Diplogrammus Gill, 1865

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 : 2422-2425

Genus Diplogrammus Gill, 1865

Diplogrammus Gill, 1865: 143 , footnote (type species: Callionymus goramensis Bleeker, 1858 by monotypy). Smith 1963: 550. Fricke 1982: 71. Fricke and Zaiser 1982: 253. Nakabo 1982: 97 (part: Indo-Pacific species). Nakabo 1983a: 11 (part: Indo-Pacific species). Fricke 1983a: 493 (revision). Nakabo 1983b: 429. Dor 1984: 236 (checklist). Houde 1984: 637. Fricke 2001: 3550. Fricke 2002: 46 (checklist). Golani and Bogorodsky 2010: 45 (checklist). Iwatsubo and Motomura 2010: 69.

Diagnosis

Body elongate and depressed. Eyes of moderate size, situated close together. No supraorbital tentacle present. Jaws with many villiform teeth. Maxillary in the male without a knob-like protuberance. Lower lip without papillae. Preopercular spine with an upcurved or straight main tip, several curved spinules at its dorsal margin, a smooth ventral margin, and one or two antrorse spinules at its base. Free opercular flap of skin present in adults (except Diplogrammus gruveli ). Lateral line along the side of the body single, but may bear dorsal and/or ventral branches; no commissure dorsally across caudal peduncle. Ventrolateral fold of skin along the sides of the body present, continuous. Two dorsal fins, the first consisting of slender and flexible spines, the second of soft rays. Rays of second dorsal and anal fins unbranched except the last which may be branched and is divided at its base.

Osteological characters (see Nakabo 1983a): cranium and body depressed. Tip of premaxillary half rounded. Lower jaw moderately depressed. Sesamoid articulars slightly curved. Anterior dorsal edge of middle ramus of urohyal laterally expands with a spoon-like shape; middle ramus longer than ventral ramus. Third branchiostegal ray attached to abaxial intermediate between ceratohyal and epihyal. Soft retrorse spine at posterior end of opercle not filamentous. Soft upward spine on preopercle bearing a filament.

Remarks

The genus Diplogrammus includes seven species which are distributed in the Indo-West Pacific including the Red Sea. Species of Diplogrammus live in shallow water on sand or coral rubble bottom, often in the vicinity of coral or rocky reefs ( Diplogrammus gruveli on open sand bottoms).

Nakabo (1982: 80) included the West Atlantic species Chalinops pauciradiatus ( Gill, 1865) in Diplogrammus . We follow Fricke (1986a: 154–155) and Fricke (2002: 45–46) in retaining a separate genus Chalinops Smith, 1963 , which is distinguished from Diplogrammus (among other characters) by having fewer soft rays in the second dorsal and anal fins, and by lacking an antrorse point at the base of the preopercular spine. Another similar genus, Protogrammus Fricke, 1985 [based on P. sousai ( Maul 1972) from the north-eastern Atlantic and P. antipodus Fricke, 2006 from the south-western Pacific], differs in having a partially free opercular flap of skin which is connected with the body in its upper half, and a ventrolateral fold of skin consisting of few, disconnected segments; an antrorse point at the base of the preopercular spine may or may not be present.

The distribution of the Red Sea species of the genus Diplogrammus is shown in Figure 1 .

Key to species of the genus Diplogrammus of the Red Sea and the western Indian Ocean

1a. Opercle with a free flap of skin ........................................................................ 2

1b. Opercle without a free flap of skin [Gulf of Suez and Suez Canal] ... D. gruveli

2a. Dorsal margin of preopercular spine with 3 or 4 curved spinules (additional to main tip) ........................................................................................................... 3

2b. Dorsal margin of preopercular spine with 5–9 curved spinules (additional to main tip) .................................................................................................................... 5

3a. Main tip of preopercular spine nearly straight; first spine of first dorsal fin in male barely filamentous, subequal to first ray of second dorsal fin [Gulf of Suez and Gulf of Aqaba] ................................................................................... D. randalli

3b. Main tip of preopercular spine upcurved; first spine of first dorsal fin in male longer than first ray of second dorsal fin ......................................................... 4

4a. Second spine of first dorsal fin in male subequal in length to first and third spines, or longer than first spine; anal fin in male pale with a black streak near outer margin of each membrane, in female plain black; caudal fin rounded [Gulf and southern Arabian Peninsula ] ............................................................ D. pygmaeus

4b. First spine of first dorsal fin in male longer than second and third spines; anal fin in male with outer one-third black, in female pale with black streak at margin on each membrane; caudal fin pointed in both sexes [central and southern Red Sea, Saudi Arabia] ...................................................................... D. paucispinis n. sp.

5a. First spine of first dorsal fin in male strongly filamentous, significantly longer than first ray of second dorsal fin; main point of preopercular spine upcurved; anal fin pale in female; head and body in male with numerous blue spots and streaks [southern Sinai to southern Red Sea, East Africa and islands of western Indian Ocean ] ................................................................................... D. infulatus

5b. First spine of first dorsal fin in male barely filamentous, not much longer than first ray of second dorsal fin; main point of preopercular point straight; anal fin in female with narrow black streak near outer margin; head and body in male with irregular brown and white spots, but without blue spots and streaks [Gulf of Suez and Gulf of Aqaba] ................................................................... D. randalli

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.