JapaneseV Journal of Ichthyology 魚 類 学 雑 誌 ol.23,No.41977 23巻4号1977年

Signigobius biocellatus,a New and of Sand-dwelling Gobiid from the Western Tropical Pacific

Douglass F.Hoese and Gerald R.Allen Received August 18,1976) (

Abstract Signigobius biocellatus is described as a new genus and species of coral reef gobiid fish from Palau,the Philippines,Solomon Islands,New Guinea,and the Great Barrier Reef,The genus is compared with other sand-dwelling coral reef genera in morphological and ecological aspects.The genus is most similar in these aspects to the genus Valenciennea.

generally more consistent in gobiids since the Introduction scales below the first dorsal fin are often Until the last 10 years little was known of crowded and irregularly placed. the and ecology of Indo-Pacific The osteology was studied from trypsin coral reef gobiid .Even today little cleared and stained material.Vertebral counts published information is available.It is were taken from cleared and stained material estimated that approximately 400 to 600 of and radiographs. the 2000 gobiid fishes in the world live on Indo-Pacific coral reefs. Signigobius,gen.nov. Specimens of Signigobius were first discov- Type species:Signigobius biocellatus,sp. ered in Palau by the junior author in 1971. nov. Subsequently they have been collected in For diagnostic characters of the genus see several localities in the western Pacific Ocean. Table 2. We examined various museum collections and First dorsal fin with six spines.Pelvic fins found that a specimen was collected in 1909 connected to form a cup shaped disc.Head by the"Albatross"and three were collected compressed.Tongue tip broadly rounded. in 1944.Of the 78 specimens known,all but Gill opening narrow,extending from upper four have been collected since 1968. margin of pectoral base to a point just below Field observations indicated that the genus lower margin of pectoral base.First gill arch was ecologically similar to Valenciennea,and not connected by membrane to inner face of detailed examination indicated that the two operculum.Gill rakers on outer part of first genera are very closely related.We have gill arch developed only on posterior part of observed Signigobius and Valenciennea digging lower limb of arch.Upper limb of first arch their own burrows and Amblygobius also con- with prominent fleshy lobes at uppermost part structs its own burrow(Klausewitz,1960;H.K. of limb.Minute close-set comb-like gill rakers Larson,pers.comm.), on inner face of fourth gill arch.Anterior nostril a short slender tube positioned half Methods way between anterior margin of eye and Counts and measurements follow Hubbs and anterior margin of snout;posterior nostril,a Lagler(1958).The transverse scale count was pore positioned about midway between anterior made in two ways; from the anal origin margin of eye and anterior nostril.No flaps upward and backward to the base of the on shoulder girdle.Body covered largely with second dorsal fin(TRB)and from the anal moderate sized ctenoid scales;cycloid on origin upward and forward to the base of the ventral surface of belly and anteriorly just first dorsal fin(TRF).The TRB count is behind pectoral base and below first dorsal

―199― 魚類学雑誌 Japan.J.Ichthvol.23(4).1977 fin.Midline of nape and head naked.Seven- posterior and dorsal part of orbit.Supraoc- teen segmented caudal rays. cipital diamond shaped,with prominent A single row of conical curved wideset teeth anterior flange covering part of frontal;lateral covering most of premaxilla;a large gap wings prominent and wedge shaped.Sphenotic anteriorly between left and right sides of jaw with a low rounded dorsal flange widely w ith no teeth.In specimens larger than 35mm separate from supraoccipital.Glossohyal SL.a single small tooth on each side of jaw triangular,broader than long.Scapula absent. anteriorly behind anterior row.Lower jaw First dorsal fin with six pterygiophores with two rows of teeth;an outer row com- articulating after third neural arch and spaced posed of curved conical teeth about equal in with respect to interneural spaces 2-2-1-1. size to upper jaw teeth,covering anterior the number indicates the number of ptery- part of'dentary;an inner row of slightly giophores between successive neural spines. larger teeth anteriorly with one or two An interneural gap without a pterygiophore enlarged teeth at bend of dentary and two or between two dorsal fins.Anterior zygapophyses three smaller teeth behind bend of dentary. weakly developed on second to fifth vertebrae. Head pores(Fig.5a):a pore between Dorsal ribs associated with vertebrae one to anterior and posterior nostrils;a median twelve.last four free from vertebrae.Ventral anterior interorbital pore between anterior ribs associated with vertebrae three to eleven. margin of eyes;a median posterior interorbital Caudal skeleton with a single epural.Verte- brae10+16=26. pore between posterior margin of eyes:a Etymology.Latin,signus=mark and gobius postorbital pore behind each eye;an infraor- bital pore below each postorbital:a lateral =a genus of fish,alluding to distinctive canal pore over preoperculum;a terminal coloration. lateral canal pore above posterior margin of Signigobius biocellatus,sp.nov. preoperculum;a short tube with pores at each end above operculum;and three preopercular (Figs.1.2,3.4A,5A) pores. Description.Based on specimens13to56mm Osteology.Branchiostegal rays 5.No SL.morphometrics based on specimens20to postcleithrum.No mesopterygoid.Metaptery- 56mm SL.Counts of holotype indicated by goid slender,without process extending over an asterisk. quadrate.Sphenotic short,flange supporting First dorsal VI(in39specimens)*.Second hyomandibular fused with flange forming dorsal1.10(in1);I.11(in38)*.Anal 1. posterior part of orbit.Preoperculum without 11(in38)*:1,10(in1).Pectoral20(in7): a process extending to posterior flange of 21(in19)*;22(in2).Segmented caudal rays hyomandibular.No hyomandibular process 15(in1):16(in1);17(in28)*.Branched from posterior flange to preoperculum.Frontal caudal rays0(in1);11(in3):12(in3):3 not prolonged,frontal ridge large,forming (in18)*.Procurrent caudal rays 8/8(in1):

Fig.1.Holotvpe of Signigobius biocellalus,AMS1 18767-001.Photo by G.Millen.

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Fig.2.Paratype of Signigobius biocellatus,UNSM 215044 .

8/7(in2);7/7(in1);7/6(in2);6/6(in2): cular margin.Snout longer than eye length, 6,5(in1).Gillrakers on outer face of first varying from12.8to14.8%of SL in speci- arch4(in1);5(in4);6(in1).Gillrakers mens less than28mm SL to10 .5to12.6% on outer face of second arch 12(in2);13 of SL in larger specimens;snout convex and (in1);14(in1).Longitudinal scale count gently sloping in lateral view.Eye small. 48(in3);49(in2);50(in3);51(in2);52 8.7to10.5%of SL in juveniles smaller than (in6);53(in3);54(in2)*;55(in2).Trans- 28mm and6.2to8.2%of SL in larger speci- verse scale count forwards(TRF)18(in2): mens.Mouth moderate,slightly oblique, 19(in5);20(in6);21(in5)*;22(in2). forming an angle of about15to20'with Transverse scale count backwards(TRB)16 body axis;jaws end under a point below (in1);17(in10)*;18(in7);20(in2);21 anterior margin of eye in young,less than (in1).Branchiostegals5(in5).Teeth on 20mm,to under middle of pupil in adults; left side of upper jaw13(in2);14(in2)*; upper jaw11.7to14.5%of SL.Interorbital 15(in4);16(in2);17(in2).Vertebrae narrow,about equal to pupil diameter. 10+16(in10). Gillrakers on outer face of first arch elongate. Measurements of the holotype and five developed only on posterior half of lower paratypes are shown in Table1. part of arch.Inner rakers of first arch well Head slightly compressed,width at preoper- developed.Gillrakers developed only along cular margin0.84to0.92of depth at preoper- middle of second to fourth arches.No fila-

Table1.Measurements of holotype and paratypes of Signigobius biocellatus,in millimetres .

―201― 魚類学雑誌 Japan.J.lchthyol.23(4),1977 mentous dorsal spines.Body completely regular longitudinal stripes:two ocellated spots, scaled:nape with scales at sides,in adults each about equal to eye length;the first a black only,extending forward to just above posterior spot on first dorsal between fifth and sixth margin of preoperculum.Gut elongate and dorsal spines,surrounded by a yellow ring,in coiled.Urogenital papilla of male pointed, turn surrounded by a dusky greyish ring:second recessed in groove in body cavity;in females spot similarly coloured near end of second a rounded lobe with two large lateral fleshy dorsal fin between ninth and twelfth rays. flaps. Caudal transparent.Pelvic jet black with Colouration of live and fresh material from small scattered irridescent blue spots,and a Palau and Lizard islands.Head and body narrow white distal margin.Anterior fifth of grey to white.A vertical pinkish bar with anal usually white;remaining part of fin jet brown edges,width about equal to pupil black with three or four longitudinal or oblique length.extending from ventral margin of eye rows of small irridescent blue spots:a narrow to below posterior end of jaw.Sides of head white distal margin,Pectoral fins clear. with brown lines forming reticulated pattern Colouration in alcohol.Same as live around white spots.An irregular brown colouration,except all traces of pink,yellow blotch with scattered white spots on operculum. and blue absent.Rings of two dorsal spots Top of head,nape and upper half of body clear.Pelvic and anal black,sometimes with with irregularly shaped small brown blotches traces of darker small spots. or small round brown spots.Three brownish Insufficient material is available to determine to black diamond shaped blotches on mid side any geographical variation.The branching with narrower vertical bars of same colour of the caudal rays increases with growth. extending ventrally from blotches:first blotch Specimens smaller than 15mm have few,if on side of belly;second near anterior end of any.branched caudal rays. anal fin;third just behind or over posterior Ecology.This species lives over sand. end of anal fin.Middle of pectoral base with generally only one or two metres from coral an irregular brown stripe:about equal to pupil or rubble(Fig.31.The juveniles occur singly. length,Dorsal fins whitish with irregular but adults occur as male and female pairs. pinkish brown mottling forming two or three ir- Individuals feed by taking large mouthfuls

Fig.3.A male and female pair of Signigobius biocellatus from Lizard Island. Photo by D.F.Hoese.

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of sand,sifting it through the gill openings. Is.,30m,9 March 1972,G.Allen;AMS I Stomach analyses of three specimens indicates 18480-001,2(25•`28),Koror Is.,1m,16Dec. that the species feeds primarily on interstitial 1971,G.Allen;AMS I 18738-001,4(21•`32), copepods,but also takes in large numbers of Auluptagel Is.,2m,8Mar.1972,G.Allen; nematodes,foraminifera,ostracods,unidenti- WAM P 25539-001,1(24),taken with AMS fiable detritus,and small amounts of sand. I 18480;USNM 216210,1(15),taken with. When approached by predators Synodus spp. ANSP 134365.New Guinea:USNM 215043, juveniles were noticed to erect both dorsal. 1(32),Madang Harbour,2 to 8m,30 May fins revealing the eye spots and to hop in a 1970,B.B.Collette and party;USNM 215044, forward direction,keeping the head down. 1(36),Madang Harbour,23May 1970,B.B. Adults were observed feeding on the bottom, Collette and party.Solomon Islands:BPBM digging burrows with their mouths,or hover- 17990,1(33),Guadalcanal,10m,21 July ing above the substratum in pairs.When 1973,J.E.Randall;USNM 215045,2(34•`38), hovering the individuals move rapidly forward, Munda Lagoon,New Georgia Is.,16 July backward,upward,or downward.The above 1944;USNM 215046,1(29)Munda Lagoon, observations are based on about 6 hours of New Georgia Is.,16 July 1944.New Hebrides: underwater observation by the senior author AMS I 18434-002,2(25•`30),Efate,Jan.1974, at Lizard Island and the junior author at P.Fourmanoir,MNHN 1975-1,1(30),taken Palau.More details of their behaviour are with AMS I18434.Great Barrier Reef;Yonge discussed by Huson(1977). Reef:AMS 118740-001,1(13),backreef,9 Etymology.Latin,bi=two and ocellatus= to 12m,8 Nov.1975,D.Hoese,H.Larson, small eye spots,referring to the two prom- N.Coleman,R.Cummins,and R.Kuronuma. inent ocellated spots on the dorsal fins. Great Barrier Reef;Lizard Island:AMS I Material examined.Type material has 17682-003,1(37),June1973,B.Goldman; been deposited in the following institutions: AMS I 17686-013,1(45),North Point,9m, Academy of Natural Sciences,Philadelphia, 26 June 1973,D.Hoese;AMS I18754-001, ANSP;Australian Museum,Sydney,AMS; 1(55),lagoon,3 to 8m,7 Feb.1975,D. British Museum(Natural History),London, Hoese;AMS I18755-001,4(15•`56),AMS I BM(NH);Bernice P.Bishop Museum,Hono- 18739•`001,3(13•`24),lagoon,3 to 8m,21 lulu,BPBM;California Academy of Science, Nov.1975,J.Paxton and party;BM(NH) San Francisco,CAS;Museum National 1976.4.9.1,1(43),north end of island,10m, d'Histoire Naturelle,Paris,MNHN;National 18 May 1975,R.Lubbock;CAS 35953,5(17- Science Museum,Tokyo,NSMT;Queensland 23),lagoon,1 to 15m,17 Nov.1975,J.Paxton Museum,Brisbane,QM;United States Natio- and party;LACM 35670-1,1(42),taken with nal Natural History Museum,Washington, AMS I 18754-001;NSMT-P.18251,1(22), USNM;Western Australian Museum,Perth, North Point,8 to 15m,29 Jan.1975,D. WAM. Hoese and H.Larson;QM I13538,1(45), In the material examined list,for each taken with AMS I 18755-001;WAM P 24765, collection,the number of specimens is given 1(48),North Point,5m,4 May 1974,G. followed by the size range in standard length Allen;USNM216211,1(24),taken with AMS enclosed in parentheses. I18739-001.Great Barrier Reef;Linnet Reef: Holotype.AMS I 18767-001,a 32.2mm AMS 118767-002,1(14),taken with holotype. male;Linnet Reef,Great Barrier Reef,col- Great Barrier Reef;Northern Escape Reef: lected 22 November 1975 in6to15m,on USNM 215035,1(14),26 to 29m,23 Jan. sand,coral and rubble bottom by D.F.Hoese, 1969,J.Tyler and party;ANSP 134804,2

H.K.Larson,B.C.Russell,and N.Coleman. (27•`28),24 to 27m,24Jan.1969,J.Tyler Paratypes.Philippines:USNM99290,1 and party.Great Barrier Reef;Big Hope Is.; (41),Tipu,Boero Is.,Albatross Sta.2130,11 ANSP 134803,2(26•`30),8 to 11m,19 Jan. Dec.1909.Palau Island:ANSP 134365,3 1969,J.Tyler and C.L.Smith;USNM 215039, (15•`26),Malakal Passage,5 m,23 Jan.1973, 5(29•`35),8 to 11m,19 Jan.1969,J.Tyler G.Allen;AMSI18479-001,1(39),off Ngargol and G.Betties.Great Barrier Reef;Endeavour

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―204― Hoese and Allen:A New Genus and Species of Coral Reef Goby

Reef:ANSP134801,1(22),17to21m,15 Ctenogobiops differ further from the other Jan.1969,J.Tyler and C.L.Smith;ANSP three genera in feeding more selectively by 134800,7(14-28),11to15m,J.Tyler and taking small mouthfuls of sand and picking in- C.L.Smith;ANSP134802,1(13),14to15m, dividual prey organisms from sand.Signigobius, J.Tyler and C.L.Smith;USNM21042,13 Valenciennea,and Amblygobius all feed by (16-32),14to18m,J.Tyler and C.L.Smith. taking large mouthfuls of sand,sifting out minute organisms and species of all three Relationships of Signigobius genera dig their own burrows with their Superficially Signigobius resembles the mouths.All three have an elongate and. nominal Batman insignitus Whitley(1956), coiled gut,while Cryptocentrus,Vanderhorstia which has an ocellated spot on the first dorsal and Ctenogobiops have a short S-shaped gut. fin.Batman differs in having cycloid scales, From Table2,it is apparent that Cryptocentrus transverse head papillae rows,a broader gill differs considerably from these three genera opening,and several rows of teeth in upper in the structures associated with feeding.The jaw.All of these features are characteristic teeth are better developed for grasping,and of Cryptocentrus and we regard Batman as a the pharyngeal teeth and gill rakers are typical synonym of Cryptocentrus.The general head for predatory gobiids in Cryptocentrus. shape and single row of teeth in the upper Cryptocentrus also differs from Amblygobius, jaw of Signigobiusare similar to features found Signigobius,and Valenciennea in having a in Oxyurichthys.However,Oxyurichthys has broader gill opening(Table1)and in the paired anterior interorbital pores and is prob- arrangement of the head sensory papillae ably not closely related to Signigobius. (Fig.5).Amblygobius differs from Valencinnea Signigobius is most similar to the genera and Signigobius in the arrangement of the Valenciennea and Amblygobius(Table2). head papillae and other minor features(Table Cryptocentrus and the distantly related genera 1). Vanderhorstia and Ctenogobiops differ from Stomach contents of Valenciennea longipin- Signigobius,Valenciennea,and Amblygobius in nis,V.puellaris,and V.sexguttatus indicate occupying burrows constructed by alphaeid that the species feed largely on intersti- shrimps.Cryptocentrus,Vanderhorstia,and tial fauna,such as copepods,foraminifera,

Fig.4.Outer face of first gill arch in four gobiid genera. A.Signigobius.B.Valenciennea.C.Amblygobius.D.Cryptocentrus .

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Fig.5.Arrangement of sensory papillae in four burrow inhabiting coral reef gobiid genera. A.Signigobius.B.Valenciennea.C.Amblygobius.D.Cryptocentrus.

nematodes,amphipods,and ostracods;basi- Lachner for allowing us to use the fine drawing cally the same groups of organisms eaten by J.R.Schroeder(Fig.2). by Signigobius.,how- ever,apparently feeds largely on algae(H.K. Literature cited Larson,pers.comm.).Amblygobius differs from Signigobius and Valenciennea in the Harada, E. 1969. On the interspecific associa- tion of a snapping shrimp and gobiid fishes. structure of the first gill arch(Fig.4),and Publ. Seto Mar. Biol. Lab., 16 (5): 315•`334,

some species of Amblygobiushave more than figs. 1•`10.

one row of teeth in the upper jaw.Valencien- Hubbs, C. L. and K. F. Lagler. 1958. Fishes of nea and Signigobius differ only slightly in the the Great Lakes region. Cranbrook Institute development of the fleshy pads at the upper of Science, Bloomfield Hills, Michigan. 213

end of the first gill arch. pp., figs. 1•`251. Signigobius is most similar to Valenciennea, Hudson, R. C. L. 1977. Preliminary observa- and differs from that genus in having lower tions on the behaviour of the gobiid fish scale counts,a pelvic disc,and the nasal pore Signigobius biocellatus Hoese and Allen with adjacent to the posterior nostril. particular reference to its burrowing behaviour. Z. Tierpsychol., 43: 214•`220. Klausewitz, W. 1960. Fische aus dem Roten Acknowledgments Meer. IV. Einige systematisch und okologisch We would like to thank Ms.H.K.Larson bemerkenswerte Meergrundeln (Pisces, Gobi-

for drawing figures4and5and Dr.E.Lachner idae). Senck. biol., 41 (3/4): 149•`162, figs. 1•` for supplying material of this species.Dr.J. 10. Paxton kindly reviewed the manuscript.Dr. Whitley, G. P. 1956. New fishes from Australia R.Hudson made his manuscript available to and New Zealand. Proc. Roy. Zool. Soc. N. S. W. us.We would also like to thank Dr.E. 1954•`55: 34•`38, figs. 1•`2.

―206― Hoese and Allen:A New Genus and Species of Coral Reef Goby

(Hoese:The Australian Museum,Sydney,Aust- ア お よ び オ ー ス トラ リ ア の グ レ ー トバ リ ア ー リ ー フ ralia;Allen:The Western Australian Museum, で 採 集 さ れ た サ ン ゴ 礁 に 生 息 す る ハ ゼ 科 魚 類 の 新 属, Perth,Australia) 新 種 を 記 載 し た.本 属 を 形 態 お よ び 生 態 の 面 か らサ ン ゴ 礁 の 砂 地 に 生 息 す る 他 の 属 と 比 較 し た.本 属 は

太 平 洋 西 部 の 熱 帯 海 域 で 採 集 さ れ た サ ン ゴ 礁 の 砂 地 に こ れ ら の 点 で ク ロ イ トハ ゼ 属Valencienneaに 類 似 生 息 性 の ハ ゼ 科 の 新 属,新 種Signigobius biocellatus す る.

Douglass F.Hoese and Gerald R.Allen

パ ラ オ,フ ィ リ ピ ン,ソ ロ モ ン 諸 島,ニ ュ ー ギ ニ

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