Stiphodon ornatus Meinken, 1974

Maeda, Ken & Tan, Heok Hui, 2013, Review Of Stiphodon (Gobiidae: Sicydiinae) From Western Sumatra, With Description Of A New Species, Raffles Bulletin of Zoology 61 (2), pp. 749-761 : 750-752

Stiphodon ornatus Meinken, 1974

( Figs. 1–4 ; Tables 1, 2)

Stiphodon elegans ornatus Meinken, 1974: 87 (type locality: Barung

Belantai, West Sumatra Province, Indonesia; syntypes lost) Stiphdon ornatus Meinken, 1974 : Watson, 1994: 88

Material examined. — West Sumatra Province (12 males, 10 females): ZRC 46620 (5 males, 44.9–50.6 mm SL; 6 females, 45.0– 51.8 mm SL), aquarium trade in Singapore (from Padang), donated by P. Yap, 19 Sep.2001 ; ZRC 51821 (4 males, 38.8–52.5 mm SL; 3 females, 40.3–48.4 mm SL), South Painan , donated by T. Sim , Sep.2004 ; ZRC 54113 (3 males, 34.9–38.8 mm SL; 1 female, 38.0 mm SL), Persasa Painan, coll. H. H. Tan from local fish collectors, 21 Jul.1997 . Aceh Province (2 males, 3 females) : ZRC 54181 (1 male, 37.4 mm SL; 1 female, 42.5 mm SL), Air Dingin, Tapaktuan, Aceh Selatan, coll . T. Sim et al., Apr.2009 ; ZRC 54182 (1 male, 35.0 mm SL; 2 females, 37.2, 39.4 mm SL), Desa Madat, Tapaktuan, Aceh Selatan, coll . T. Sim et al., Apr.2009 .

Diagnosis. — Number of soft-rays in second dorsal fin usually 9, pectoral fin usually 15; male having pointed first dorsal fin with elongate spines 3–5; male having large caudal fin (caudal-fin length 29–35% of SL); number of premaxillary teeth 33–45 in <50.0 mm SL; 44–47 in ≥ 50.0 mm SL; male lacking white patch behind pectoral-fin base; nape and posterior half of occipital region always covered by cycloid scales in both sexes. Male usually with 7–11 obscure dusky transverse bars laterally on posterior half of trunk and tail; male sometimes with two broad dusky bars laterally below first and second dorsal-fin bases. Number of black spots on longest pectoral-fin ray 6–12 in male, 0–6 in female.

Description. — Morphometric measurements are given in Table 1. Body elongate, cylindrical anteriorly and somewhat compressed posteriorly. Head somewhat depressed with a round snout protruding beyond upper lip. Anterior nostril short tubular, posterior nostril not tubular. Mouth inferior with upper jaw projecting beyond lower jaw. Upper lip thick with small, medial cleft and faintly crenulated with tiny fimbriate projections. Premaxillary teeth 33–47, fine and tricuspid. Dentary with 1–5 canine-like symphyseal teeth in male, none (n = 5) or with 1 smaller canine-like symphyseal tooth (n = 5) in female; dentary also with a row of unicuspid horizontal teeth (34–50) enclosed in a fleshy sheath. Larger fish having more premaxillary and horizontal teeth ( Fig. 1 ). Urogenital papilla in both sexes rectangular or rounded with one small projection at both corners of posterior edge.

Dorsal fins VI-I, 9 (n = 21) or VI-I, 10 (n = 1); first dorsal fin in female almost semicircular and usually spine 3 longest; first dorsal fin in male forming parallelogram with spines 3–5 elongate (usually spine 4 longest) but not filamentous, most posterior points of first dorsal fin (tip of spine 4 or 5) extending to base of soft-rays 2–5 of second dorsal fin when depressed. Anal fin I, 9 (n = 1) or I, 10 (n = 21), below second dorsal fin. In female, anterior rays (usually softray 2 or 3) longest in second dorsal and anal fins; in male, posterior rays longer than anterior rays (last and/or next to last rays longest). Caudal fin with 12 (n = 1 with damaged rays), 13 (n = 18) or 14 (n = 3) branched rays within 16 (n = 1) or 17 (n=21) segmented rays, posterior margin rounded or somewhat truncated, male with larger fin than female (caudal-fin length 29–35% of SL in male, 24–27% of SL in female). Pectoral fin with 14 (n = 1), 15 (n = 19), or 16 (n = 2) rays. Pelvic fin I, 5, paired fins joined together to form a strong cup-like disk with fleshy frenum.

Scales in longitudinal row 29–33 ( Table 2); scales in transverse row 10 (n = 2), 11 (n = 20); scales in transverse row in caudal peduncle 9. Nape and posterior half of occipital region always covered by cycloid scales; most anterior dorsalscale slightly exceeding middle of occipital region ( Fig. 2 ). Ctenoid scales covering almost entire tail and trunk, but belly covered by cycloid scales. Pectoral-fin base naked. Cycloid scales occurring along first and second dorsal- and anal-fin bases and on proximal part of caudal fin; some scales on most anterior part of lateral sides of trunk (behind pectoralfin base) and a few scales along dorsal and ventral midlines on posterior part of caudal peduncle sometimes cycloid.

Cephalic sensory pore system always A, B, C, D, F, H, K, L, N, and O; pore D singular, all others paired ( Fig. 3 ). Oculoscapular canal separated into anterior and posterior canals between pores H and K. Cutaneous sensory papillae developed over lateral and dorsal surface of head ( Fig. 3 ).

Colour in preservation. — Sexual dichromatism well developed.

Males ( Fig. 4a–c ). Background of body and head brown or pale brown; 7–11 obscure dusky transverse bars regularly arranged laterally on posterior half of trunk and tail, but these bars often indistinct; some males with two broad dusky bars laterally below first and second dorsal-fin bases, and with pale brown gap between those two dusky bars and on caudal peduncle (possibly nuptial colour); lateral sides of head and pectoral-fin base blackish. First dorsal-fin membranes grey or blackish, spine 1 with 0–6 black spots, other spines usually entirely blackish without spot. Second dorsal fin dusky with 1–7 whitish spots on spine and each soft-ray or totally blackish. Anal fin dusky or blackish sometimes with translucent narrow margin. Caudal fin pale grey or brown with black spots on central 6–10 rays forming 7–12 black transverse stripes or fin totally blackish; dorsal margin of fin transparent. Pectoral-fin membranes transparent; almost all rays, except ventral 1–2 rays, with distinct black spots distributed over almost entire rays, translucent or whitish between each black spot; number of spots on longest rays (usually rays 7 and/or 8) 8–12, size of each spot similar or smaller than intervals ( Fig. 4a, b ), but one male having small number (6 on longest ray) of larger spots ( Fig. 4c ). Middle to proximal part of pelvic-fin rays, fin membranes, and frenum dusky or blackish, distal margin translucent except for around soft-ray 5, which has dusky edge. Blackish fins probably nuptial colour.

Females ( Fig. 4d, f ). Background of body and head cream; black longitudinal band extending from snout to below eye and to middle of pectoral-fin base, band continuing from behind pectoral-fin base to posterior end of caudal peduncle through lateral midline, this band sometimes composed of 8–9 obscure black regular spaced blotches on caudal region. Dorsal part of upper lip black. Small black pigments along anal-fin base and ventral midline of caudal peduncle. Another black longitudinal band from just behind eye extending dorsolaterally to base of upper procurrent caudal-fin rays. Dorsum between upper lateral bands brown sometimes with 0–2 and 5 obscure cream blotches on trunk and tail, respectively. Snout with U-shaped black band connecting both eyes; irregular black markings scattered between eyes. First dorsal-fin membranes transparent, spine 1 sometimes with 1–3 black spots, other spines usually dusky without clear markings, but sometimes with 1–4 black spots. Second dorsal-fin spine and soft-rays often with 1–4 black spots, membranes mostly transparent. Anal fin usually without remarkable pigments, but one female having dusky anal fin with transparent margin ( Fig. 4e ). Black blotch at centre of proximal part of caudal fin; caudal-fin rays usually with black spots, forming 3–7 transverse bars on some central rays, membranes mostly transparent. Black lateral band on pectoral-fin base often spreading to proximal part around rays 5–7 of pectoral fin; pectoral fin usually with 1–6 black spots on central rays, but sometimes lacking black spot; membranes transparent. Pelvic fin translucent without pigment.

Distribution. — All specimens of S. ornatus observed in the present study were collected from West Sumatra Province and the southern part of Aceh Province, Sumatra. The specimens reported in Meinken (1974) and Watson (1994, 1998, 2008) were collected from West Sumatra Province. Aceh population extends the range of this species northwards from West Sumatra Province.

Remarks. — Stiphodon ornatus closely resembles several congeners (viz. S. atratus Watson, 1996 , S. imperiorientis Watson & Chen, 1998 , S. martenstyni Watson, 1998 , S. pelewensis Herre, 1936 , S. pulchellus (Herre, 1927) , S. weberi Watson, Allen & Kottelat, 1998 ) in fin-ray and tooth counts, first dorsal-fin shape in male, and general colouration. Although caudal-fin length of S. ornatus male (29–35% of SL, mean 31% of SL) was larger than those of the other species ( S. atratus , 20–28% of SL in Watson et al., 1998; S. imperiorientis , 23–29% of SL in Maeda et al., 2012b; S. martenstyni , 24% of SL in Watson, 1998; S. pelewensis , 25–27% of SL in Herre, 1936 and Suzuki et al., 2010; S. pulchellus , 23–29% of SL in Maeda et al., 2012b; S. weberi , 20–25% of SL in Watson et al., 1998), comprehensive and exhaustive studies are required to elucidate the differences in their morphology and to understand phylogeny of this genus.

Figures

Fig. 1. Number of premaxillary and horizontal dentary teeth of Stiphodon ornatus (triangles), S. semoni (squares), and S. maculidorsalis (circles) fromWest Sumatra and Bengkulu Provinces, Sumatra. Solid and open symbols represent males and females, respectively.

Fig. 2. Dorsal scalation on head and nape in Stiphodon ornatus: a, male (50.1 mm SL, ZRC 46620); b, female (45.0 mm SL, ZRC 46620).

Fig. 3. Diagrammatic illustration of head showing arrangement of the cephalic sensory pores and cutaneous sensory papillae in Stiphodon ornatus (50.1 mm SL, ZRC 46620): a, dorsal view; b, lateral view; c, ventral view.

Fig. 4. Stiphodon ornatus: a, male, 45.1 mm SL (ZRC 46620); b, male, 52.5 mm SL (ZRC 51821); c, male, 38.8 mm SL (ZRC 51821); d, female, 46.9 mm SL (ZRC 46620); e, female, 40.3 mm SL (ZRC 52821).