Gnatholepis ophthalmotaenia ( Bleeker, 1854 )

Larson, Helen K. & Buckle, Duncan J., 2012, A revision of the goby genus Gnatholepis Bleeker (Teleostei, Gobiidae, Gobionellinae), with description of a new species, Zootaxa 3529 (1), pp. 1-69 : 43-49

Gnatholepis ophthalmotaenia ( Bleeker, 1854)

( Figs 12E , 21–23 ; Tables 5–8, 13)

Gobius ophthalmotaenia Bleeker, 1854: 46 (Nova Selma, Cocos-Keeling Island).

Gnatholepis davaoensis Seale, 1910: 537 (Samal Island, Davao Gulf, Mindanao).— Randall and Lim 2000: 638; Randall and Greenfield 2001: 12 (Taiwan); Senou et al. 2004: 243 ( Japan).

Gnatholepis gemmeus Herre, 1927: 135 , pl. 9, fig. 3 (Samal Island, Davao Gulf, Mindanao).— Herre 1931: 14 ( New Hebrides); Herre 1935: 357–358 (Bushman Bay, Malekula Island, New Hebrides); Koumans 1940: 184.

Gnatholepis corlettei Herre, 1935: 418 (Bushman’s Bay, Malekula, New Hebrides).— Herre 1931: 14 (nomen nudum); Herre 1936: 356–357 (Bushman Bay, Malekula Island, New Hebrides); Koumans 1940: 138; Böhlke 1953: 112; Ibarra and Stewart 1987: 40.

Gnatholepis deltoides — Masuda et al. 1984: 252, plate 240Q (Yaeyama Islands).

Gnatholepis anjerensis (in part)— Randall and Greenfield 2001: 3.

Gnatholepis cf anjerensis — Kuiter and Tonozuka 2001: 671 (S of Bitung, Sulawesi).

Gnatholepis ophthalmotaenia — Kuiter and Tonozuka 2001: 672, figs A–C (Bali, Indonesia); Allen and Adrim 2003: 58 ( Flores, Ambon, Halmahera).

Gnatholepis anjerensis — Motomura et al. 2010: 213, fig. 524 (Yaku-shima Island).

Diagnosis. A moderate-sized (up to 55 mm SL) Gnatholepis with distinctive colour pattern in males of six broad vertical dark blotchy bars along mid-side of body, several staggered rows of black spots along the dorsal part of the body, one to four irregular rows of golden yellow (in life) spots along lower half of body, two characteristic small black spots at base of first dorsal fin and one to three staggered rows of oval black ocellate spots on anal fin (in life, red, blue and yellow may surround black spots), females with vertical dark body bars much paler and red and yellow markings much less distinct; second dorsal and anal fin rays nearly always I,11; pectoral rays 15–17, usually 16; lateral scales 24–30, usually 26; 9–10 predorsal scales (usually 8–9), ctenoid and cycloid.

Material Examined. COCOS-KEELING: Syntype of Gobius ophthalmotaenia, RMNH 4526, 55 mm SL male [one of 5 possible syntypes], Nova-Selma, J. Clunies-Ross. JAPAN: NSMT-P67349 , 1 (33), Hoshizuma-nohama Beach, Iriomote-jima, Yaeyama Islands , T. Mukai, 17 August 2000 ; NSMT-P64595 , 3 (22.5–29), Beguala Gnatholepis davaoensis , 52 mm SL male , BPBM 18670 , tidepool at S end of island at Hou Pi Hoo, J. Randall, A. Choi and C. Wong, 11 June 1975 ; ASIZP 59337 , 3 (39–46), Wan-li-tung, Kenting National Park , Henchuen, Pingtung County, K . T. Shao, 8 October 1985 . BPBM 38374 , 4 (27–52), same data as neotype. PHILIPPINES : AMS I.21938-003, 16(10.5–35.5), inlet 2 km S of Tambuli, Mactan Island , Cebu, D. Hoese and T. Hynes, 2 May 1980 ; AMS I.24136-001, 1(36.5), Batangas, Anilao, E. Murdy, 1 February 1980 ; AMS I.21931-004, 4(34–40), Lapu Lapu market, Cebu, Mactan Island , E. Murdy, 30 April 1980 ; AMS I.21931-007, 1(36), Lapu Lapu market, Cebu, Mactan Island , E. Murdy, 30 April 1980 ; ex-AMS I.21931-005, 2(38–42), same data as previous. INDONESIA : NSMT-P64545 , 3 (22.5–29), Baguala Bay, Ambon, K. Shibukawa, 1 December 1998 ; USNM 266393 , 1 (35.5), Kampung Pasir Putih, Jailolo district, Halmahera Island , P. Taylor, 30 April 1981 ; NSMT-P64505 , 2 (17–26.5), SE coast of Kotania Bay, Ceram, K. Shibukawa, 4 December 1998 ; NSMT-P64639 , 1 (27), Kotania Bay, Ceram, local fisherman, K. Matsuura and K. Shibukawa, 3 December 1998 ; NTM S.12697-001, 1(29), small creek at beach at Poso Harbour, Sulawesi, H. Larson and R. Williams, 5 September 1989 . PAPUA NEW GUINEA: AMS I.32492- 004, 1(29.5), mangrove at Madang, 29 November 1987 ; AMS I.32492-009, 1(26), mangrove at Madang, 29 November 1987 ; NTM S.13679-031, 1(33.5), opposite Christensen Research Institute, Nagada Harbour, Madang, H. Larson and M. Jebb, 17 October 1992 ; USNM 308210 , 21 (11.5–34), Maiwara Island , W of Alotau, Milne Bay , T. Roberts, 3 September 1975 . SOLOMON ISLANDS: AMS I.31088-002, 1(25), Lembu, New Georgia, S. Blaber, August 1988 ; CAS 51506, 23 (29–35.5), first point S of Paeu River, Vanikolo, Santa Cruz Islands , R. Bolin, 30 September 1958 ; NTM S.11328-002, 1(34), Talisondo Island , Vona Vona, S. Blaber, 9 July 1987 . VANUATU: FMNH 17367 , holotype of Gnatholepis corletti , 25 mm SL female, Bushman’s Bay, Malekula Island , New Hebrides, A.W. Herre, 4 April 1929 .

Other material; no data taken. PHILIPPINES: USNM 160804 , 34 ; CAS 51508, 8 , Dumaguete Beach , Negros Oriental ; USNM 261647 , 29 , Negros Island , Negros Oriental . INDONESIA: USNM 243456 , 2 , Ambon, Moluccas .

Description. Based on 54 specimens, 19–55 mm SL.

First dorsal VI; second dorsal I,9–I,11 (mean I,10.9); anal I,10–11 (mean I,10.9), pectoral rays 15–17 (mean 16.0), segmented caudal rays nearly always 17; caudal ray pattern nearly always 9/8; branched caudal rays 6/6 to 8/ 6 (usually 7/6); lateral scale count 24–30 (mean 26.4); TRB 9–11 (mean 9.8); predorsal scales 6–10 (mean 8.5); circumpeduncular scales 11–12 (mean 12.0). Gill rakers on outer face of first arch 1–2 + 3–5 (in 7, usually 1+4).

Body compressed, width at anus 10.9–24.4% (mean 14.0%) of SL. Body rather stocky, body depth at anus 20.9–26.9% (mean 23.9%) of SL, body depth at first dorsal fin origin 11.2–27.5% (mean 24.1%) of SL. Head compressed, broader ventrally, slightly deeper than wide, HL 25.2–30.7% (mean 28.0%) of SL; head depth at posterior preopercular margin 68.5–86.1% (mean 75.8%) of HL; head width at posterior preopercular margin 57.7–78.3% (mean 69.2%) of HL; head profile bluntly pointed to somewhat rounded; nape profile slightly curved. Mouth just terminal, fleshy snout tip slightly overhanging jaw tips, mouth slightly oblique; jaws generally reaching to below anterior margin of eye; upper jaw length 28.1–42.0% (mean 34.4%) of HL. Upper lip smooth, narrower than lower, lower lip finely papillose close to teeth, with twist or fold posteriorly, forming triangular flap, lip interrupted at chin. Eye moderate, dorsolateral, 25.0–33.9% (mean 28.8%) of HL; preorbital width 16.5–24.0% (mean 19.8%) of HL. Snout bluntly pointed, 25.3–38.3% (mean 32.2%) of HL; posterior naris round to almost triangular, adjacent to anterior margin of eye; anterior naris in short tube, higher on posterior margin of eye, at level with lower half of eye. Interorbital narrow, 6.3–11.0% (mean 8.1%) of HL. Caudal peduncle compressed, length 14.6–19.4% (mean 16.7%) of SL; caudal peduncle depth 10.9–14.0% (mean 12.1%) of SL.

First dorsal fin rounded to square, with no spines greatly elongate; first or second spine usually longest; when adpressed, spine tips reaching to first to second element of second dorsal fin. First dorsal spine length 15.5–21.8% (mean 19.2%) of SL; second dorsal spine length 15.9–22.2% (mean 18.6%) of SL; third dorsal spine length 14.5–22.7% (mean 17.8%) of SL. Second dorsal fin as tall as first dorsal fin, rays longer posteriorly, fin pointed posteriorly. Anal fin a little lower than second dorsal fin, anteriormost rays shorter than posterior rays; fin pointed posteriorly. Second dorsal and anal fin rays, when adpressed, usually reaching caudal fin in adults. Pectoral fin somewhat pointed, central rays longest, 23.3–29.0% (mean 26.4%) of SL; fin reaching back to above first few anal fin rays. Pelvic fins fused, frenum with distinctive finely fimbriate margin, fins oval, reaching back to anal fin spine, 22.2–30.0% (mean 27.4%) in SL. Caudal fin oval to rounded, 27.9–35.0% (mean 31.4%) of SL.

Gill opening restricted, extending anteriorly to lower edge of pectoral base. Gill rakers as in G. anjerensis . About one-quarter of first gill arch bound by membrane to inner face of opercle. Tongue short, tip bilobed.

Teeth in upper jaw in two to three rows across front and one row at side of jaw, outermost row teeth largest, curved (less so at side of jaw) and pointed, largest teeth at front of jaw; inner row teeth very small, sharp and evenly sized. Teeth in lower jaw in two to three rows, arranged similarly to upper jaw; posteriormost one or two outer row teeth enlarged, often recurved in males.

Ctenoid scales on predorsal area of variable extent, from just over opercle to close up to behind eyes, midline often of cycloid scales; occasionally entire predorsal covered with cycloid scales. Opercle covered with scales, usually mostly ctenoid. Preopercular scales usually cycloid, although upper or rear part of preopercle may include ctenoid scales; cycloid scales often extending anterior to vertical dark cheek-bar below eye. Breast with cycloid scales usually reaching forward to anterior of preopercular margin (below eye); scales reaching at least to below rear margin of preopercle. Pectoral fin base covered with cycloid scales. Belly scales along midline cycloid anteriorly at least; posterior half of belly midline may be of ctenoid scales.

Head pores and sensory papillae as in G. anjerensis ( Fig. 1 ).

Coloration of fresh material. Illustrations of living fish can be found in Senou et al. (2004: 243, as G. davaoensis ), Kuiter and Tonozuka (2001: 672, figs A–C) and Randall and Greenfield (2001: 9 F, G, as G. davaoensis ).

Head and body bright pearly white to yellowish white with six broad diffuse black to brown bars or rounded blotches along mid-side of body, reducing in size posteriorly, posteriormost small blotch at mid-base of caudal peduncle; often with five indistinct brown short saddles (or staggered pairs of rectangular blotches) crossing dorsum ( Fig. 21 ). Three or more irregular rows of small round black spots along dorsal third of body, often with

Predorsal and snout finely speckled with dark brown to black, opercle and cheek variably spotted with bright blue-white to pearly white spots that extend onto body, forming several rows of blue spots, these spots often arranged around each mid-lateral black blotch like an ocellus. Dark brown to black cheek-bar of variable width, from ventral edge of eye running vertically to slightly obliquely down to end on lower preopercular edge, but not extending onto branchiostegal membranes; sometimes black cheek-bar narrow and surrounded by diffuse brown to red-brown pigment. Black to very dark brown line from above middle of iris running obliquely back over top of eye. Above pectoral fin base, indistinct and diffuse brown to dull orange blotch present, partly connected to broken brown line or series of brown spots running from behind eye along top of preopercle. Pectoral fin base white with pale blue-bordered horizontal brown line or diffuse orange to light brown blotch across mid-base.

First dorsal fin translucent, with three to six rows of short oblique dusky streaks or spots, beginning of first three (or more) wavy rows marked by black spot on front of first spine and often one black spot at base of spine; two dense round black spots at base of fin, one at base of fourth spine and one at base of sixth. Second dorsal fin similar but with more rows of diffuse dark spots which may transform into darker spots and vertical streaks on membrane, especially on posterior half of fin; beginning of rows of spots marked by black spot on front of second dorsal fin spine. Anal fin brightly coloured in male: dull white to blue, with one to three staggered black ocellate oval to round spots, becoming larger and more numerous toward rear of fin; black spots surrounded by red to pink and interspersed with pale blue to yellow round to oval spots (female less colourful, with less blue and yellow spotting on all parts of body and fins) ( Figs 21–23 ). Caudal fin translucent with small red-brown blotch on midbase, and irregular rows of small black spots or diffuse light brown blotches. Pectoral fins transparent with white fin rays and fine white speckling on basal part of fin. Pelvic fins white to yellow, with pale bluish to white margin.

A photograph by Gerry Allen of a female from Madang, New Guinea, shows a very plain fish that looks like G. anjerensis but for the round orange and pale blue spots on its side, the dark spots on the anal fin and the two diagnostic black spots at the base of its first dorsal fin ( Fig. 22 ).

Coloration of preserved material. Head and body yellowish white with five somewhat indistinct brown saddles (may be split into pairs) crossing upper third of body, six vertical broad diffuse brown bars or large blotches along mid-side of body, posteriormost bar or blotch at mid-base of caudal peduncle. Three irregular rows of small round black to dark brown spots along dorsal third of body, some specimens with additional four rows of round brown spots along remainder of side of body (these spots never as dark as those in uppermost three rows).

Predorsal and snout finely speckled and spotted with brown, opercle and cheek mottled with dusky pigment. Narrow blackish cheek bar from ventral edge of eye running vertically to slightly obliquely down to end on lower preopercular edge, but not extending onto branchiostegal membranes; narrow stripe usually surrounded by diffuse brownish area. Blackish to dark brown line from above middle of iris running obliquely back over top of eye, may meet its counterpart in interorbital space. Above pectoral fin base, diffuse brownish blotch may be present, partly connected to brown line or series of brown spots running from behind eye along top of preopercle. Pectoral fin base with wavy to diffuse horizontal brown line across dorsal half, line extending onto lower part of fin and ending in small brownish blotch.

First dorsal fin transparent, with three to four wavy brown lines or series of spots, beginning at first spine; beginning of first three wavy lines marked by characteristic blackish spot on front of spine; two diagnostic dense black spots at base of fin, one at base of fourth spine and one at base of sixth. Second dorsal fin similar but with four to five rows of dark brown to blackish spots which may transform into series of darker spots and vertical streaks on membrane, especially on posterior half of fin, blackish spots becoming more intense posteriorly and proximally. Anal fin dusky, with one to three staggered rows (more rows in larger fish) of black ocellate oval spots, becoming larger and more numerous toward rear of fin. Caudal fin translucent with small brown blotch on centre of basal scale sheath, and four to five evenly spaced blackish oval spots forming vertical to curved line across fin ray bases; fin covered with irregular rows of small blackish to brown spots and streaks. Pectoral fins transparent to translucent dusky, may be finely mottled with diffuse brown in larger specimens. Pelvic fins plain dusky to almost black, may have white margin.

Distribution. Gnatholepis ophthalmotaenia has a relatively restricted distribution, being known from the Cocos- Keeling Islands, Philippines, Taiwan, southern Japan, Indonesia, New Guinea, Solomon Islands and Vanuatu.

Ecology. This species does not seem to be as common or abundant as G. anjerensis or G. cauerensis . It is found in shallow waters, from reef tidepools, among seagrass, in shallow mangroves and (usually) sand and coral rubble reef substrates at depths of 0.2– 12 m.

Comparisons. This species is easy to distinguish from all other Gnatholepis with scaled cheeks and opercles, due to the irregular rows of ocellate black spots on the anal fin (there is no equivalent present in other species), the nape scales being mostly ctenoid and the breast scales extending forward of the rear edge of the preopercle. It is a relatively small to moderate-sized species also (largest only 55 mm SL) and is sexually dichromatic (unlike Gnatholepis species other than G. argus ), with females showing much reduced patterning and intensity of colour compared to males.

Remarks. The syntypes of Gnatholepis ophthalmotaenia Bleeker are presently included in RMNH 4526, which in 1988 contained 13 specimens (29–49.5 SL), five of which are within Bleeker’s size range of 58–64 TL (he based his description on four specimens, 58–64 mm TL). The senior author’s notes state that all specimens had colouring well-preserved and that the colouring was similar to that shown and annotated for G. ophthalmotaenia in Bleeker (1983), with the “very fine black dots on upper head and back” to be added by the artist. Randall and Greenfield (2001) did not provide the basis of their synonymy of G. ophthalmotaenia with G. anjerensis and type material was apparently not examined.

The holotype of Gnatholepis davaoensis Seale, 1910 , from Samal Island, Mindanao, was listed as lost (“…. is no longer in the Bureau of Science collection”) by Herre (1927). A neotype (BPBM 18670) from Taiwan was designated by Randall and Greenfield (2001), as they considered that G. davaoensis was the correct name to apply to G. ophthalmotaenia .

The specimens identified as G. anjerensis from Yaku-shima Island, Japan, in Motomura et al. (2010) have not been examined. However, the record is placed here based on Motomura et al.’s (rather dark) Figure 524. This fish has the characteristic anal fin red and black ocellate markings of G. ophthalmotaenia and the two black spots along the base of the first dorsal are just visible.

Figures

FIGURE 1. Sensory pores and papillae in Gnatholepis anjerensis, SAIAB 2112, Mauritius, 46 mm SL male. Scales omitted.

FIGURE 12. A, Sketch of dorsal view of head of Gnatholepis caudimaculata n. sp., showing characteristic oblique mark on

FIGURE 21. Gnatholepis ophthalmotaenia male, Moalboal, Cebu, Philippines. Photo by Robert Patzner.

FIGURE 22. Gnatholepis ophthalmotaenia female, Madang, New Guinea. Photo by Gerry Allen.

FIGURE 23. Gnatholepis ophthalmotaenia female, Moalboal, Cebu, Philippines. Photo by Robert Patzner.