Schismatogobius limmoni, Keith & Delrieu-Trottin & Utama & Sauri & Busson & Nurjirana & Wowor & Dahruddin & Hubert, 2021

Keith, Philippe, Delrieu-Trottin, Erwan, Utama, Ilham V., Sauri, Sopian, Busson, Frédéric, Nurjirana, Wowor, Daisy, Dahruddin, Hadi & Hubert, Nicolas, 2021, A new species of Schismatogobius (Teleostei: Gobiidae) from Sulawesi (Indonesia), Cybium 45 (1), pp. 53-58 : 55-58

Schismatogobius limmoni , n. sp. Keith & Hubert

( Figs 1-4 ; Tab. I )

Material examined

Seven specimens from Sulawesi with a size range of 21.7-26.3 mm SL .

Holotype. – MZB.25491, male (22.2 mm SL); Sulawesi, Sulawesi Tengah, Palu , Wera Waterfall Nature Park, Indonesia, 12 Jul. 2019, Hubert et al. coll. (field number BIF 10059).

Paratypes. – MZB.25492, 4 females (21.7-26.3 mm SL) ; same data as for holotype (field numbers BIF 10050, 10058, 10060, 10061). MNHN-IC 2020-0176 , 2 females (24.7- 24.8 mm SL); same data as for holotype (field numbers BIF 10054, 10055) .

Diagnosis

A small Schismatogobius . 16-17 pectoral rays (mostly 17); pectoral fins with a medium black triangular wedge dorsally usually with 2 vertical rows of dark spots below it. First dorsal fin membrane posterior to spine 6 not connected to base of spine of second dorsal fin. Ventral surface of head in male blackish or greyish in the medium part. Frenum whitish. Ventral surface of head in female mainly whitish. Frenum whitish. A single mitochondrial lineage was observed for this species (BOLD: AEA7944).

Description

A small-sized Schismatogobius (average adult size <27 mm SL). Body naked, slender, almost circular in cross-section. Head (27.8-29.8 %SL) rounded, snout rather pointed. Mouth oblique, lower lip more prominent. Upper jaw length in male (13.5 %SL) much greater than in female (10.5-11.7 %SL); jaw length 45.5 % of HL in male (holotype) and 36.5-39% of HL in females. Lower jaw reaching vertical of 1/2 to 2/3 of the eye in female and> 2/ 3 in male. Eyes high on head, close together with interorbital width about equal to 2/3 eye diameter. Anterior nostril short and tube-like. Morphomeristic data given in table I.

Dorsal fins VI-I,8-9, membrane in first dorsal fin posterior to spine 6 not connected to base of spine of second dorsal fin. D1 with all spines about equal in length. Anal fin I,8-9, origin directly opposite to second dorsal fin origin. Caudal fin with 10-12 branched rays, posterior margin straight. Pectoral fins oblong with posterior margin rounded and 16(2)-17(5) rays, ventralmost ray unbranched. Pelvic fins always I,5, with both fins joined together on their entire length between fifth rays to form a strong cup-like disc and a well developed and lobed fraenum between spines; fins not extending beyond anus. Body depth at anus 14.1-15.2%SL, predorsal length 41.1-45.6 %SL and preanal length 62.9- 68.4 %SL.

Tongue bilobed. Teeth in upper jaw in two rows (first row 12-17), conical and slightly recurved, mostly caniniform in frontal position in male. Teeth in lower jaw in 2-3 rows (first row 12-17), all teeth conical; only outer row with slightly enlarged and somewhat recurved teeth.

Cephalic sensory pore system always with pores B, D, F, K, L, N and O, pore D singular with all other pores paired; oculoscapular canal absent between pores F and K. Anterior interorbital extension of anterior oculoscapular canal with double terminal pores B slightly posterior to posterior nostril. D pore at rear of intertobital. Posterior extension of anterior oculoscapular canal terminating laterally on each side of head at pore F, just behind posterior edge of eye. Posterior oculoscapular canal with 2 terminal pores, K and L; preopercular canal with 2 pores, N and O. Cutaneous sensory papillae not well developed.

Sexual dimorphism fairly well developed with male having jaws longer than female and a different colour pattern on ventral surface of head. Urogenital papilla oval in female and slightly pointed in male.

Colour in preservation

Five vertical black bands in dorsal view. The first one on the nape, the second one below the first dorsal fin, the third and fourth below the second dorsal fin and the fifth band at hypural crease. These bands are not uniform but with dorsal or lateral brown to greyish spots. Colour of body between each band whitish to greyish. Head and cheeks usually mottled with closely spaced black or grey spots and markings. Inferior half of lateral part of head brownish in male. Ventral surface of head in male blackish or greyish in the medium part. Fraenum whitish ( Fig. 2 ). Ventral surface of head in female whitish, lightly spotted of brown. Fraenum whitish ( Fig. 2 ). Belly whitish to greyish. First dorsal and second dorsal fins with rows of black spots on rays. Caudal fin mainly translucent with two black spots posteriorly. A black band at hypural base. Pectoral fins translucent with a medium black triangular wedge dorsally usually with 2 vertical rows of dark spots below it.

Colour in life ( Figs 3-4 )

Five vertical blackish bands in dorsal view. The first one on the nape, the second one below the first dorsal fin, the third and fourth below the second dorsal fin and the fifth band at hypural crease. These bands are not uniformly black but with dorsal or lateral greyish spots. Colour of body, on the upper part and between each band greyish with some pinkish to orange areas, particularly between the second and the third bands. On the inferior longitudinal part, the body is mottled black and grey with three aligned horizontal ovoid whitish to silvery spots on the posterior part. Head and cheeks mottled with closely spaced black or pink-orange spots and markings, and an overall shade of greyish-yellow. Sub-inferior part of head blackish. Ventral surface of head in male blackish or greyish in the medium part. Fraenum whitish. Ventral surface of head in female whitish. Fraenum whitish. Belly whitish to greyish. First and second dorsal fins with rows of black spots on rays. Caudal fin mainly translucent with two median white spots dorsally and ventrally, two black spots posteriorly and a large white spot at hypural base. Pectoral fins translucent with a medium black triangular wedge dorsally usually with 2 vertical rows of dark spots below it.

Habitat

Schismatogobius limmoni has been collected in a freshwater stream with moderate to fast flow in shallow areas of boulders, gravel and sand.

Etymology

The new species is named limmoni in dedication to Gino Limmon, from Universitas Pattimura, for all his work to improve our knowledge on Indonesian fishes and its application for the conservation of the Indonesian aquatic fauna.

Affinities

Schismatogobius limmoni differs from the other species sequenced and present in the area studied by displaying distinct mitochondrial lineages from its closest relatives and high TIM+I genetic distances to its relatives at COI gene (0.6749 to its closest relative S. sapoliensis ). It is also the second only known species of the area studied (with S. sapoliensis ) with 16-17 pectorals rays and having a broad black triangular wedge dorsally on pectoral fins. Indeed, S. saurii , S. bussoni and S. bruynisi have 14-15 pectorals rays, S. risdawatiae has 15-16 pectorals rays, and S. insignus and S. arscuttoli have 16-17 pectorals rays but the pectoral fins are striped with rows of dark spots ( Keith et al. 2017b, 2018). It differs from S. sapoliensis in having a greater jaw length/head length ratio in female (36.5-39% vs 32-36.7%), a greater jaw length in female (10.5-11.7% vs 9.1-11% SL), pectoral fins (usually 17 rays vs usually 16) with a medium black triangular wedge dorsally usually with 2 vertical rows of dark spots below it versus pectoral fins with a large transverse medium black band crossing usually all the fin, and a greater preanal length (62.9-68.4 vs 61.4-62.8) ( Tab. I ).

Distribution This species is known only from Sulawesi, Indonesia

Comparative material See Keith et al. 2017a, b and 2018.

Figures

Figure 1. – Most likely ML tree inferred using the TIM+I model (–lnL = 3711.2906, I = 0.6520, f(A) = 0.2382, f(C) = 0.3018, f(G) = 0.1692, f(T) = 0.2909, AC = GT = 1.0, AT = CG = 0.6842, AG = 12.0806, CT = 6.0413). BP are given above each branch. Schismatogobius limmoni branch is highlighted in bold.

Figure 2. – Schematic drawing of the ventral surface of head of Schismatogobius limmoni.

Figure 3. – Schismatogobius limmoni n. sp., male, holotype MZB.25491 (SL 22.2 mm; BIF 10059) (Photo N. Hubert).

Figure 4. – Schismatogobius limmoni n. sp., female, paratype in MNHN-IC 2020-0176 (SL 24.7 mm; BIF 10054) (Photo N. Hubert).