Glossogobius sentaniensis, Hoese, Douglass F. & Allen, Gerald R., 2015

Hoese, Douglass F. & Allen, Gerald R., 2015, Descriptions of three new species of Glossogobius (Teleostei: Gobiidae) from New Guinea, Zootaxa 3986 (2), pp. 201-216 : 210-214

Glossogobius sentaniensis n. sp.

Sentani Goby

Figs. 2 c, 7, 8, 9, Tables 1–6

Glossogobius koragensis . — Akihito and Meguro, 1975: 139 (Lake Sentani, Irian Jaya). Glossogobius sp. 10. — Allen, 1991: 186, pl. 16, fig. 13 (New Guinea).

Holotype. WAM P.27852–004, 78.6 mm SL female, next to airport, 2°35'S, 140°32'E, 5 November 1982.

Paratypes. BLIH 1964.137, 6(94–128), Lake Sentani, about 40 km from Sakarnapura, 11 April, 1964; CAS (uncatalogued) 1(141), E. Herald, 1960; CAS-SU 40670, 7(89–123), E. Herald and E. Held, 1944–45; CAS-SU 39921, 9(34–105), E. Herald, Dec. 1944 – Jan. 1945; NMW 34255, 1(134), 1908; RMNH 28484, 3(97–144), east shore of Lake Sentani near Zoka; WAM P.31064–001, 3(40–65), northwest end of Lake, G. Allen and D. Price, 13 August 1995.

Non– type material. CAS-SU 40669, 2(95–115), dehydrated.

Diagnosis. Preoperculum without a spine. Mental fraenum indistinct, covered by sensory papillae. Mouth large; reaching to below a point between anterior pupil and mideye; jaws forming an angle of 30–35° with body axis; upper margin of upper jaw in line with mideye. Cheeks tapering. Interorbital narrow, much less than eye. Predorsal area scaled forward to eyes. Cheek naked. Operculum patch of scales dorsally. Pectoral base covered by small scales. Prepelvic area largely covered with embedded scales, sometimes with thin naked area anteriorly. Belly fully scaled. First dorsal fin with spines 2–6 extending beyond other spines when fin depressed. First dorsal fin without black spot posteriorly. Pelvic fin thin and oval, much longer than wide; reaching just short of anus. Second dorsal rays I,9; anal rays I,8; pectoral rays usually 19; longitudinal scale count 31–35; predorsal scale count 23–31; transverse scale count (TRB) 11.5–12.5; gill rakers on outer face of first arch 1+1+6–9; lower gill rakers on outer face of second arch 8–9; branched caudal rays 13–14, usually 14; vertebrae 11+16=27(4*).

Papillae. Line 1 (before nasal pore) composed of 2 rows of papillae posteriorly, one anteriorly. Line 2 (between nasal pores) composed of single row of papillae, continuous across snout. Line 5 (suborbital) composed of single row of papillae joining line 7 below anterior margin of eye. Line 6 (suborbital branch) absent. Lines 7, 9, 10 (LL cheek rows) each composed of single row of papillae, reaching to posterior end of preoperculum. Line 8 and 11 (LT row) reaching to near end of preoperculum. Line 12 (Outer POP–mandibular) composed of single row of papillae, with an arch at posterior end of jaws and continuous with papillae line posteriorly. Line 13 (Inner POP– mandibular) composed of 2 or 3 rows of papillae. Line 20 (opercular VT) composed of single row of papillae, with multiple branches ventrally. Line 21 (Upper opercular OT) composed of single row of papillae, line gently curved. Line 22 (Lower opercular OT) short and composed of single row of papillae, with several ventral branches. Several vertical papillae rows on belly. A single curved line anteriorly on most body scales (often obscure dorsally and posteriorly).

Description. Based on 31 specimens 34–144 mm SL. First dorsal spines 6(24*); gill rakers on outer face of first arch 1+6(1), 1+1+7(6), 1+1+8(5), 1+1+9(3); segmented caudal rays 9/8(16*); vertebrae 11+16(4); branched caudal rays 6/6(4), 7/6(3), 7/7(15*), 8/7(1). Counts of other meristic characters given in Tables 1–5.

Head depressed, length 33.2–36.9% SL, width 16.8–18.3% SL, depth 14.7–16.4% SL. Snout long pointed in dorsal view, concave, with notch before eye in side view; 9.8–12.4–% SL. Eye about 1.2–2.4 in snout, 7–8.3% SL in specimens less than 100 mm SL and 4.9–7.1% SL in specimens over 100 mm SL. Small bump below anterior nostril absent. Anterior nostril at end of short tube, 1–2 nostril diameters above upper lip. Posterior nostril a large pore, from eye and 1–2 anterior nostril diameters from anterior nostril and midway between upper lip and eye (young) to slightly closer to upper lip than eye (adult). Preoperculum long, distance from end of eye to upper posterior preopercular margin less than snout length. Postorbital very long, subequal to distance from tip of snout to posterior end of eye. Gill opening reaching to a point midway between posterior margin of eye and posterior preopercular margin. Teeth in upper jaw: outer row of teeth conical, slightly enlarged and wideset with smaller teeth in between larger teeth, 3–4 inner rows of smaller depressible, inwardly directed teeth, innermost row larger than middle rows. Teeth in lower jaw: teeth in outer row conical, slightly enlarged and wide-set anteriorly, 3–4 inner rows of smaller depressible teeth, teeth in innermost row larger than teeth in middle rows. Tongue tip bilobed. Gill rakers on outer face of first arch long and slender, one–third to one quarter filament length. Rakers on inner face of first arch and other arches short and denticulate. Body covered mostly with large ctenoid scales, cycloid on midpredorsal region, pectoral base, prepelvic area, operculum and belly. First dorsal fin triangular shaped, origin well behind pelvic insertion. Second dorsal fin subequal to first dorsal fin in height. Anal fin slightly lower than dorsal fins. Pectoral fin with rounded margin, reaching to above anus. Pelvic disc thin, much longer than wide, reaching just short of anus; fifth ray with 8–14 terminal tips.

Head pores. Nasal pore directly above posterior nostril, rarely with extra pore adjacent to nasal pore (often on one side only); anterior interorbital pore present posterior interorbital pore present (single or paired); a single postorbital pore behind eye; infraorbital pore below postorbital present; lateral canal pore above preoperculum present; lateral canal pore above posterior preopercular margin absent; terminal lateral canal pore above operculum present; short tube above operculum, with pore at each end present; 3 preopercular pores, upper in line with lower margin of pupil; middle pore midway between other pores.

Coloration in alcohol: Head and body dark brown, ventral surfaces light brown. A dark brown bar from anteroventral margin of eye to middle of upper jaw; posterior end of jaws light brown; a small brown spot behind eye; a short dark brown oblique bar from posteroventral margin of eye extending across cheek about half way to posterior preopercular margin; operculum with a large brown blotch anteriorly. A large brown spot (slightly larger than eye length behind upper pectoral base. A series of very large (greater than half body depth) elliptical dark brown spots on midside; first spot below first dorsal origin, second spot below second dorsal origin, third spot below posterior end of second dorsal fin, fourth on middle of caudal peduncle; small spot at end of caudal peduncle, continuous with large spot on bases of fin rays; back with large brown blotches and saddles, between and dorsal to midside spots. Leading edge of first 3 dorsal spines brown; second dorsal fin with small brown spots forming rows; anal, pectoral and pelvic fins clear, without distinct spots; caudal with small black spots forming wavy bands on upper four–fifths of fin, lower fifth of fin grey.

Coloration in life ( Fig. 8 ): Head and body tan to light brown with dark brown to blackish markings as described above for preserved specimens; Leading edge of both dorsal fins yellow; second dorsal fin with small brown spots forming rows; anal, pectoral and pelvic fins clear, without distinct spots; caudal with small black spots forming 5–6 wavy, most vivid on middle portion of fin.

Distribution. Glossogobius sentaniensis is known only from Lake Sentani, lying approximately 10 km west of Jayapura, the capital of Papua Province, Indonesia. The lake, which has a convoluted shoreline with many small inlets and larger bays, is situated at an elevation of about 80 m. It is approximately 26 km long with a maximum width of about 7 km, although the average is only 2–3 km. Boeseman (1963) provided additional details of the lake habitat. The area is now heavily populated and a major airport lies along its northern shore. Increasing pollution is a major problem as a consequence of numerous shoreline villages, the encroaching suburbs of Jayapura, and widespread deforestation. Nevertheless, the lake is still inhabited by native species. The introduction of exotic fishes including the notorious tilapia, walking catfish, snakeheads, and climbing perch has also impacted the native fish fauna, which includes two melanotaeniid species, Chilatherina sentaniensis ( Weber, 1907) and Glossolepis incisus Weber, 1907 , as well as the new Glossogobius . A brief snorkelling survey at the lake by the second author in April 2000 revealed that G. sentaniensis was relatively common, with about 50 individuals sighted during a 20- minute swim along the lake shore. The fishes were seen on both rocky and soft substrate with abundant aquatic vegetation.

Similarity to other species. Glossosogobius sentaniensis is most similar to G. aureus and G. koragensis in having a long snout and large mouth and lack of distinct mental fraenum. These species are the only species of the Glossogobius giuris complex with cheek papilla lines 5, 7, 9 and 10 composed of a single row of papillae ( Hoese & Allen, 2012) known from New Guinea. Glossosogobius sentaniensis differs from G. koragensis in having a narrower interorbital, with a single median anterior and posterior interorbital pores ( Fig. 9 ) and larger spots on the midside (versus interorbital pores paired or asymmetrical and small spots on the body). It differs from G. aureus in having larger spots on the midside and a larger head (33.2–39.6% SL versus 30.5–34.3% SL).

Etymology. Named for the type locality, Lake Sentani.

Remarks. Of the specimens examined, 20 were females (34–140 mm SL) with a rounded urogenital papilla, 8 males (40–144 mm SL) with an elongate urogenital papilla and three (34–39 mm SL) with an undifferentiated urogenital papilla.

Species in Allen 1991 Current status areas in New Guinea notes

Glossogobius aureus Glossogobius aureus Akihito and Meguro, 1975 lowland south

Glossogobius bicirrhosus Glossogobius bicirrhosus ( Weber, 1894) estuaries and lower rivers, widespread

Glossogobius biocellatus Psammogobius biocellatus ( Valenciennes, 1837) widespread Indo-west Pacific Hoese et al. 2015

Glossogobius brunnoides Glossogobius brunnoides ( Nichols, 1951) highlands near Mt Hagen under study

Glossogobius bulmeri Glossogobius bulmeri Whitley, 1959 widespread highlands north & south under study

Glossogobius celebius Glossogobius celebius ( Valenciennes, 1837) and coastal rivers west Hoese & Allen, 2012

Glossogobius celebius Glossogobius illimis Hoese & Allen, 2012 coastal rivers, north and west Hoese & Allen, 2012

Glossogobius coatesi Glossogobius coatesi Hoese & Allen, 1990 north (Sepik & Ramu rivers)

Glossogobius concavifrons Glossogobius concavifrons ( Ramsay and Ogilby, 1886) south and northern Australia

Glossogobius giuris Glossogobius giuris ( Hamilton, 1822) scattered localities north and south

Glossogobius hoesei Glossogobius hoesei Allen and Boeseman, 1982 Vogelkop Peninsula, west

Glossogobius koragensis Glossogobius koragensis Herre, 1935 Sepik and Ramu Rivers, north

Glossogobius torrentis Glossogobius torrentis Hoese & Allen, 1990 Sepik and Ramu Rivers, north

Glossogobius sp. 1— Munro's Goby Glossogobius munroi Hoese & Allen, 2012 south and northern Australia

Glossogobius sp. 2—Dwarf Goby two species involved, one also in Australia south under study

Glossogobius sp. 3—Mountain Goby highlands Karamui under study

Glossogobius sp. 4—Papillate Goby Glossogobius multipapillus , n. sp. north and east

Glossogobius sp. 5—Irian Goby poorly known juveniles only available western New Guinea

Glossogobius sp. 6—Twinspot Goby Glossogobius bulmeri southern Highlands

Glossogobius sp. 7—Robert's Goby Glossogobius robertsi Hoese & Allen, 2009 Fly River , southern New Guinea

Glossogobius sp. 8—Bluntsnout Goby 2 or 3 species involved Lake Kutubu under study

Glossogobius sp. 9—Island Goby Glossogobius clitellus Hoese & Allen, 2012 north to Philippines

Glossogobius sp. 10—Sentani Goby Glossogobius sentaniensis , n. sp. Lake Sentani, north

Glossogobius sp. 11—Fly River Goby Glossogobius muscorum Hoese & Allen, 2009 Fly River , south

Glossogobius sp. 12—Kutubu Goby as for sp. 8 Lake Kutubu under study

Glossogobius sp. 13—Bighead Goby Glossogobius macrocephalus , n.sp. south

Glossogobius sp. 14—Ramu Goby poorly known upper Ramu River, north under study Glossogobius circumspectus ( Macleay, 1883) widespread in mangroves only

Figures

FIGURE 2. Sensory papillae of three species of Glossogobius: a. Glossogobius macrocephalus, based on holotype WAMP. 26972 – 003 and paratype WAMP. 26972 – 003; b. Glossogobius multipapillus, composite based on holotype and several Paratypes; c. Glossogobius sentaniensis, based largely on holotype, WAMP. 27852 – 004.

FIGURE 8. Photo of live individual from Lake Sentani, photo G. Allen.

FIGURE 9. Head canals of Glossogobius sentaniensis and G. aureus compared to G. koragensis.