Sicyopterus squamosissimus, Keith & Lord & Busson & Sauri & Hubert & Hadiaty, 2015

Keith, Philippe, Clara, Lord, Busson, Frédéric, Sauri, Sopian, Hubert, Nicolas & Hadiaty, Renny K., 2015, A new species of Sicyopterus (Gobiidae) from Indonesia, Cybium 39 (4), pp. 243-248 : 244-247

Sicyopterus squamosissimus n. sp.

( Figs 1-3 , Tabs I-IV)

Comparative material

Sicyopterus squamosissimus n. sp. is compared to the two known valid species with two lateral clefts on a crenulated upper lip and a second dorsal fin with one spine and 10 segmented rays: Sicyopterus longifilis de Beaufort, 1912 and Sicyopterus calliochromus Keith, Allen & Lord, 2012 .

Sicyopterus longifilis de Beaufort, 1912 . – Syntypes: ZMA 112562, 2 males, size range 36.7-74.5 mm SL. Upper course of Tubah River, western Ceram, Indonesia. WAM 31041-007, 3 males, 3 females, size range 48.4-62.5 mm SL. Yapen Island , Reifafeif River, Papua Province, Indonesia . WAM 31034-005, 1 male, 2 females, size range 66.7-70 mm SL. Yapen Island , Reifafeif River, Papua Province, Indonesia .

Sicyopterus calliochromus Keith, Allen & Lord, 2012 . – Holotype: MZB 20009, male, 55 mm SL. Tirawiwa River , 132 km from mouth, Papua; 4 Apr. 1998; G.R. Allen and S. Renyaan coll. Paratypes: WAM P31447.004, 4 males, 1 female, size range 47.1- 58.2 mm SL. Same data as holotype; MNHN 2011-0042, 2 males, 1 female, size range 50.3-55.6 mm SL. Same data as holotype .

Material examined

Nine specimens from streams of Sumatra and Java, Indonesia, totalling five males and four females, size range 33.7- 51.4 mm SL.

Holotype. – MZB 22716 male, 42.8 mm SL. Kabupaten Sukabumi , Citiis, West Java, Indonesia; 11 Dec. 2013; Hubert, Busson, Sauri coll.; BIF1688.

Paratypes. – MZB 22717, 1 female, 51.4 mm SL. Same data as holotype ; BIF1689. MNHN 2014-148, 1 female 50.5 mm SL. Same data as holotype ; BIF1684. MNHN 2014-149, 4 males, 2 females, 33.7-45 mm SL. Palembang , Sumatra, Indonesia; Apr. 2013; M. Negrini coll.

Diagnosis

A Sicyopterus with two lateral clefts on crenulated upper lip, a second dorsal fin with one spine and 10 segmented rays. Second and third rays of the first dorsal fin filamentous, 61-66 lateral scales, 21-26 predorsal scales and 17-22 transverse back scales; a reddish caudal fin in male with a slight blue line on the upper and lower parts.

Description

Scale counts are given in table I, morphometrics in table II and fin length in tables III and IV. Below, the holotype counts are given first, followed, in brackets if different, by the paratype counts.

Dorsal fins VI-I,10; first dorsal fin with the second and third rays longest, without membrane, in males usually reaching third or half of the second dorsal fin base. Anal fin I,10 directly opposite second dorsal fin. Caudal fin with 13-14 branched rays and posterior margin rounded. Pelvic disk with one spine and five branched rays on each side, fifth rays joined together over their entire length, a thick frenum between spines; disc adherent to belly between all five rays. Pectoral fins 18-20, posterior margin rounded. LS 61 (61- 66), ctenoid scales on flanks and caudal peduncle. TRB 19 (17-22). TRF 22 (16-23). PD usually 21 (21-26). ZZ 16 (15- 17). Belly entirely covered with cycloid scales, extending from anus, almost to pelvic base. Nape with cycloid scales. Upper jaw with a single row of flexible tricuspid teeth, lateral cusps rounded, medial cusps shorter than lateral cusps. Dentary with a single straight row of conical teeth 5 (1-6) on each side, not curved and not meeting at symphysis; anterior teeth usually caniniform; horizontal teeth correspond in position with upper jaw teeth. Upper lip crenulated and with two lateral clefts. Crenulae irregular, generally small and shallow, with the exception of 4-5 on each side. Lower lip mostly absent, rudimentary elements present as expanded and folded tissue posterior to lower jaw teeth. Cephalic sensory pore system A, B, C, D, F, H, L, (M), (N) and O (M and/or N sometimes missing). Pore D single with all others paired. Oculoscapular canal uninterrupted posterior to eye. Cutaneous sensory papillae developed on head ( Fig. 2 ).

Males with an elongate urogenital papilla in appearance with distal tip rounded. Females with bulbous bilobed urogenital papilla ( Fig. 3 ).

Colour of preserved specimens

Sexual dichromatism not developed. Specimens usually brownish to greyish on the head and the back. The flanks are yellowish to brownish with sometimes a slightly longitudinal brownish band from snout to hypural base or with five-six dusky to brownish saddles on dorsum. The snout is black. Caudal fin greyish. Pelvic fins whitish to greyish. First dorsal fin greyish. Second dorsal fin greyish to brownish. Pectoral fin usually greyish.

Colour in life

Males are often brownish to greyish usually with five-six dark saddle bars (often Y or V shaped) between head and tail ( Fig. 1A ). Cheeks and head greyish to brownish with one to three purple lines. One distinct elongated black blotch under each eye. Belly whitish to greyish. The first dorsal fin is translucent to yellowish; elongated rays bluish. The second dorsal fin is greyish to translucent and is slightly punctuated. The caudal fin is reddish in the central part, surrounded by a slightly blue line on the upper and lower parts. A black spot is present at the base of the caudal peduncle. Pectoral and anal fins translucent to yellowish. The female ( Fig. 1B ) is duller, the body is brown to yellow and the back may have five-six, more or less distinct, brown transverse small bars (V shaped). The first dorsal fin is greyish to translucent. The second dorsal fin is greyish to translucent and is slightly punctuated. The anal fin is yellowish to translucent. The caudal fin is transluscent to bluish in the central part and is surrounded by a slight blue line on the upper and lower parts.

Ecology

Sicyopterus squamosissimus n. sp. was collected in small, rapid and boulder-strewn mountain streams with rocky bottoms with two other Sicydiinae , Sicyopterus lagocephalus (Pallas, 1770) and Stiphodon semoni Weber, 1895 . It is assumed to be amphidromous as are the other members of the subfamily ( Keith, 2003; Keith and Lord 2011b).

Distribution

Currently known from Palembang, South Sumatra Province and Kabupaten Sukabumi, West Java ( Indonesia).

Etymology

The name of the species refers to the high numbers of scales compared to its congeners having two lateral clefts on crenulated upper lip, a second dorsal fin I10 and second and third rays of the first dorsal fin filamentous.

Comparison

Only two other species are known with two lateral clefts on a crenulated upper lip and a second dorsal fin count of I10, Sicyopterus squamosissimus n. sp. thus differs from S. longifilis and S. calliochromus in having more scales in LS (61-66 versus 52-58/51-56), in PD (21-26 versus 18-21/10- 16), and in TRB (17-22 versus 14-18/14-17).

Figures

Figure 1. - A: Sicyopterus squamosissimus, n. sp, holotype MZB 22716, male (BIF 1688); West Java, Indonesia; B: Sicyopterus squamosissimus, n. sp, paratype MZB 22717, female (BIF 1689); West Java, Indonesia. (Photos N. Hubert).

Figure 2. - Diagrammatic illustration of head in Sicyopterus squamosissimus showing cephalic sensory pore system and cutaneous sensory papillae. A: Dorsal view; B: Lateral view; C: Ventral view.

Figure 3. - Diagrammatic illustration of urogenital papilla in Sicyopterus squamosissimus (ventral view). 1: anus; 2: urogenital papilla; 3: anal fin. A: Male; B: Female.