Systematic position

Family Callionymidae Bonaparte, 1831

Genus Callionymus Linnaeus, 1758

Callionymus gardineri Regan, 1908

Longtail dragonet (Figure 1A–C; Table 1)

Figure 1.

Callionymus gardineri from northwestern India, (A) fresh, (C) preserved, and (B) preopercle spine. Scale A and C = 10 mm.

Table 1.

Morphometric and meristic data of Callionymus gardineri and C. omanensis from India, compared with previously available data

Notes: M, male; F, female; U, unknown sex; *damaged. The proportions and counts of female C. omanensis were given in parentheses and brackets.

Type locality: Cargados Carajos Island, southwest Indian Ocean, depth 20–30 fathoms (35–55 m).

Callionymus gardineri Regan, 1908: 248, pl. 30, fig. 5

Callionymus maldivensis Regan, 1908: 247, pl. 30, fig. 3

Material examined. KU/COFS/MUS/010262 (79.4 mm standard length [SL], male), 1 ex., 29 October 2024 (Figure 1A and B), KU/COFS/MUS/010264 (117.2 and 159.0 mm SL, male), 2 ex., 5 November 2024, 20°54ʹ27″N 70°23ʹ02″E, Veraval Fishing Harbour, northwestern coast of India, collected by S. Ragul, trawled off Gujarat, Northeastern Arabian Sea.

Identification. First dorsal-fin spines IV; second dorsal-fin elements viii, 1; anal-fin elements vii, 1; pectoral-fin rays ii, 16–18, i = 19–21; pelvic-fin elements I, 5; caudal-fin rays (i), i, (6), ii, 2, (i); preopercular spine formula $1\frac{{10}}{ - }1$. For a detailed comparison of meristic and morphometrics, see Table 1.

Body and head: Elongated body and head, ventrally flat. Male urogenital papilla small 13.2–13.6 in HL. Large eyes (2.5–3.0 in head length, HL) with a narrow interorbital space, 9.6–15.8 in eye diameter (ED). Head with almost a straight nape. Body more tapering at the tail, long caudal peduncle 6.2–6.8 in SL with the least depth, 22.6–22.7 in SL. Head, long preopercular spine (3.3–4.1 in SL) with a long main tip, smooth and straight; base with a single strong antrorse spine, 6–12 small antrorse serrae at its dorsal margin (Figure 1B). Mouth small, subterminal, maxilla reaching to a vertical through origin of eye, preorbital distance 3.1–3.3 in HL; small upper law, 2.6–2.8 in HL.

Fins: The first dorsal fin filamentous in males but as the specimen collected from trawl bycatch, the fin was damaged, 4.0–4.9 in SL even though slightly higher than the second dorsal fin, 5.7–6.1 in SL. Last ray of both second dorsal and anal fin: unbranched and divided at its base.

Colouration (fresh specimen) (Figure 1A). Body dorsally pale to dark brownish filled with black to brownish saddles above the midline, ventrally creamy to silvery white. First dorsal: yellowish circular spots with a brown outer rim and the third spine with a dark blotch at the posterior end. Second dorsal: ray membranes filled with a maximum of four dark yellowish oval spots with a brown outer rim in vertical rows, the gap between the spots with pale brownish comma streaks. Pectoral and pelvic fins: pale yellowish to light brownish; upper pectoral fin with vertical rows of dark spots and lower translucent. Anal fin (male): distally blackish with white bases. Branchiostegal membrane and pelvic fin base are bright yellowish. Causal fin: a series of vertical black bands flow throughout the fin, the inter-gap with yellowish spots and a blackish lower base.

Coloration (preserved specimen) (Figure 1B). Head and body paler than in fresh condition, black blotch and bars more prominent. Fins: grey to brownish. All other yellowish spots in dorsal fins faded.

Distribution and habitat. Longtail dragonet, C. gardineri is known to be distributed in the Red Sea: Djibouti, Egypt, Eritrea, Israel (Fricke, Reference Fricke1983) and the WIO: Gulf of Aden (Yemen), East Africa, Natal (South Africa) to Comoro Islands, Seychelles, Saint Brandon’s Shoals (Cargados Carajos, Mauritius), Saya de Malha Bank, and the Maldives (Fricke, Reference Fricke1983, Reference Fricke, Smith and Heemstra1986; Regan, Reference Regan1908). The above species is known to inhabit soft bottoms in marine waters at depths of 20–174 m. A single specimen was recorded for the first time from the north-eastern Arabian Sea off Gujarat, northwestern India (Figure 3), which was collected at depths of 70–110 m (S. R., pers. comm., based on information from the fishing crew).

Remarks. Callionymus gardineri can be easily differentiated from its co-generic species C. margaretae Regan 1905 and C. persicus Regan 1905 by the presence of black blotch in the distal end of the first dorsal, third spine (vs. absent in C. margaretae); preopercular spine dorsal margin, 6–12 small antrorse serrae (vs. 3–6 in C. margaretae); second dorsal fin rays, viii, 1 (vs. vii, 1 in C. margaretae); and first dorsal, first spine long filamentous (vs. non-filamentous in C. persicus).

Callionymus omanensis Fricke, Jawad, and Al-Mamry, 2014)

Oman dragonet (Figure 2A–F; Table 1)

Figure 2.

Callionymus omanensis from northwestern India, (A–C) male; (D–F) female; (A, C) fresh, (D, F) preserved, and (B, E) preopercle spine. Scale A, C, D, F = 10 mm.

Type locality: Off Salalah City, southern Oman, Western Arabian Sea, north-western Indian Ocean, depth 500 m.

Callionymus omanensis Fricke, Jawad, and Al-Mamry, 2014: 3, 1– figs. 2, 4a; Table 1

Material examined. KU/COFS/MUS/010260 (114.8 mm SL, male; Figure 2A–C), 1 ex., 24 September 2024; KU/COFS/MUS/010261 (116.5 and 122.1 mm SL, male), 2 ex., 14 October 2024; KU/COFS/MUS/010263 (113.6 mm SL, male), 1 ex., 5 November 2024; and KU/COFS/MUS/010263 (112.2 mm SL, female; Figure 2D–F), 1 ex., 5 November 2024, 20°54ʹ27″N 70°23ʹ02″E, Veraval Fishing Harbour, northwestern coast of India, collected by S. Ragul, trawled off Gujarat, Northeastern Arabian Sea.

Identification. First dorsal-fin spines IV–V (Figure 2A and D); second dorsal-fin elements viii, 1; anal-fin elements viii, 1; pectoral-fin rays ii–iii, 16–17, i = 19–20; pelvic-fin elements I, 5; caudal rays (i–ii), i, 3, ii, 2, (iii); preopercular spine formula $1\frac{2}{ - }1$. For a detailed comparison of meristic and morphometrics, see Table 1.

Body and head: Elongated body and head, ventrally flat. Male urogenital papilla long 8.3–9.6 in HL. Large eyes (2.4–2.6 in HL) with a narrow interorbital space, male 8.2–8.7 (female 9.1) in ED. Head with almost a straight nape. Body more tapering at the tail, long caudal peduncle, male 5.3–5.6 (female 6.0) in SL with the least depth, male 22.2–23.4 (female 24.9) in SL. Head, preopercular spine (long in male 11.8–12.7 in SL and short in female 14.0 in SL) with a long, main tip upcurved, smooth ventral margin; base with a single strong antrorse spine, small antrorse barb, dorsal margin with a large curved point (Figure 2B and E). Mouth small, subterminal, maxilla reaching to a vertical through origin of eye, male 4.2–4.3 (female 4.0) in HL; small upper law, male 3.3–3.4 (female 2.9) in HL.

Fins: The first dorsal fin non-filamentous, in males 4.3–4.4 in SL (female 5.7) but slightly higher than the second dorsal fin, 5.1–5.4 in SL (female 6.4). Last ray of both second dorsal and anal fin: unbranched and divided at its base.

Colouration (fresh specimen) (Figure 2A and D). Male – head and body dorsally dark to pale brownish yellow filled with black to greyish to white spots above the midline, ventrally creamy to greyish white, a bright yellowish line flows from the pectoral base to the posterior end of the caudal fin. First dorsal: yellowish distal half of first three spines, a white streaky line at the middle of the yellow portion; a large black blotch at the membrane between the third and fourth spine with a black line connecting the first to the third spine, greyish below the black blotch. Second dorsal: yellowish, nine white wavy vertical lines with black blotch at every fin ray base. Pectoral and pelvic fins: pale yellowish to light brownish with white bases; upper pectoral fin with vertical rows of dark spots and lower translucent; distal end of pelvic fin darker than the spine portion. Anal fin: distally ½ portion blackish with white bases. Caudal fin: white, the yellow line that flows through the body also flows in between the mid elongated segmented unbranched caudal fin rays, ii; the upper part with yellow and black markings in membranes; the lower part next to the mid rays a black horizontal streak flows through the fin, the rest distal lower portion translucent. Whitish, branchiostegal membrane, and thorax. Bright yellowish, cheek and pelvic fin base (connecting membrane). Female – head and body dorsally dark to pale brownish filled with black to greyish comma-shaped markings above the midline, ventrally creamy to greyish white, a bright yellowish line flows in the midline absent. First dorsal: yellowish distal half of first three spines, a white streaky line at the middle of the yellow portion; a large black blotch at the membrane between the upper and lower half, greyish below the black line. Second dorsal: yellowish, seven black to dark yellow blotches at every fin ray base, midline, and light-yellow blotches at the distal end. Pectoral and pelvic fins: pale yellowish to light brownish with pale white bases; upper pectoral fin with vertical rows of dark spots and lower almost translucent; distal end of pelvic fin darker than the spine portion. Anal fin: distally ¼ portion blackish with white bases. Caudal fin: White, the upper part with yellow markings in membranes; the lower part next to the mid rays a yellow horizontal streak flows through the fin (black in males), the rest distal lower portion translucent. Whitish brown, branchiostegal membrane, and thorax. Pale brownish, cheek and pelvic fin base (connecting membrane).

Coloration (preserved specimen) (Figure 2C and F). Head and body paler than in fresh condition, black blotch and bars more prominent. Fins black to greyish. All other yellowish portions and the mid-yellow line faded out in males.

Distribution and habitat. Oman dragonet, Callionymus omanensis is only known from the type locality off Salalah City, Southern Oman, north-western Indian Ocean (Fricke et al., Reference Fricke, Jawad and Al-Mamry2014), where it was collected from a depth of 500 m. The present study records the occurrence of C. omanensis from the north-eastern Arabian Sea, off Gujarat, northwestern India (Figure 3), collected at the least depth range of 100–150 m (S. R., pers. comm., with the fishing crew).

Figure 3.

Distribution in the Western Indian Ocean showing, Callionymus gardineri: (▲) type locality, (●) other records; (■) C. omanensis-type locality, (⋆) new record from Gujarat, India.

Remarks. Callionymus omanensis differs from its co-generic species C. africanus Kotthaus, 1977, C. bentuviai Fricke, 1981, and C. profundus Fricke and Golani, 2013 by having a sharp pointed preopercular spine (vs. comparatively a strong spine in C. profundus); absence of small points additional to small antrorse barb and main tip (vs. presence of two small points in C. africanus and C. bentuviai); plain white thorax (vs. dark grey in C. profundus); distal median filaments of caudal fin, short (vs. very long in C. bentuviai); and caudal fin dorsal half with four dark streaks even visible in preserved specimen (vs. pale, scattered dark spots in C. africanus; vs. one horizontal dark streak in C. bentuviai; and vs. pale and few dark spots in C. profundus).