(Figs 1-3, Tabs I-IV)

Comparative material

This new species is compared with Lentipes species having no enlarged lobes associated with the urogenital papillae or elongate finger like projections in males, having an urogenital papilla in both sexes that is retractable into a sheath-like groove, and having more than 17 pectoral rays. These species are Lentipes armatus Sakai & Nakamura, 1979, Lentipes venustus Allen, 2004, and Lentipes multiradiatus Allen, 2001.

Lentipes armatus. - 21 specimens from Ishigaki City, Ishigaki Island, Okinawa Prefecture, Ryukyu Islands, Japan. BLIH 1983379, male (34.2 mm SL); Ara River; 10 Jul. 1983. BLIH 1989134, male (39.0 mm SL), BLIH 1989142, female (37.4 mm SL); Ara River; 26 Aug. 1989. BLIH 1989795, 1 male, 1 female (34.0- 36.6 mm SL); Ara River; 17 Oct. 1989. BLIH 1991375, female (42.9 mm SL), BLIH 1991686, 2 females (41.4-46.9 mm SL); Ara River; 2 Jul. 1991. NSMT P.29315, paratype, male (34.9 mm SL); Arakawa River; 3 Sep. 1974. URM P3842, 5 males, 5 females (33.1-45.2 mm SL); Miyara River; 29 May 1982. URM P4533, female (41.9 mm SL); Ara River; 4 Sep. 1982. URM P4872, male (37.9 mm SL); Miyara River; 16 Sep. 1982.

Lentipes venustus. - WAM 32372.001 (paratypes) 1 male, 1 female (24.0- 28.8 mm SL); Papua New Guinea, Apatabuia River, D’Entrecasteaux Islands, Normanby Island Bunama Village, 10°07.067’S- 150°09.12’E, 30 Jan. 2003; Allen & Stevenson. MNHN, uncatalogued, 4 males, 3 females, Papua, crique Bichain 19 Oct. 2010; Keith et al. coll.

Lentipes multiradiatus. - WAM 32370.003, 1 male, 3 females (30.0-37.0 mm SL); Papua New Guinea, Awaetowa River, D’Entrecasteaux Islands, Fergusson Island, 09°30.907’S- 150°52.04’E, 27 Jan. 2003; Allen & Stevenson. WAM 32374.002, 5 males, 1 female (25.7-37.5 mm SL); Papua New Guinea, Dibuwa River, D’Entrecasteaux Islands, Normanby Island, Yeluyelua Village, 10°02.77’S- 151°14.883’E, 30 Jan. 2003; Allen.

Other comparative specimens are those cited in Lynch et al. (2013).

Material examined

Eleven specimens from Sulawesi, totalling 5 males, 6 females; size range 29.3-46.3 mm SL [36.6-55.3 mm, total length (TL)], largest male 39.0 mm SL, largest female 46.3 mm SL.

Holotype. - MZB 21473, male (34.4 mm SL), Indonesia, Sulawesi Tenggara province, Kolaka Utara regency, Wawo district, Tinukari village, Sungai Tepasa, (Sungai is a river in Bahasa Indonesia), 03°38’32.6”S- 121°05’47.3”E; 30 Jun. 2011, Hadiaty, Wowor & Sopian coll.

Paratypes. - MZB 21474, 2 males (29.3-30.9 mm SL) and 3 females (43.4-46.3 mm SL), same data as holotype. MNHN 2013-0653, 2 males (29.3-32.0 mm SL), same data as holotype. MNHN 2013-0652, 3 females (37.6-39.0 mm SL), same data as holotype.

Diagnosis

The new species has 19-20 pectoral rays, a second dorsal and anal fins I10, and 28-33 lateral scales. The urogenital papilla is retractable into a sheath-like groove and is without lobes or other expanded tissue. The male is characterised by few tricuspid teeth in the upper jaw (10-16), ctenoid scales on anterior body region strongly ossified, the base of the first dorsal fin not reaching the base of the second dorsal fin origin, and a specific body colour, with a bright red head, a red band on caudal peduncle and orange dorsal fins.

Description

The number of pectoral rays in Lentipes species are given in table I, the number of upper jaw teeth in table II, meristic counts in table III, and morphometrics expressed to the nearest whole percent of standard length in table IV. Below, the holotype counts are given first, followed in brackets if different, by paratype

Table II. - Number of upper jaw teeth in studied species of Lentipes.

counts.

First dorsal fin (D1) with six flexible spines, second dorsal fin (D2) with one flexible spine and ten segmented rays (D VI-I,10). Anal fin with one flexible spine and ten segmented rays (A I,10) and directly opposite to second dorsal fin. Base of first dorsal fin not reaching base of second dorsal fin origin in both sexes; the distance between D1 and D2 is about half the eye diameter in male; spines not filamentous in both sexes. Pelvic fins constitute a strong adhesive disc adherent to abdomen between all five rays. Pectoral fin with 19-20 rays, ventralmost 1 st or 2 nd rays simple; posterior margin slightly rounded. Caudal fin (C) with 13 branched rays.

Lateral scales (LS) 32(28-33). No difference in scale number and arrangement between sexes. They are lightly embedded and mainly cycloid in females. Generally limited to caudal peduncle, few may extend anteriorly along midline between second dorsal and anal fins; some ctenoid scales are on the anteriormost part of the flanks. Males have mainly ctenoid scales, strongly developed with prominent spines on anterior body region, and few cycloid scales on caudal peduncle. Scales in transverse backwards (TRB) series 11(11- 13) and in transverse forward series (TRF) 10(7-12). Zigzag scales (ZZ) 12(9-12). Head, breast, nape and belly without scales. Upper jaw teeth distinctly tricuspid anteriorly, males 10(10-16), females (24-32). Premaxilla in males with 3(2-6) recurved canines posterior to tricuspid teeth; females without teeth posterior to tricuspid teeth. Teeth in lower jaw recurved and canine in males 3(3-5); no teeth in females. Cephalic sensory pore system A, B, C, D, F, H, K, L, N and O; pore H & K sometimes fused. Pore D singular with all others paired (Fig. 2); oculoscapular canal divided into anterior and posterior canal between pores H and K. Some cutaneous sensory papillae present on head.

Sexual dimorphism well developed. Ctenoid scales on anterior body region strongly ossified in males, each with 3-5 prominent spines; scales on posterior part of body with fewer, but larger ctenii than those of females. Urogenital papilla in males slender and pointed distally without associated lobes or expanded tissue (Fig. 3A), urogenital papilla retractable into a sheath-like groove; female urogenital papilla rectangular in appearance (Fig. 3B) and also retractable into a sheath-like groove. Jaw length, head length and caudal peduncle length greater in males. Dorsal, caudal and anal fins longer in males.

Colour in preservation

Male. - Background of body greyish. Background of head greyish to blackish. Snout dusky. Head ventrally greyish. Lateral midline without a well-marked black subcutaneous band. All scales on flanks and caudal peduncle with black margins. Nape greyish. Caudal fin rays greyish. Dorsal and anal fins blackish, with a lighter margin. Pelvic disk without pigment. Pectoral rays greyish. Pectoral fin base greyish.

Female. - Mostly white. Head and body greyish to whitish. More or less lateral midline with a black subcutaneous band terminating as a brownish spot at caudal fin base. Above midline some dusky bars and bands may be present and dorsally few dusky square shaped saddles may be present. Blackish spot medially at base of caudal fin; may be absent in some specimens. Dorsal rays and spines whitish, membrane and rays distally without pigment. Caudal fin rays whitish, membrane and distal margin without pigment. Anal fin without pigmentation at base of rays and spine. Pelvic disc not pigmented. Pectoral rays and membrane greyish. Pectoral base whitish.

Colour in life (Fig. 1)

Male. - Background of body greyish. Background of head and snout reddish. Dorsal margin of head greyish, upper lip red. Head ventrally whitish. Lateral midline without a well-marked black subcutaneous band. All ctenoid scales on flanks and caudal peduncle with black margins.

Bright orange dorsal fins, with a blue-edged black spot in middle of membrane between first two dorsal rays of the second dorsal fin. Caudal and pectoral fins translucent. Anal fin bluish to green in the anterior part and red in the posterior part.

Female. - Colour less variable in females. Greyish to brownish with dusky markings appearing similar to that in preservation.

Distribution

Currently known only from river Tepasa, Indonesia, Sulawesi Tenggara province.

Ecology

Lentipes mekonggaensis was collected in a swift, clear high gradient stream with a rocky and boulder-strewn bottom at the edge of oil palm plantation (388 m above sea level). It is presumed to be amphidromous as the other members of the subfamily (Keith, 2003; McDowall, 2007).

Comparison

Lentipes mekkonggaensis differs from L. kaaea, L. rubrofasciatus, L. solomonensis and L. whittenorum in not having enlarged lobes associated with the urogenital papilla in males. It differs from L. adelphizonus in not having elongate finger like projections anterior to the urogenital papillae in males. From L. dimetrodon it differs in having 19-20 pectoral fin rays vs. 15-16, from L. argenteus (this paper) and L. ikeae (this paper) in having 19-20 pectoral fin rays vs. 16-17.

Lentipes mekonggaensis differs from L. armatus, L. venustus and L. multiradiatus in having, in male, the base of the first dorsal fin not reaching the base of the second dorsal fin origin vs. reaching the base of the second dorsal fin origin, and distinctive bright red colours on body. Furthermore, it differs also from L. armatus in having fewer tricuspid teeth in the upper jaw in males (10-16 vs. 18-27); from L. venustus and L. armatus in having longer preanal length (61-63 vs. 57-61/57-62% SL) and jaw length in males (14-15 vs. 12-14/13-14% SL). Finally, it differs from L. multiradiatus in having fewer scales in lateral series (28-33 vs. 33-42), and a smaller second dorsal fin length in females (28-29 vs. 30-34).

Etymology

The name of the species is derived from the name of Mekongga mountain (Sulawesi), where the specimens were caught.