Stiphodon mele, Keith & Marquet & Pouilly, 2009

Keith, Philippe, Marquet, Gérard & Pouilly, Marc, 2009, Stiphodon mele n. sp., a new species of freshwater goby from Vanuatu and New Caledonia (Teleostei, Gobiidae, Sicydiinae), and comments about amphidromy and regional dispersion, Zoosystema 31 (3), pp. 471-483 : 473-475

Stiphodon mele n. sp.

( Fig. 1 )

TYPE MATERIAL. — Holotype: Vanuatu. Efate , Mele waterfall, 22.VII.2002, Keith and Keith coll., ♂ 27.2 mm SL ( MNHN 2008-1920 ).

Paratypes: Vanuatu. Gaua, Solomul river, 21.VII.2005, Keith, Marquet and Keith coll., 1 ♂ 21.1 mm SL ( MNHN 2008-1921) — Santo, Patunar’s Doline, 14.IX.2006, Pouilly coll., 2 ♂♂, 1 ♀ 21.1-25.3 mm SL ( MNHN 2008-1922). — Santo, Patunar resurgence, 15.IX.2006, Pouilly coll., 1 ♀ 23.8 mm SL ( MNHN 2008-1923).

New Caledonia. North Province, Panie tributary, Keith et al. coll., 1 ♂ 26.2 mm SL ( MNHN 2008-1924).

Remarks: seven specimens were collected from Vanuatu and New Caledonia totaling five males and two females with a size range of 21.1-27.2 mm SL, largest male 27.2 mm SL. All specimens caught were adults and not juveniles. The metamorphosis was finished, the males were mature (urogenital papilla well differentiated and colourful specimens parading when caught) and the female gravid.

COMPARATIVE MATERIAL. — The new species is compared in text and tables with species of nearby areas in particular Stiphodon rubromaculatus Keith & Marquet, 2007 , S. kalfatak Keith, Marquet & Watson, 2007 , S. birdsong Watson, 1996 , S. hydoreibatus Watson, 1999 , S. surrufus Watson & Kottelat, 1995 , S. tuivi Watson, 1995 , S. astilbos Ryan, 1982 and S. sapphirinus Watson, Keith & Marquet, 2005 because these have 13-14 pectoral rays and 9 segmented rays in the second dorsal fin.

Material for S. rubromaculatus , S. birdsong , S. surrufus , S. hydoreibatus , S. tuivi and S. sapphirinus is that listed in Keith & Marquet (2007), and for S. kalfatak and S. astilbos in Keith et al. (2007a).

ETYMOLOGY. — The species is named mele to honour Mele waterfall in Efate where the first specimen was found (noun in apposition).

DIAGNOSIS. — A combination of characters distinguishes Stiphodon mele n. sp. The species has 13 pectoral rays, 9 segmented rays in the second dorsal fin and 36-41 premaxillary teeth. There are no scales in predorsal midline. The most anterior scale along midline is below anterior part of second dorsal fin. Males have more and larger symphyseal teeth than females (2-4 vs. 2). The species has 3-7 scales in transverse backward series. The typical colouration of males is orange; the female is greyish to brownish.

DESCRIPTION

Number of premaxillary teeth, scale counts, and morphometrics in Stiphodon mele n. sp. and related species are given in Appendix (Tables 1; 2-5 and 6-15 respectively). Below, the holotype counts are given first followed in brackets, if different, by the paratypes counts.

Dorsal fins VI-I,9, first dorsal fin separate from and of same height as second dorsal fin; spines not elongate or filamentous. Anal fin I,10 and directly opposite to second dorsal fin. Pectoral fin counts 13 rays, uppermost rays extending beyond membrane but not appearing feathery or silky, lowermost 1 or 2 rays simple; fin oblong with posterior margin rounded. Caudal fin with 13 (13-14) branched rays, posterior margin rounded. Pelvic disc always with 1 spine and 5 stout and heavily branched segmented rays. Fifth rays joined together in their entire length forming a strong adhesive disc; disc adherent to belly between fifth rays only; between spines a strong fleshy frenum.

Scales in lateral series 14 (14-21), those on caudal peduncle are ctenoid and they become cycloid below the second dorsal fin. Most anterior scale along midline below anterior part of second dorsal fin.

Scales in transverse backward series 3 (3-7). Scales in transverse forward series 0 (0-7) with scales well developed at origin of second dorsal fin when present. Scales in zigzag series 6 (5-6). No scales in predorsal midline in males (0-1 in female). Females have a few small cycloid scales close to urogenital papilla and anus. Usually no scales on belly of males. Head, breast and pectoral base are without scales.

Premaxillary teeth 36-41, fine and tricuspid, trident I-shaped with central cusp longer than lateral cusps. Dentary symphyseal teeth in males 3 (2-4) (females, 2), conical to canine I-shaped, stronger and larger.

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

Sexual dimorphism well developed with adult males always having bright orange or greyish coloration, presence of dots on dorsal fins and longer second dorsal and anal fins than female. Urogenital papilla in males somewhat rectangular with a rounded distal tip, while in female rectangular with tiny distal fimbriate projections.

Colour in preservation

Males. Background of body pale orange or yellowish; many scales along and above midline below second dorsal fin with ctenii generally blackish; belly with few brownish pigment. Background of head orange, greyish or yellowish; occipital region with brownish pigment; preoperculum behind eye with a small yellowish patch. First dorsal fin spines with 2 to 5 blackish dots evenly spaced; second dorsal fin spines and rays with 2 or 3 blackish dots evenly spaced. Caudal fin with slightly dusky brown crescent-shaped margin posteriorly; anal fin with a thin clear distal margin, below distal margin a band of brownish pigment; pelvic disk with few brownish pigment along distal margin.

Females. Background of body yellowish; light dusky black band extending midlaterally from posterior to pectoral base ending as a spot posterior to hypural base. Another light dusky brown band extends from posterior to eye ending at upper caudal rays; belly and abdomen brownish. Background of head greyish; blackish brown band from snout and upper lip to central pectoral base. First dorsal fin clear except for fine brownish pigment along anterior and posterior edges of each spine; second dorsal fin clear, spine and rays with dusky brown pigment; caudal fin clear, rays without pigment; anal fin mostly clear; pelvic disk free of pigment; pectoral fin clear.

Colour in life

Males. Two different patterns. First one ( Fig. 1 ), generally bright orange on side of head and body. Cheeks and nose orange or yellow. Caudal fin hyaline with a reddish part at its base. The second pattern is more greyish on entire body. Posterior margin of scales blackish. All fins hyalines, some with dark dots: 2 to 5 black dots on each rays of first dorsal fin; 2 or 3 black dots on each rays of second dorsal fin.

Females. Body generally hyaline or greyish; dusky markings as in preservation. Belly whitish to yellowish.

COMPARISON

Stiphodon mele n. sp. differs from S. rubromaculatus and S. surrufus because it has more premaxillary teeth (36-41 vs. 27-32/25-36), lower scale counts in transverse back series (3-7 vs. 7-9/10-14) and in transverse forward series in males (0-1 vs. 1-4/0-12). It differs from S. sapphirinus , S. tuivi , S. hydoreibatus , S. kalfatak and S. astilbos , because it has lower scale counts (14-21 in lateral scales vs. 21-35/23-39/23- 35/30-34/24-29; 3-7 in transverse back series vs. 10-12/10-14/9-10/8-9/9; 0-7 in transverse forward series vs. 7-15/12-19/10-14/7-8/12-16). Stiphodon mele n. sp. differs from S. birdsong in having less scales in transverse back series (3-7 vs. 8-15), more premaxillary teeth (36-41 vs. generally 28-37) and a shorter caudal peduncle in length (10-16 vs. 17-23).

DISTRIBUTION

Known from rivers of Gaua, Efate and Santo in Vanuatu, Mont Panié tributaries and Bélep Islands in New Caledonia.

ECOLOGY

Like other Sicydiinae , Stiphodon mele n. sp. is found in clear, high gradient streams with rocky bottom. It lives mainly on the riverbed, on top of rocks but it is also seen swimming in open water in the current between rocks or in large pools. This species was observed from 10 to 100 m high in altitude.

Figures

FIG. 1. — Stiphodon mele n. sp., holotype ♂ 27.2 mm SL (MNHN 2008-1920), Efate, Mele waterfall, 22.VII.2002, Vanuatu, Keith and Keith coll. Photo: É. Vigneux.