type locality, Abu Latt Island, Red Sea).

Material examined. Holotype: MNHN 52-297, male, 50.9+ 16.5 mm Red Sea, Saudi Arabia, Farasan Bank, Abu Latt Island, R/V Calypso, 1952 .

Nontype material. HUJ 9454 (former E62/580), male, 39.7+ 12.3 mm, and female, 27.8+ 7.8 mm, Red Sea, Dahlak Archipelago, Nocra, 23 March 1962; HUJ 9457 (former E62/3678), two males, 43.0+15.4 and 40.7+ 13.5 mm, and one female, 25.1+ 7.7 mm, Dahlak Archipelago, Um Aabak, 6 April 1962; HUJ 9458 (former E62/4322), female, 28.7+8.0 mm, Dahlak Archipelago, Entedebir, 7 April 1962.

Diagnosis. Dorsal rays VI + I,11; anal rays I,11; pectoral rays 18–19; longitudinal scale series 58–66; body slender, depth 5.0– 5.6 in SL; dorsal profile of snout forming an angle of about 60° to horizontal axis of head and body; gill opening reaching forward to, or slightly anterior to, a vertical at posterior margin of preoperculum; second dorsal spine longest (in males 1.2–2.2 times longer than third spine; in females 1.2–1.6 times longer than third spine); caudal-fin length 2.8–3.6 in SL; body with four longitudinal rows of dark brown spots, the first three with dashes alternating with small spots, the lowermost of seven or eight round to slightly oval spots (the third one small); postorbital head crossed by four steeply oblique rows of dashes and spots, the first short from behind eye, the second from behind corner of mouth to above anterior fourth of opercle; a V-shaped dark brown mark dorsoposterior on snout; ventral part of body in life with small vertical yellow marks, mostly over abdomen; pectoral fins in life with a white spot at upper base and a larger one near middle of fin about one-third fin length from base.

Description. Dorsal rays VI + I,11; anal rays I,11; pectoral rays 18–19; the two uppermost and lower one or two rays unbranched; pelvic rays I,5, united as a disc, with a well-developed frenum; segmented caudal rays 17, the middle 13–15 branched; upper and lower procurrent caudal rays 5 or 6; longitudinal scale series 58–66; scales in transverse series 18–22 (lower count of 18 scales from two small specimens where area around the first dorsal fin is naked, others 20–22); lower limb gill rakers 9.

Head, nape, and chest naked; scales on body mainly ctenoid, becoming cycloid above a line between upper end of gill opening and posterior end of base of first dorsal fin, on abdomen, and above front of anal fin; cycloid scales embedded and barely visible (in small specimens, some of these areas seem scaleless); no scales on fins, except basally on caudal fin.

Body slender, depth 5.2 (5.0–5.6) in SL, and compressed, width 1.5 (1.4–1.6) in body depth; head length 3.2 (3.0–3.3) in SL; head width 1.9 (1.7–1.9) in head length; dorsal profile of snout steep, forming an angle more than 45* to horizontal axis of head and body; snout length 5.1 (4.7–5.6) in head length; orbit diameter 3.7 (3.4–4.1) in head length; upper edge of eye extending slightly above dorsal profile of head; interorbital space narrow, the least width 26.2 (21.3–29.3) in head length; caudal-peduncle depth 8.6 (8.1–9.0) in SL; caudal-peduncle length 5.1 (4.6– 5.3) in SL; predorsal length 2.8 (2.6–3.0) in SL; preanal length 1.7 (1.6–1.8) in SL; prepelvic length 2.8 (2.6–3.0) in SL.

Mouth oblique, the lower jaw slightly projecting; maxilla reaching to below middle of eye, the upper-jaw length 3.1 (2.8–3.4) in head length; front of upper jaw with two pairs of large incurved canine teeth, separated at symphysis; side of jaw with an outer row of incurved canine teeth smaller than the four front teeth, and several inner rows of small teeth; front of lower jaw with an outer row of incurved canine teeth, shorter laterally; one to three large incurved canine teeth about halfway back in jaw; several inner rows of small teeth; tongue bilobed. Gill opening reaching forward to, or slightly anterior to, a vertical at rear margin of preopercle; gill membranes narrowly attached to isthmus.

First dorsal fin narrowly separated from second dorsal fin, its origin over pelvic-fin base; first dorsal spine 4.9 (4.3–5.6) in SL; second dorsal spine, 3.4 (2.6–5.0) in SL; third dorsal spine, 5.1 (3.4–6.0) in SL; second spine of first dorsal fin longest in all specimens (in males 1.6–1.8 times longer than first spine and 1.2–2.2 times longer than third spine; in females 1.1–1.5 times longer than first spine and 1.2–1.6 times longer than third spine); second spine of first dorsal fin 1.6–2.0 times longer than body depth in males, 1.1–1.5 times longer in females; origin of second dorsal fin on a vertical with anus; spine of second dorsal fin 2.4 (2.3–2.7) in head length; longest dorsal soft ray 5.8 (5.3–6.5) in SL; base of dorsal fins 2.1 (2.1–2.2) in SL. Origin of anal fin below base of 1st to 2nd dorsal soft rays; anal spine 2.7 (2.3–3.5) in head length; longest anal soft ray 6.1 (5.5–6.8) in SL; anal-fin base 4.1 (3.9–4.3) in SL. Caudal fin rounded, 3.2 (2.8–3.6) in SL, longer than head or equal in males (0.9–1.0), shorter than head in females (1.1). Pectoral fins reaching above anal-fin base, fin length 3.5 (3.3–3.6) in SL. Pelvic fins reaching origin of anal fin or ending slightly anterior, 4.5 (4.3–4.6) in SL; pelvic spine 11.8 (10.9–12.6) in SL.

Cephalic lateral-line system ( Fig. 2 ): anterior and posterior oculoscapular, and preopercular canals, with pores σ, ƛ, κ, ω, α, β, ρ, ρ 1, ρ 2, and γ, δ, ε, respectively. Rows of sensory papillae counted on left side of HUJ 9457, 40.7 mm SL: Preorbital: snout with three rows in median preorbital series: internal longitudinal row r (2), outer row s as single papilla below pore σ, anterior row s3 as single papilla above upper lip. Lateral series c in four parts: superior c2 (2) in angle between AN and PN; middle c1 (2) close to AN; inferior anterior c1 and inferior posterior c2 as two single papillae above lips. Suborbital row: longitudinal rows a and c, including cp, without transverse proliferation; row a just below rear half of eye (4); c below frontal part of eye (5), beginning anteriorly with two papillae, one above the other three longitudinally arranged, ending bellow mideye; single cp papilla just below beginning of row b, single cp’ below and behind cp. Longitudinal rows b and d with smaller papillae compared to rows a and c. Row b (11) below row a. Longitudinal row d with separate supralabial (12) and horizontal part (7). Preoperculo-mandibular: external row e and internal row i divided into anterior (e: 13, i: 11), and posterior sections (e: 19, i: 10); row f as a pair of single papillae between anterior end of row i. Oculoscapular: anterior longitudinal row x1 divided in anterior section (13) from above pore β to above row z and posterior section (8) above row q, posterior longitudinal row x2 (6) anteriorly beginning above pore ρ 2; row z (6) behind and above pore γ, row q as three large longitudinally arranged papillae between pores ρ and ρ 1, row y as single papilla behind pore ρ2. Axillary rows as1 (7), as2 (7), as3 (11), la1 (4) and la2 (2) present. Opercular: transverse row ot (15); superior longitudinal row os (4); and inferior longitudinal row oi (4). Anterior dorsal: row g (9), row m (8) and row h (6) present; row n as single papilla behind pore ω and row o as single papilla in front of row g.

Color of nontype specimen ( Fig. 1 B): body yellowish brown with four longitudinal rows of brown spots, the uppermost mainly as dashes along base of dorsal fins, the second at level of upper end of gill opening, and the third midlateral (the second and third rows with the larger spots horizontally elongate); lowest row ventrally on body with six rounded spots of similar intensity and nearly evenly spaced; head with no short dark bands between side of upper lip and eye; two narrow, oblique, broken, brown bands on postorbital head, the first passing from end of upper jaw to upper edge of preopercle, the second across opercle; a median, V-shaped, dark brown mark dorsally on snout; brown spots on predorsal area in longitudinal rows: three or four spots above upper edge of opercle, three spots at level of upper part of eye, and two or three in front of base of first dorsal fin; dorsal fins without visible pigmentation; caudal fin with a vertical row of three brown spots at base, the middle one darkest; anal fin with basal and submarginal brown bands; paired fins without pigmentation, except base of pectorals fins with an upper and lower brown spot.

Life color from underwater photographs taken by the second author in the Red Sea off El Quseir, Egypt ( Fig. 3 A) and Shams Alam ( Fig. 3 B). Light greenish gray dorsally, pale gray ventrally, with four longitudinal rows of dark brown spots on body, the principal spots of first three rows horizontally elongate, those of third (midlateral) row narrowly elliptical; small dark brown spots between principal spots, and a few between first and second rows; fourth row ventrally on abdomen and above anal fin, with six, near-round, nearly evenly spaced, dark brown spots of about equal size; base of caudal fin with a vertical row of three dark brown spots, the middle one largest; scattered, small, vertically elongate, yellow marks on ventral half of body, mainly on abdomen, some partly brown; side of postorbital head with three oblique rows of brown-edged, yellow dashes, the first posterior to eye, the first two rimmed with bright blue; predorsal area with three rows of small brown spots; a V-shaped black mark dorsoposterior on snout; iris yellowish with three irregular black marks (none ventral), and a pale yellow rim to pupil; dorsal fins unmarked except for a faint dark curved line at base of first dorsal and a row of dark dots at base of second dorsal; anal fin with a broad basal light brown band and blackish border; pectoral fins with a prominent white spot at upper base and a second white spot near middle of fin about one-third fin length from base; pelvic fins translucent.

Remarks. The original description of Ctenogobiops maculosus was lacking in some diagnostic characters, such as the size of the gill opening. The holotype has a rounded caudal fin, not lanceolate as described, and cycloid scales, though barely visible, are present. Also, the color description was in part misleading.

The second author’s underwater photographs of C. maculosus were taken off the Red Sea coast of Egypt. The holotype was collected from Abu Latt Island at the northern end of the Farasan Bank just off the southernmost end of Saudi Arabia. Other specimens we have examined were collected from the Dahlak Archipelago off Eritrea. We have found no specimens or underwater photographs extralimital to the Red Sea.

Thacker et al. (2010) gave two localities for C. maculosus , Red Sea and Taiwan. No specimen is listed for Taiwan, just tissue sample C 140 in the fish tissue collection of the Natural History Museum of Los Angeles County. Their illustration of C. maculosus ( Fig. 3 b), with no locality, shows a preserved specimen with what appears to be a large tissue sample taken from the abdomen. We believe this specimen is C. crocineus from the shape of the snout, the broken dark lines from the eye across the lips, and just two, low-angle, broken, dark lines across the preoperculum and operculum. Christine Thacker was contacted to check the specimen, and she agrees that it is C. crocineus , therefore a first record for Taiwan.

Figures

FIGURE 1. Ctenogobiops maculosus A. holotype, male, MNHN 52 - 297, 50.9 + 16.5 mm, Abu Latt, Saudi Arabia (C. Ferrera). B. non-type specimen, HUJ 9457, male, 43.0 + 15.4 mm, Um Aabak, 6 April 1962 (M. Kovačić).

FIGURE 2. Ctenogobiops maculosus, cephalic sensory papillae and pores, HUJ 9457, male, 40.7 + 13.5 mm. AN, PN, anterior and posterior nostrils; terminology of the lateral-line system follows Sanzo (1911) and Miller (1986). Scale = 5 mm (M. Kovačić).

FIGURE 3. Ctenogobiops maculosus, underwater photographs, A: Utopia Beach, El Quseir, Egypt (S. V. Bogorodsky). B: Shams Alam, Egypt (S. V. Bogorodsky).