Gnatholepis cauerensis ( Bleeker, 1853 )

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 : 29-39

Gnatholepis cauerensis ( Bleeker, 1853)

( Figs 4C–D , 12C , 13–18 ; Tables 5–8, 11)

Gobius cauerensis Bleeker, 1853: 269 (Cauer, Sumatra, Indonesia).

? Gobius knighti — Aoyagi 1957: 228 (Japanese Archipelago).

Acentrogobius cauerensis — Palmer 1970: 227–228 (Betio, Tarawa); Goren 1979: 18 ( Israel, Egypt, Eritrea, Ethiopia; Red Sea).

Gnatholepis cauerensis — Hoese and Winterbottom 1979: 4 ( South Africa); Goren 1981: 98 ( New Caledonia); (in part) Maugé 1986: 369 (Transkei northwards); Allen and Smith-Vaniz 1994: 16 (Cocos (Keeling)); Myers 1999: 255, plate 161E ( Micronesia); Randall 1999: 26 ( Pitcairn Island); Larson in Randall and Lim 2000: 637 (South China Sea); Randall and Earle 2000: 19 (Marquesas); Randall and Greenfield 2001: 6; Hutchins 2001: 43 (Western Australia); Larson and Murdy 2001: 3601; Kuiter and Tonozuka 2001: 673, figs A–C (Bali); Myers and Donaldson 2003: 638 ( Guam); Allen and Adrim 2003: 58 (Papua to Sumatra); Galzin et al. 2002: 232 (Rapa); Manilo and Bogorodsky 2003: S118; Randall et al. 2004: 27 ( Tonga); Lobel and Lobel 2004: 76 ( Wake Atoll); Heemstra et al. 2004: 3329 (Rodrigues); Anderson 2005: 97 ( Maldives); Hoese and Larson 2006: 1654; Williams et al. 2006: 259 (Wallis Islands); Fricke et al. 2009: 101.

Gnatholepis anjerensis —Dor 1984: 237 (Red Sea); Randall et al. 1985: 70 (Johnston Island); Randall et al. 1990b: 33, fig. 43 (Rapa).

Gnatholepis scapulostigma Herre, 1953: 193 (Engebi Island, Eniwetok [Eniwetak] Atoll, Marshall Islands).—Yoshino in Masuda et al. 1984: 252 (Ryukyu and Ogasawara Islands); Randall and Randall 1987: 309 (Enewatak Atoll); Randall et al. 1990a: 402; Myers 1991: 238, 240, pl. 124B); Randall and Goren 1993: 13 ( Maldives); Kuiter 1993: 347 (New South Wales); Allen 1997: 216; Kulbicki and Williams 1997: 22 (Ouvéa Atoll, New Caledonia); Fricke 1999: 513 (Réunion); Laboute and Grandperrin 2000: 411 ( New Caledonia); Larson and Murdy 2001: 3601; Kuiter and Tonozuka 2001: 673, figs A–C (Maumere, Flores); Nakabo 2002: 1212; Hayashi and Shiratori 2003: 97.

Gnatholepis inconsequens Whitley, 1958: 44 (Heron Island, Capricorn Group, Queensland).— Allen and Swainston 1988: 134

(Rottnest Island); Gill and Reader 1992: 223 (Middleton and Elizabeth Reefs); Francis 1993:167 (Lord Howe Island); Larson and Murdy 2001: 3601.

Gnatholepis cauerensis hawaiiensis Randall and Greenfield, 2001: 10 , pl. IIC, D (Pukukea, Oahu, Hawaiian

Islands).— Greenfield and Randall 2004: 526–528 (Hawaiian Islands). Gnatholepis sp. — Wass 1984: 28 ( Samoa); Myers 1991:240, pl. 124C). Coryphopterus — Lobel 2003: 113 ( Johnston Atoll) [pasted-in errata sheet on inside back cover says Gnatholepis anjerensis ]. Gnatholepis cauerensis cauerensis — Senou et al. 2004: 242; Lobel and Lobel 2004: 76 ( Wake Atoll); Motomura et al. 2010:

213, fig. 525 (Yaku–shima Island). Gnatholepis australis — Randall 2009: 180, fig. 3. Gnatholepis hawaiiensis — Randall 2009: 181.

Diagnosis. A moderate-sized Gnatholepis (up to 56 mm SL) with wide range in live colour pattern; ctenoid body scales usually reaching rear corner of opercle, occasionally ctenoid scales reaching to above rear preopercular margin; nape midline scales always cycloid, distinct flap present at end of lower lip; when alive, colour variable: body translucent white with five to seven rows of small variably coloured (dull orange, brown, red-brown to blackish) spots and/or thin lines and about six indistinct diffuse orange-brown to purple-brown blotches along midside; narrow vertical black mark on top of each eye, marks may join each other across interorbital space, and narrow black vertical line crossing cheek below eye; small dark mark of variable shape (often W-shaped) above pectoral fin base, with small yellow spot in centre; second dorsal and anal fin rays usually I,11; pectoral rays 12–18, modally 16; lateral scales 24–30, modally 27; 7–12 predorsal scales (modally 9).

Material examined. SOUTH AFRICA: SAIAB 62111 , 4 (30–43), “ Tiger Cove ”, Aliwal Shoal, Kwa-Zulu Natal, 7 March 2000 ; SAIAB 60280 , 1 (46), Aliwal Shoal , Kwa-Zulu Natal, 23 April 1999 ; SAIAB 70985 , 1 (45), Manta Point , Aliwal Shoal , Kwa-Zulu Natal, 21 May 2002 ; SAIAB 73710 , 7 (16–40.5), Manta Point, Aliwal Shoal , Kwa-Zulu Natal, P. Heemstra, S. Warren, J. Stapley, 22 May 2002 ; SAIAB 64645 , 3 (39–45), Sodwana Bay , Kwa- Zulu Natal, 13 May 2001 ; SAIAB 69344 , 3 (27–40), Three-mile Reef, Sodwana Bay , Kwa-Zulu Natal, 16 May 2002 ; SAIAB 56561 , 2 (43–49), deep sponge reef, Sodwana Bay , Kwa-Zulu Natal, 12 August 1997 ; SAIAB 58554 , 3 (26.5–36.5), “ The Hospital ”, Aliwal Shoal, Kwa-Zulu Natal, 14 June 1998 ; NTM S.14694-001, 1(32), “The Hospital” reef, Aliwal Shoal , Kwa-Zulu Natal, P. Heemstra and party, 8 February 1998 . RODRIGUES: SAIAB Ko Ming , Similan Islands, 14 February 1979 . INDONESIA: RMNH 4523 , holotype of Gobius cauerensis , 1(31.5), Kauer , Sumatra, P. Bleeker, 1852-54 ; NSMT P.70196, 3(13–35), off NW coast Air Island , Lombok, K. Matsuura, 3 February 1994 ; NSMT P.70407, 2(25–29.5), Gerupuk , Lombok, K. Matsuura, 7 February 1994 ; USNM 210157 , 45 (13–33), E shore Piru Bay , Tandjung Liang, Ceram , V. G. Springer and M. Gomon, 10 January 1973 . TAIWAN: ASIZP P.56809, 3(38–39), Tauzuwan, S.C. Lee, 25 May 1987 ; USNM 327456 , 22 (26.5–52), SW shore just off Chuan-fan-Shi , V.G. Springer and party, 30 April 1968 . JAPAN: AMS I.23492-015, 1(34.5), tidepools below airport, Miyake-jima, D.F. Hoese and Y. Yogo, 14 May 1980 ; AMS I.27367-007, 1(27), Amitori Bay , Iriomotejima, 16 February 1976 ; NSMT-P49186 , 2 (27–33), Ishigaki-jima , Yaeyama Group, Ryukyu Islands, 10 December 1995 . PHILIPPINES: AMS I.21907-003, 4(16–34), S of Anilao , Batangas Province, C. Ferraris and E. Murdy, 22 April 1980 ; AMS I.40155-059, 1(36), S coast Ambulong Island , MIN team, 1 June 2000 ; AMS I.40161-079, 3(26.5–31), Mindoro Island , 3 June 2000 ; USNM 298581 , 6 (38–47), Y’ami Island, Batanes, 26 April 1987 . AUSTRALIA: AMS I.28993-009, 1, W side near Wreck Point, North Keeling Island , Cocos-Keeling Islands ; AMS I.19641-022, 2(37.5–40), off Tantabiddi Creek , Western Australia, G . R. Allen , 27 June 1975 ; AMS I.33749- 122, 12(19–33), E side northern lagoon, Boot Reef, Coral Sea, FNQ team, 28 January 1993 ; NTM S.13618-020, 8(23–34), E side northern lagoon, Boot Reef, Coral Sea, FNQ team, 28 January 1993 ; AMS I.20774-107, 7(24.5–40), N tip of un-named reef, Cape Melville, Queensland, AMS-AIMS Survey, 9 February 1979 ; AMS I.20757-072, 10(21–36), W end of Raine Island , Queensland , AMS I.22635-005, 1(35.5), Escape Reef North, November 1981 ; AMS-AIMS Survey , 13 February 1979 ; AMS I.17445-049, 1(42.5), C transect, One Tree Island , F. Talbot and party, 19 September 1968 ; USNM 308212 , 15 (33–39), reef flat on SE side One Tree Island , Queensland , V.G. Springer and party, 27 November 1966 ; AMS IB.3916, holotype of Gnatholepis inconsequens , 1(32.5), Heron Island , Queensland , R. Slack-Smith , 1957 ; AMS IB.4004, 2(37–42.5), Heron Island , Queensland , R. Slack-Smith , 1957 ; AMS I.30310-034, 1(26), SW side North Solitary Island , New South Wales, 5 May 1977 ; AMS I.18659-001, 1(36), Seal Rocks , New South Wales, 10 May 1985 ; AMS I.19500-003, 1(31.5), Parsley Bay , Sydney Harbour, New South Wales , R. Kuiter , 2 February 1976 ; AMS I.27156-035, 7(33–53), lagoon, Elizabeth Reef , Tasman Sea, S. Reader, A. Gill, D. Ledbitter, 14 December 1987 ; AMS I.27142-030, 6(33–55), lagoon, Middleton Reef, Tasman Sea , AMS party, 7 December 1987 ; AMS I.27138-055, 11(21–44), mid-back lagoon, Middleton Reef , Tasman Sea, S. Reader, A. Gill, D. Ledbitter, M Cordell, 5 December 1987 . NEW GUINEA: NTM S.13661-047, 5(23.5–40), outer barrier reef S of Rasch Passage, Madang , H.K. Larson and M. Jebb, 5 October 1992 ; NTM S.13691-016, 1(30), S end Tab Island, near Christensen Research Institute , Madang, H.K. Larson and M. Jebb, 25 October 1992 ; NTM S.13685-044, 3(20–40), reef N of Tab Island, near Christensen Research Institute , Madang, H.K. Larson and M. Jebb, 21 October 1992 . MICRONESIA: USNM 224767 , 4 (27–30), N coast Ponape, Caroline Islands, 4 September 1980 . SOLOMON ISLANDS: NTM S.12714-008, 1(37), Munda Lagoon reef, S. Blaber, May 1989 . FIJI: USNM 243062 , 6 (25–33.5), Yanutha Islet, Ona Llau, Lau Group ( Eastern Archipelago ), 29 April 1982 ; BPBM 14591 , 2 (27.5–30.5), outside Mbengga barrier reef, Frigate Passage, Viti Levu, 11 March 1973 . TONGA: USNM 340186 , 1 (25), Ofolonga Island , Ha’apai Group, 12 November 1993 . NEW CALEDONIA: MNHN 1980-744 , 1 (36), coral reef, P. Laboute and Menou, January 1979 . VANUATU: AMS I.37905-034, 1(28), Siviri village, Efate Island , J. Williams and party, 4 May 1997 . KIRIBATI: USNM 116115 , 1 (32.5), Hull Island Channel, Phoenix Islands, L.P. Schultz, 1939 . MARSHALL ISLANDS: USNM 34429 , holotype of Gnatholepis scapulostigma , 1(36.5), Engebi Island , Enewatak, A.D. Welander, 11 August 1949 . AMS I.37692-002, 1(36.5), Eniwetok Atoll , R. Nolan , 28 May 1972 . HAWAII: BPBM 37847 , holotype of Gnatholepis cauerensis hawaiiensis , 1(35), N shore off Pupukea, Oahu , R. Holcom , August 1997 . BPBM 37861 , 3 (14–38.5), Kona coast off airport, Hawaii, J. Randall, 22 September 1997 ; BPBM 15131 , 13 (24–42), Baldwin Packer’s property, Maui, W. Gosline and E. Hunter, 5 August 1955 . SOCIETY ISLANDS: CAS 51602, 5 (26–36), W side Papetoai Bay , Moorea, 18 September 1956 ; CAS 51528, 1 (24.5), inside Teputo Pass, Papeari District , Tahiti, 4 July 1957 ; BPBM 8108 , 2 (24.5–35), Popote Bay , Papara, Tahiti, 13 March 1969 . MNHN 1980-94 , 1 (32.5), Gambier Islands, P. Fourmanoir ; AMS I.22176-003, 4(33–37), Ahahu Bay , Nuku Hiva, 3 September 1976 ; BPBM 11869 , 8 (21–53), N end Hanau Bay, Fatu Hiva , Marquesas, J. Randall, D. Cannoy , R. McNair , 21 April 1971 ; BPBM 11003 , 2 (29.5–42), W side Ua Huka , N of Mt Takatai, Marquesas, J. Randall, J. Haywood , R. McNair , 7 May 1971 ; BPBM 12621 , 3 (28–39), S end Akuoa Bay, Nuku Hiva , Marquesas, J. Randall, D. Bryant , R. McNair , 12 May 1971 ; BPBM 10398 , 1 (330, Hevane Bay, Hana , Tahuata, Marquesas, 16 October 1961 ; BPBM 12764 , Nuku Hiva, to Haurei Bay, Rapa , Austral Islands, J. Randall and D. Cannoy, 10 February 1971 ; BBPBM 17319 , 1 (35.5), entrance to Haurei Bay, Rapa , Austral Islands, J. Randall and D. Cannoy, 14 February 1971 ; BPBM 17267 , 1 (38), E side Akatamiro Bay, Rapa , Austral Islands, J. Randall and D. Cannoy, 8 February 1971 ; USNM 379839 , 2 (38.5–40), Anarua Bay , Rapa, Austral Islands, J . T. Williams and party, 7 November 2002 ; USNM 379757 , 4 (19.5–33.5), NW of Isle Tautoroa, Baie Anatkurinako, Rapa , Austral Islands, J . T. Williams and party, 13 November 2002 ; USNM 379741 , 5 (20.5–37.5), N coast of Point Kauira, Rapa, Austral Islands, J . T. Williams , 15 November 2002 ; USNM 379787 , 2 (23–31), S of Isle Tauna at mouth of Haurei Bay , Rapa, Austral Islands, J . T. Williams and S. Planes, 15 November 2002 ; USNM 379718 , 3 (35–39), N side channel, Haurei Bay , Rapa, Austral Islands, J . T. Williams and party, 19 November 2002 ; USNM 379630 , 3 (35–39), N end of Point Tematapea, Rapa, Austral Islands, J . T. Williams , 19 November 2002 . PITCAIRN ISLANDS: BPBM 16846 , 2 (38.5–41.5), off Bounty Bay , Pitcairn, J. Randall and party, 26 December 1970 .

Other material; no data taken. YEMEN: SAIAB 69164 , 1 (36), 12° 44’ N 14° 42’ E, Ras Imram, Gulf of Aden , south Yemen , P. and U. Zajonz, 24 March 1998 . SOUTH AFRICA: SAIAB 53491 , 1 , Tshani, Transkei ; SAIAB 74853 , 1 , Eelskin , Kwa-Zulu Natal ; SAIAB 46430 , 3 , Aliwal Shoal , Kwa-Zulu Natal ; SAIAB 69382 , 3 , Aliwal Shoal , Kwa-Zulu Natal . MOZAMBIQUE: SAIAB 74506 , 2 , Inhambane . ALDABRA: USNM 32547 , 2 , Aldabra Atoll . TANZANIA: BPBM 16392 , 1 , Chole Bay, Chole Island, Mafia Island . SEYCHELLES: USNM 327484 , 29 , St Joseph Atoll , Amirantes Islands . MAURITIUS: SAIAB 57882 , 9 , Flic en Flac ; SAIAB 52054 , 3 , Albion Fisheries Research Centre ; USNM 308208 , 21 , Agalega Islands . MALDIVES: BPBM 34390 , 4 , Furana Island, North Malé Island; BPBM 34574 , 2 , South Malé Island. PHILIPPINES: AMS I.21922-009, 4, Caban Island , Batangas Province ; AMS I.21908-002, 8, Sombrero Island , Batangas Province ; USNM 261671 , 8 , Negros Oriental . INDONESIA: BPBM 32249 , 1 , Tulamben , Bali ; AMS I.34501-018, 1, Waliti, Sao Wisata Resort, Flores ; NSMT-P.71338, 4, Terawangan Island, Lombok ; NSMT-P.71354, 18, Ambon Bay, Ambon ; NSMT-P.64522, 6, Kotania Bay, Seram ; BPBM 37362 , 1 , Kebola Bay, Alor ; BPBM 36644 , 1 , Nil Desperandum Reef, Banda Sea ; BPBM 37641 , 1 , Sarabua Bay, Siberut Island , Mentawi Islands . TAIWAN: SAIAB 31091 , 4 , Kenting National Park . JAPAN: AMS I.27366-002, 1, Amitori Bay, Iriomote-jima . JAPAN: BPBM 15021 , 2 , Ishigaki-jima , Ryukyu Islands . MICRONESIA: USNM 224765 , 12 , Ponape, Caroline Islands . PAPUA NEW GUINEA: USNM 327485 , 5 , Madang Harbour. AUSTRALIA: AMS I.28992-009, 1, Horsburgh Island , Cocos-Keeling Islands . NTM S.12883-015, 15, Cartier Reef, Timor Sea , Western Australia ; NTM S.11061-007, 3, One Tree Island . NEW CALEDONIA: MNHN 1980-158 , 3 ; MNHN 1980-124 , 1 , Ouvea , Loyalty Islands . VANUATU: AMS I.39010- 100, 1, Santa Cruz ; USNM 380364 , 2 . FIJI: USNM 243207 , 9 , Viwa Island . MARSHALL ISLANDS: AMS

I.37709-003, 1, Eniwetok; USNM 368817, 16, Bikini Atoll. TONGA: USNM 340172, 16; USNM 340191, 6; USNM 340185, 3. SOCIETY ISLANDS: ex-MNHN 1984-168, 3, Tiahura, Moorea.

Description. Based on 117 specimens, 24.5–56 mm SL. An asterisk indicates the counts of the holotype of Gobius cauerensis .

First dorsal VI *; second dorsal I,10–I,11* (mean I,11.1); anal I,10–12 (mean I,11.2, 11 in holotype), pectoral rays 12–18 (mean 16.3; 16 on right side, 17 on left in holotype), segmented caudal rays nearly always 17*; caudal ray pattern nearly always 9/8*; branched caudal rays 6/5 to 8/7 (usually 7/6, 7/ 7 in holotype); lateral scale count 24–30 (mean 26.7, 25 in holotype); TRB 8 ½–12 (mean 10.0, 9 in holotype); predorsal scales 7–12 (mean 8.8, 10 in holotype); circumpeduncular scales 11–13 (mean 12.2). Gill rakers on outer face of first arch 1–2 + 3–4 (in 25, usually 1+4) .

Body compressed, width at anus 10.4–15.5% (mean 13.1%) of SL. Body rather slender in appearance, body depth at anus 13.7–24.9% (mean 21.6%) of SL, body depth at first dorsal fin origin 18.3–24.7% (mean 22.2%) of SL. Head compressed, slightly broader ventrally, slightly deeper than wide, HL 24.1–30.7% (mean 27.4%) of SL; head depth at posterior preopercular margin 62.0–81.0% (mean 68.6%) of HL; head width at posterior preopercular margin 57.8–78.5% (mean 67.5%) of HL; head profile bluntly pointed to rounded; nape profile low, slightly convex. Mouth subterminal to nearly terminal, slightly oblique; jaws generally reaching to below anterior half of eye to just beyond front of eye; upper jaw length 27.1–40.5% (mean 34.6%) of HL. Upper lip smooth, narrower than lower, lower lip with papillose ridge close to teeth, with twist or fold posteriorly, forming triangular flap, lip narrowly interrupted at chin. Eye moderate to relatively small, dorsolateral, 20.1–31.3% (mean 26.8%) of HL; preorbital width 16.1–31.6% (mean 20.1%) of HL. Snout bluntly pointed to rounded, 21.1–39.0% (mean 32.2%) of HL; posterior naris round to almost triangular, close to anterior margin at middle of eye; anterior naris in short tube, higher on posterior margin of eye, about level with middle of eye or somewhat ventral to it. Interorbital narrow, 5.3–14.3% (mean 7.6%) of HL. Caudal peduncle compressed, length 11.4–23.4% (mean 16.2%) of SL; caudal peduncle depth 9.1–17.5% (mean 11.7%) of SL.

First dorsal fin rounded to roughly triangular, with no spines elongate; third to fourth dorsal spine longest; when adpressed, spine tips reaching to first to third element of second dorsal fin. Second dorsal spine length 15.1–21.7% (mean 17.3%) of SL; third dorsal spine length 13.1–22.2% (mean 17.6%) of SL. Second dorsal fin as tall as first dorsal fin, posteriormost rays usually longer than anterior, fin pointed to slightly rounded posteriorly. Anal fin lower than second dorsal fin, anteriormost rays shorter than posterior few rays; fin pointed to slightly rounded posteriorly. Second dorsal and anal fin rays, when adpressed, just reaching caudal fin rays. Pectoral fin oval to somewhat pointed, central rays longest, 18.6–28.6% (mean 25.7%) of SL; fin reaching back to above first few anal fin elements. Pelvic fins fused, frenum with distinctive finely fimbriate margin, fins round to somewhat oval, reaching to first anal fin elements, 22.9–31.5% (mean 26.9%) in SL. Caudal fin moderate, oval to rounded, 23.7–34.3% (mean 30.5%) of SL.

Gill opening restricted, extending anteriorly to lower edge of pectoral base or to just under opercle. Up to three slender gill rakers on outer face of first arch, close to angle of arch, remaining few rakers very short, pointed; pointed papillae present along inner face of first arch; outer rakers on second gill arch consisting of two series of papillae, one low and one (mostly anterior) of slightly pointed papillae; outer rakers on remaining arches low, stubby, broad-based. Inner face of upper limb of first gill arch, and to lesser extent, upper limbs of other arches, covered with low dense fleshy papillae, usually forming clumps or groups; dorsal portion of arch may have short fleshy protuberances ending in one or several papillae; inner face of second arch smooth, without papillae but with series of short fleshy rakers with rounded, finely papillose tips. About one quarter to one-third of first gill arch bound by membrane to inner face of opercle. Tongue short, tip bilobed to concave.

Teeth in upper jaw in two to three rows across front and one row at side of jaw, outermost row teeth largest, curved and pointed, largest teeth at front of jaw on either side of symphysis (smaller in females); innermost row teeth very small, sharp and evenly sized. Teeth in lower jaw in two to three rows, arranged similarly to upper jaw but outer row teeth may be smaller (in females); posteriormost one to three outer row teeth enlarged to somewhat recurved in males.

Predorsal scales cycloid, ctenoid body scales usually reaching forward to rear corner of opercle to just over opercle, occasionally ctenoid scales reaching forward to above rear preopercular margin; nape midline scales always cycloid ( Fig. 4C–D ). Opercle covered with cycloid scales, a few ctenoid scales may be present. Preopercular scales cycloid, occasionally extending anterior to vertical dark cheek-bar below eye. Breast with cycloid scales reaching up to below mid-opercle or to below rear half of opercle. Pectoral fin base covered with cycloid scales; occasionally with some ctenoid scales. Belly scales along midline usually cycloid; ctenoid scales may be present posteriorly.

Head pores as in G. anjerensis ( Fig. 1 ), as are the sensory papillae.

Coloration of fresh material. Good illustrations of living fish are shown in Senou et al. (2004: 242), Hayashi and Shiratori (2003: 97, as G. scapulostigma ), Kuiter and Tonozuka (2001: 673, as G. cauerensis and G. scapulostigma ), Myers (1991: pl. 124B, C; 1999: pl. 161E), while fresh-dead specimens are shown in Randall and Greenfield (2001: pl. I, G, H; pl.II, A–D). Anderson (2005: 97) shows the western Indian Ocean spotted form from the Maldives.

The range of colouring shown in these publications, and others, shows that there is considerable variation in live colouring in G. cauerensis . Live fishes photographed on dark sand are the most intensely coloured (e.g. Randall & Greenfield 2007: 306, fig. 2). In our experience, determining what is “typical” for the species is difficult but the upper fish illustrated in Senou et al. (2004: 242) comes close (and see Fig. 13 ).

Gnatholepis cauerensis usually has the body translucent white with five to seven rows of small variably on base of caudal fin; narrow vertical black line on top of each eye, lines may join each other across interorbital space, and narrow black to reddish brown vertical bar crossing cheek below eye; small dark mark of variable shape (often broad U- or W-shaped) above pectoral fin base, with small yellow spot in centre; side of head with small purple-brown to reddish marks and blotches that often form a cluster on either side of the dark vertical bar crossing the cheek from below the eye; dorsal and anal fins transparent with rows of indistinct dusky fine streaks or spots; anal fin translucent pearly whitish; pectoral fin transparent with white speckling on membranes basally; pelvic fin translucent pale white; caudal fin transparent with translucent white rays with rows of thin streaks, lines or fine spots along membranes or edges of rays ( Figs 13–16 ).

Coloration of preserved material. Based on typically coloured specimens from Ceram (variations discussed below). Head and body yellowish white to whitish with up to seven variably developed thin brownish lines running along length of body; usually two most conspicuous lines (lines number 5 to 6 if counting down from dorsum) running from behind pectoral fin base, this pair of lines overlying six square to rectangular brownish blotches (these blotches may be underlain by five to six vertically oval, faintly brownish bars similar to those in G. anjerensis ); next most conspicuous pair of lines (numbers 2 to 3) running from just above pectoral fin base and becoming indistinct on upper part of caudal peduncle, this pair of lines enclosing a series of up to 10 diffuse brownish square blotches, usually more conspicuous on anterior part of body. Dorsum crossed by about nine faint dusky square saddles (first saddle on nape before first dorsal fin), which may coalesce with the square blotches along upper part of body.

Predorsal, snout and side of head faintly blotched with pale brown; blotches along predorsal often paired. Opercle with (often indistinct) pale brown line from centre of preopercular margin obliquely back to upper half of opercle rear margin; line may curve up to rear corner of opercle. Narrow blackish, light brown to faint grey cheekbar from ventral edge of eye running vertically to slightly obliquely down to end on lower preopercular edge, but not extending onto branchiostegal membranes. Dense blackish to dark brown line from middle to rear half of iris running over top of eye (line may be slightly oblique), may meet its counterpart in interorbital space. Upper lip whitish, crossed by short brownish bar (starting from below anterior naris) as in G. anjerensis ; similar brownish bar or line at middle of lip. Cheek with diffuse brownish horizontal line crossing vertical cheek-bar; brownish line variable in shape and intensity, its pigment often surrounding one or two round pale spots. Above pectoral fin base, brownish to dark brown, roughly U-shaped flat-based blotch surrounding small very pale brown round spot; brown blotch often partly connected to brown line (may be partly broken-up or indistinct) running from behind eye along top of preopercle; blotch usually paler in small specimens. Pectoral fin base with horizontal light brown line crossing just above middle of fin base, line usually extending onto lower part of fin.

First dorsal fin transparent, with about three thin wavy light brown horizontal lines beginning at first spine; lowermost one or two lines darkest, especially anteriorly; distal part of fin may be plain pale brownish. Second dorsal fin with similar few thin light brown horizontal lines which, after the first few fin rays, transform into plain brown pigment or series of vertical dark streaks on membrane between fin rays; in some specimens fin almost unpigmented. Anal fin plain dusky to brownish, may be darker distally. Caudal fin transparent to translucent brownish, sometimes with pale brown streaks or rows of fine brown spots along fin membranes, especially near fin base. Pectoral fins transparent to translucent dusky. Pelvic fins and frenum translucent plain pale brownish, may be darker between fourth and fifth rays.

Variation. A number of specimens from a range of localities (Kwa-Zulu Natal to the Philippines to the Marquesas) are more heavily marked (though often from white-sand habitats), with all markings darker ( Fig. 15 ). The seven lines along the body are intensified into a series of dark brown partly connected spots, the six rectangular blotches along the mid-side of the body are more prominent purplish brown, the thin lines along both dorsal fins are dark brown to blackish anteriorly and are broken into series of spots; those along the second dorsal fin tending to form short longitudinal streaks with none of the vertical dark lines between rays. The caudal fin is crossed by many rows of small dark spots, which are slightly larger and darker toward the fin base.

In particular, photographs of specimens from western Indian Ocean locations such as Kwa-Zulu Natal coast, South Africa, Mauritius and Maldives all show a similar spotted pattern ( Fig. 16 ). These fish are almost identical in colour pattern to G. thompsoni .

Specimens from Rapa (which show lines, not rows of spots, along the body) show a similar pattern on the caudal fin: thin light brown lines following the fin rays, darker toward the centre and base of the fin. This pattern is also found in specimens from Hawaii (which Greenfield & Randall (2001) placed in subspecies G. c. hawaiiensis ). Among the largest specimens examined, from Taiwan and Middleton Reef, specimens have the six or seven horizontal lines along the body considerably darker, with the two to three lines closest to the mid-side of the body partly extending on to the caudal fin. One Middleton Reef specimen is heavily marked with dark lines along the body. Many Hawaiian specimens are similarly strongly marked (some labelled as being from black sand habitats), having six or seven dark brown lines along the body. This pattern is also seen in photographs of living fish from localities such as Izu Peninsula ( Japan) and Normanby Island (New Guinea) ( Fig. 17 ).

Distribution. A wide-spread Indo-Pacific species, known from South Africa to Pitcairn Island, in the Pacific north to Miyake-jima, Japan and south to Sydney Harbour, Australia, and in the Indian Ocean north to Djibouti

Comparisons. This species has frequently been confused with G. anjerensis but can be distinguished from it by having cycloid predorsal scales (versus ctenoid predorsal scales in G. anjerensis ); its smaller size and generally slender appearance (up to 56 mm SL versus 84 mm SL and generally stocky appearance of G. anjerensis ); having a generally rounded to roughly triangular first dorsal fin with third or fourth dorsal spine longest (versus roughly square in shape, with fifth dorsal spine nearly as long as third to fourth spines in G. anjerensis ); body pale with five to seven rows of small orange, brown, red-brown to blackish spots and/or thin lines and about six indistinct diffuse orange-brown to purple-brown blotches along mid-side (versus pale body covered with irregular rows of small blackish to reddish spots and five to six diffuse dusky blotches along the lower mid-side of the body, and blue spots on side of head and anterior part of body in G. anjerensis ); and small dark mark, often W-shaped, above pectoral fin base, with small yellow spot in centre (versus small round orange to gold spot, often with short dark line underneath, in G. anjerensis ).

Remarks. The holotype of Gobius cauerensis Bleeker, 1853 , is one of two specimens tied together in RMNH 4523 (31.2–32.6 mm SL; 38.9–39.9 mm TL), with its size given in the original description as 39 mm TL; the second smaller specimen is thus the holotype ( Fig. 18 ). Randall and Greenfield (2001) give the holotype number as RMNH 6523.

Gnatholepis scapulostigma Herre, 1953 , was described from the type (and only specimen), a male 36.5 mm long, but Herre did not state where the type was deposited. Randall and Greenfield (2001) found it in the USNM main collection (USNM 344429), not labelled as a type but agreeing otherwise with data in Herre’s description. They state the fish has 10 anal fin rays and 17 pectoral fin rays; we obtained counts of 11 anal rays and 16 pectoral.

Gnatholepis inconsequens Whitley, 1958 , was described from Heron Island on the southern Great Barrier Reef. Randall and Greenfield (2001) placed this as a synonym of G. cauerensis based on pectoral fin ray count. Other specimens from the area, including AMS material collected at the same time as the type, are G. anjerensis . Although the specimen is stained green (from “copper-stained formalin” ( Whitley 1958)), the typical G. cauerensis dark shoulder blotch can be discerned and the pectoral fin lacks the speckling of melanophores as found in G. anjerensis (all predorsal scales are missing).

Wass (1984) briefly described a pale Gnatholepis from Samoa (AMS I.22003-001); his description agrees with G. cauerensis . Many records of G. anjerensis in the literature before the 1990s refer to G. cauerensis and vice versa, due to confusion over the use of these two names (see Myers 1991, 1999).

Gnatholepis cauerensis australis was described as a subspecies by Randall and Greenfield (2001) from Haurei Bay, Rapa, French Polynesia (holotype BPBM). This material was first tentatively identified as G. anjerensis by Randall et al. (1990b). Randall (2009: 180–181) brought this to full species status, based on its pectoral fin ray counts of 17–19 (modally 19), compared to G. cauerensis ’ pectoral ray counts of 16–19 (modally 17), based on 10 BPBM specimens (Randall included counts from both sides in his Table 1 of 2009). We found pectoral ray counts of 14–19 (modally 18), based on 19 Rapa specimens from BPBM and USNM. A difference in adult size between G. australis (sensu Randall 2009) and G. cauerensis is remarked upon by Randall (2009), who cites 40 mm SL as the largest G. cauerensis out of 80 specimens that he had examined, with only two being over 38 mm SL, while the 31 specimens of G. australis he looked at included eight over 38 mm SL, with the largest being 49 mm SL. Of the 117 G. cauerensis we examined, the largest specimen was 56 mm SL (from Marquesas), with other specimens over 50 mm SL from Taiwan, Middleton Reef and Elizabeth Reef. The modal SL for all G. cauerensis was 39 mm, while mean SL was 37.8 mm. Of our 19 specimens from Rapa and Pitcairn, the maximum size examined was 41.5 mm SL, a mode of 35.5 mm and a mean of 35.7 mm SL. We leave G. australis as a synonym of G. cauerensis .

Randall and Greenfield (2001) described the subspecies Gnatholepis cauerensis hawaiiensis , from off Pupukea, Oahu, Hawaiian Islands (holotype BPBM 37847). They separated this subspecies from G. cauerensis cauerensis by its having a shorter caudal peduncle (in head length), in the caudal fin having a dark line along the membrane between rays instead of dark spots and in having small blue spots on the lower half of the body. Later Randall (2009) elevated the Hawaiian form to full species, G. hawaiiensis , on the basis of caudal peduncle length: 1.7–1.9 (in head length) in G. cauerensis and 1.5–1.7 in G. hawaiiensis . We were unable to determine a consistent difference in caudal peduncle length between any Gnatholepis species (mean length of 15.7–17.0% in SL). The lines, streaks and rows of dark spots on the caudal fin in G. cauerensis vary greatly, with specimens from localities of the head and body vary also (more heavily pigmented specimens more likely to show these pale spots)—and are usually only discernible in photographs of living or recently dead fish. Therefore we do not agree with Randall (2009: 181) that the Hawaiian form is a separate species.

One specimen from Ras Imran in the Gulf of Aden, Yemen (SAIAB 69164) resembles G. caudimaculata but lacks the vertical dark blotch on the caudal base (has the faint short horizontal mark typical of G. cauerensis ) and has a straight (not curved) black line atop the eyeball. This specimen is the “farthest north” that we have examined for G. cauerensis .

Randall (in litt. to HKL) considered that G. cauerensis specimens from Marquesas constituted an undescribed species, due to differences in colour and pectoral fin ray count. In Randall (1985), Marquesas specimens are identified as G. anjerensis ; in Randall and Earle (2000) they are identified as G. cauerensis . One of the fish (one of three in BPBM 12621) is shown in Plate IIA of Randall and Greenfield (2001). Five Marquesas specimens (in BPBM 12621, 11869, 11003) had counts of 17 pectoral fin rays and five had 18. A SAIAB specimen photographed from Mauritius (not examined) and a wild fish from Bali, Indonesia, photographed by Rudie Kuiter (not collected) have similar heavy spotting to the Marquesas fish, with the adjoining lines hardly visible and only five lateral blotches present, not six. The variation in these fishes gives one much to think about.

It is of concern that some specimens identified by Randall and Greenfield in 2001 as G. anjerensis , were subsequently identified by us as G. cauerensis . These include fish from Heron Island and Middleton Reef, Queensland, and may be some of the “exceptional” specimens from the southern Great Barrier Reef that they mention as having distinct longitudinal lines on the body ( Randall & Greenfield 2001: 5). Many specimens and

In Thacker (2004a: 576), Figure 2 shows a strict consensus tree with three unlabelled outliers grouped together at the base of her G. scapulostigma (= G. cauerensis ) clade. These were two specimens from Moorea and one from Aitutaki, Cook Islands, and there was no morphological information to indicate that they were different (Thacker, in litt. 27/1/06). Other specimens from the same two localities grouped with her G. knighti clade (but separately from material from Hawaii).

Figures

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

FIGURE 2. Canonical analysis of principal co-ordinates plot for the seven Gnatholepis species with vectors overlaid. CAP axes 1 and 2 explain 62% of the variation from 13 canonical axes.

FIGURE 4. Diagram showing variation in ctenoid and cycloid scale arrangement on the predorsal (nape) region in specimens of A-B, Gnatholepis anjerensis from Mauritius and Ambon respectively, C-D, G. cauerensis, both from Aliwal Shoal, South

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

FIGURE 13. Gnatholepis cauerensis, Scott Reef, Western Australia. Photo by Gerry Allen.

FIGURE 14. Gnatholepis cauerensis, Flores, Indonesia. Photo by Rudie Kuiter.

FIGURE 15. Gnatholepis cauerensis over dark sand, Tulamben, Bali, Indonesia. Photo by Gerry Allen.

FIGURE 16. Gnatholepis cauerensis, from Sodwana Bay, Kwa-Zulu Natal, South Africa, showing great similarity to G. thompsoni. Photo by Phil Heemstra.

FIGURE 17. Gnatholepis cauerensis over dark sand, Normanby Island, Papua New Guinea. Photo by Gerry Allen.

FIGURE 18. Gnatholepis cauerensis, smaller specimen is holotype of Gobius cauerensis, RMNH 4523. Photograph by Doug Hoese.