Diplogrammus gruveli Smith, 1963

Fricke, Ronald, Bogorodsky, Sergey V. & Mal, Ahmad O., 2014, Review of the genus Diplogrammus (Teleostei: Callionymidae) of the Red Sea, with description of a new species from Saudi Arabia, Journal of Natural History 48 (39 - 40), pp. 2419-2448 : 2425-2429

Diplogrammus gruveli Smith, 1963

Gruvel’ s dragonet

( Figures 1 , 2 , 3 , 11A ; Tables 1, 3)

Diplogrammus goramensis (non Bleeker, 1858): Chabanaud 1932: 832 (Great Bitter Lake, Suez Canal, Egypt). Gruvel and Chabanaud 1937: 28 (Great Bitter Lake, Suez Canal, Egypt).

Diplogrammus (Diplogrammoides) gruveli Smith, 1963: 551–552 , figure 2, pl. 86 G (Great Bitter Lake/ Suez Canal, type locality). Fricke 1981: 689 (part). Fricke 1982: 72 (checklist). Fricke 1983a: 524 (revision). Fricke 1984: 4. Fricke et al. 1984: 107. Dor 1984: 236 (checklist).

Diplogrammus gruveli: Fricke and Zaiser 1982: 256 . Goren and Dor 1994: 62 (checklist). Fricke 2002: 47 (checklist). Golani and Bogorodsky 2010: 45 (checklist).

Holotype: SAIAB 154 ( Great Bitter Lake , Suez Canal, Egypt).

Paratypes: MNHN 1963–0186 (1, Great Bitter Lake , Suez Canal, Egypt) .

Red Sea material: RMNH 19317 (1, Great Bitter Lake , Suez Canal, Egypt) , 19326 (1, Great Bitter Lake , Suez Canal, Egypt) , 19328 (1, Great Bitter Lake , Suez Canal, Egypt) .

Diagnosis

Dorsal-fin spines IV, rays 7–9; anal-fin rays 6 or 7; no free opercular flap of skin or branches of lateral line; preopercular spine with a slightly upcurved main tip, formula 1 ― 4― 5 1; first dorsal fin without filaments, first to third spines significantly longer than the first ray of the second dorsal fin; caudal fin truncate, with short filaments in males; body below ventrolateral fold of skin white or yellowish; anal fin translucent in males, outer half dusky, anal-fin rays spotted; head, prepectoral area and lower half of caudal fin with small blue spots, but head without blue lines.

Description

First dorsal fin with IV spines, second dorsal fin with 7 to 9 soft rays, last ray divided at base; anal-fin rays 6 or 7, last ray divided at base; pectoral-fin rays 16 or 17, upper and lower one or two rays unbranched; pelvic fin with I spine and 5 soft rays; caudalfin rays 11 or 12. Fin-ray formula: D 1 IV; D 2 vi,1 – viii,1; A v,1 – vi,1; P 1 i-ii,13–14,iii (total 16–17); P 2 I,5; C (i),i,7,ii,(0-i).

Body elongate and slightly depressed. Body depth 7.2–8.4 in SL. Head slightly depressed, 4.0– 4.3 in SL. Eye 1.9–3.1 in head length. Interorbital distance 3.6–4.6 in eye diameter. Preorbital length 2.95–3.2 in head length. Occipital region with a smooth bony plate. Branchial opening pore-like, dorsal in position. Opercle without a free flap of skin. Maxilla not projecting laterally in males. Preopercular spine length 3.9–4.2 in head length; preopercular spine with a slightly upcurved main tip, a smooth ventral margin, a small antrorse spine at its base, and four or five upcurved spinules at its dorsal margin (formula: 1 ― 4―5 1). Urogenital papilla elongate in the male, 6.5– 16.0 in head length. Lateral line reaching from eye to end of fourth branched caudalfin ray (counted from above), without any additional dorsal or ventral branches along the sides of the body; the lines of the opposite sides are interconnected by a commissure across the occipital region. Sides of body with a continuous ventrolateral fold of skin below the lateral line. Caudal peduncle length 4.2–5.2 in SL. Caudal peduncle depth 15.4–20.0 in SL.

First dorsal fin high in the male, without filaments; first spine longest, 2.3–4.2 in SL. Predorsal(1) length 3.15–3.55 in SL. Margin of second dorsal fin straight; rays unbranched except for the last which is divided at its base; last ray longest, elongate in the male. Predorsal(2) length 2.1–2.25 in SL. First anal-fin ray on a vertical through mid-base of second membrane of second dorsal fin. Anal-fin rays unbranched, the last divided at its base; last ray longest, elongate in the male. Preanal-fin length 1.85– 2.00 in SL. Pelvic fin reaching back to base of second anal-fin ray. Pelvic-fin length 3.1–3.3 in SL. Prepelvic-fin length 3.8–4.0 in SL. Membrane connecting fifth ray of pelvic fin with pectoral-fin base attached to base of seventh or eighth pectoral-fin ray. Pectoral fins reaching to above second anal-fin ray. Caudal fin truncate, fin rays in male with short filaments; caudal-fin length 3.0– 3.6 in SL.

Colour in life (based on photograph of freshly collected specimen, Figure 3 )

Head and body greenish yellow, back and sides of body with dark brown spots and marblings, and cream spots and blotches of various sizes. Lateral line marked with dark brown spots in groups of two to four. Ventrolateral fold of skin alternatingly marked with groups of two white spots and one dark brown streak. Sides of head, pectoral-fin base, pelvic fins and membrane connecting pelvic fin with pectoral-fin base in male with small light blue spots. First dorsal-fin membranes greenish yellow in male, spines cream, with dark brown spots. Second dorsal-fin membranes in male greenish yellow, with horizontal and oblique blue lines; fin-rays cream, with dark brown spots. Anal-fin rays cream, with dark brown spots, distal and posterior parts of anal-fin membranes dark grey. Pectoral fins greenish yellow, rays cream, dorsally spotted with dark brown, below with greenish yellow. Caudal-fin membranes dorsally greenish yellow, with horizontal and oblique blue lines, ventrally dark brown, with bluish white ocelli.

Colour of preserved material

Similar to live coloration, but the greenish yellow fades to light brown, and the bluish spots fade to white.

Distribution and habitat

Red Sea ( Egypt: Gulf of Suez; Suez Canal) ( Figure 1 ). In the Gulf of Suez trawled by small shrimp trawlers from depths of about 10 metres in open sand areas, often in seagrass beds.

Remarks

Based on the lacking free flap of skin on the opercle, and the unbranched lateral line, Smith (1963: 551) placed this species in a separate subgenus Diplogrammoides . Nakabo (1982: 97) removed the subgenera and synonymized Diplogrammoides with Diplogrammus .

The intraspecific variation of dorsal and anal fin counts in this species is remarkable ( Table 1). Other species of Diplogrammus nearly constantly have a fin-ray formula of D 1 IV; D 2 vii,1; A vi,1, which is only found in two of the five examined specimens of Diplogrammus gruveli . The other three specimens have one or two deviations from this formula. This high variation in fin-ray numbers may be due to a limited distribution range and low population size.

Originally, this species was known only from Great Bitter Lake in the artificial Suez Canal. Fricke (1983a: 628–629) discussed the original distribution range of the species, and came up with two alternative hypotheses: either lagoons in the south-eastern Mediterranean, or from lagoons and salt lakes near the Gulf of Suez in the northern Red Sea. The species was collected and photographed in the northern Gulf of Suez by the second author ( Figure 3 ), so the problem was solved; Diplogrammus gruveli is therefore here defined as a Red Sea species.

Figures

Figure 1. Map of collecting localities of Diplogrammus in the Red Sea. (Stars) D. gruveli; (squares) D. infulatus; (triangles) D. paucispinis; (circles) D. randalli.

Figure 2. Diplogrammus gruveli, RMNH 14328, male, 41.8 mm SL, Great Bitter Lake, Suez Canal (from Fricke 1983a: figure 156). (A) Lateral view; (B) left preopercular spine.

Figure 3. Diplogrammus gruveli, uncatalogued, male, 56 mm SL, Egypt, Gulf of Suez, off Suez, S. V. Bogorodsky.

Figure 11. Male first dorsal fin in species of Diplogrammus. (A) D. gruveli; (B) D. infulatus; (C) D. paucispinis; (D) D. randalli; (E) D. pygmaeus; (F) D. goramensis; (G) D. xenicus.