TWONEW SPECIES OF THEGENUS GONEPLAX (DECAPODA, BRACHYURA,GONEPLACIDAE) FROM EAST ASIA BY HIRONORI KOMATSU andMASA TSUNE TAKEDA Departmentof Zoology, National Science Museum, 3-23-1 Hyakunincho, Shinjuku-ku, Tokyo169-0073, Japan ABSTRACT Twonew species of goneplacid crab, Goneplaxmarivenae and G. megalops,aredescribed from thePhilippines and Japan, respectively. Both new species are closely similar to G. sigsbei (A. Milne- Edwards,1880) from the western Atlantic Ocean in the form of the carapace, eyestalk, fourth ambulatoryleg, and male pleopods, but can be distinguished from G. sigsbei bythe form of the orbit.Both new species are also similar to G.maldivensis Rathbun,1902, but are distinguished from G.maldivensis bythe form of themale abdomen. Goneplaxmarivenae ismost closely similar to G. megalops,butcan be distinguishedfrom G. megalops bytheform of theextraorbital tooth and themale rstpleopod. RÉSUMÉ Deuxespè ces nouvelles de crabes Goneplacidae, Goneplaxmarivenae et G. megalops, sont décrites respectivement, des Philippines et du Japon. Les deux espè ces nouvelles sont trè s prochesde G. sigsbei (A.Milne-Edwards, 1880) de l’océ an Atlantique occidental par la formede lacarapace, les pédoncules oculaires, la quatrième patte ambulatoire, et les plé opodes mâ les, mais s’ en distinguent parla forme de l’ orbite. Les deux nouvelles espè ces ressemblent é galementà G.maldivensis Rathbun,1902, mais s’ en distinguent par la forme de l’ abdomen mâ le. Goneplaxmarivenae est leplus proche de G. megalops,maisen diffè re par la forme des dents extraorbitales et le premier pléopode mâ le. INTRODUCTION The genus Goneplax Leach,1814 currently consists oftwospecies fromthe At- lantic Ocean,viz., G.rhomboides (Linnaeus,1758) (the typespecies) and G. sigs- bei (A.Milne-Edwards, 1880), and vespecies fromthe Indo-Pacic (Serène & Umali, 1972),viz., G.sinuatifrons Miers, 1886, G.maldivensis Rathbun,1902, G.renoculis Rathbun,1914, G. wol Serène, 1964, and G. serenei Zarenkov,1972. Rathbun(1918) synonymized Frevillea A.Milne-Edwards,1880 with Goneplax, © KoninklijkeBrill NV ,Leiden,2004 Crustaceana 76(10):1243-1256 Alsoavailable online: www.brill.nl 1244 HIRONORI KOMATSU& MASATSUNET AKEDA butGuinot (1969) clari ed the identity of Frevillea and Goneplax,respectively. Serène & Soh(1976) established anewgenus, Singhaplax,to accommodatetwo species of Goneplax, G.ockelmanni Serène, 1971 (the typespecies) and G. nippo- nensis Yokoya,1933. InFebruary 2003, we hadan opportunity to take aeld trip to Balicasag Island, Bohol,Philippines, as apart ofaresearch project ofthe National Science Museum, Tokyo,entitled “Natural History ofthe West Pacic Archipelago”. Onthis, arrangedby Ms. MariveneR. Manuelof the National Museumof the Philippines, wecould obtain many brachyuran specimens fromthe local shell shermenof Balicasag Island.Some of these specimens provedto belongto anewspecies of the genus Goneplax.Inaddition to this material, some specimens collected from Japanese waters proveto belongto anothernew species of Goneplax. This new species is identical with the species recordedas Goneplax sp. aff. sigsbei by Nagai &Tsuchida(1996) from Miyake-jima I.,Izu Is., andoff Shiono-misaki Cape, Kii Peninsula,central Japan,and was misidentied as G.renoculis byTakeda(1978) fromOshima I.,Izu Is., central Japan.In this paper,we clarify the differences betweenour two new species andtheir congeners,and describe them as newto science. Measurements, givenin millimeters (mm),are ofthe greatest carapacelength andwidth (including the anterolateral teeth), respectively.Pereiopodsare measured alongthe outermargin from ischium to dactylus.The specimens examined are depositedin the Departmentof Zoology, National Science Museum,T okyo (NSMT),the National Museumof the Philippines (NMCR),the Natural History Museumand Institute, Chiba(CBM), and the ShowaMemorial Institute, National Science Museum,T okyo(NSMT S). TAXONOMY Goneplaxmarivenae n.sp.( gs. 1-3, 7A) Materialexamined. — Holotype:male (12 :3 18:2),NSMT -Cr15531, Balicasag I., Bohol, £ Philippines,tangle nets, coll. local shell shermen,February 2003. Paratypes:2 males(11 :7 17:5, 11:4 18:0),1 ovig.female (10 :2 15:7),NSMT -Cr15532, £ £ £ samedata as holotype; 1 male(12 :2 19:1),NMCR, samedata as holotype. £ Description.— Carapace( g. 1a) trapezoidal in generaloutline, 1.5-1.6 times broaderthan long (holotype 1.5 times); uppersurface smoothand glabrous, convex dorsally; regionsill-de ned, marked with H-shapedgroove at center.Frontal region( g. 1b) about0.3 times as broadas carapace,anteriorly slopingdownwards, transversely rectangular; marginsubtruncate, weakly concave medially ,with small mediantriangular tooth,forming almost right anglewith supraorbital margin, TWO NEW GONEPLAX 1245 Fig. 1. Goneplaxmarivenae n.sp.,holotype, male, Balicasag I., Bohol, Philippines, 12 :3 18:2 mm, £ NSMT-Cr15531: a, carapace,dorsal view; b, frontalregion, antero-dorsal view; c, same,frontal view ofleft half with agellumof antennule retracted in fossa and agellumof antenna cut at midway; d,e, right and left chelae (tip of immovable ngerof left chela broken), respectively, external views; f,merus and carpus of cheliped,dorsal view; g, same, lateral view; h-k, left rstto fthambulatory legs,dorsal views. Scales: a, d-g, h-k 2 mm; b, c 1 mm. D D 1246 HIRONORI KOMATSU& MASATSUNET AKEDA markedwith weaksubmarginal line. Lateral marginof carapace moderately convergingposteriorly ,with large,triangular extraorbital toothwith bluntpoint oncorner with supraorbital margin; asmall, acute triangular toothis placedjust behindthe extraorbital tooth,both teeth directed antero-laterally.Posterior margin almost straight, double. Orbit (g. 1a, c): supraorbital marginsinuate, withoutsuture, slightly turned upwards,fringed with veryshort setae; infraorbital marginstraight in mesial half, arcuate in lateral half,slightly turnedupwards. Eyestalk (g. 1c)long, completely set in orbit whenretracted; dorsal extensiononto cornea narrowly rectangular, with roundedtip; corneamuch broader than stalk, 0.4times as longas total eyes- talk. Antennule( g. 1c) transversely foldedinto fossa; basal segment occupying ventral 0.7,with weaktransverse ridgealong midline. Antenna( g. 1c): rst segment transversely ovate; secondand third segments subcylindrical,occupying orbital hiatus; agellum long,slightly longerthan eyestalk. Epistome (g. 1c) triangular, separated frombuccal frame bytransverse ssure. Mandible( g. 2a): endopodwell calcied, with short suture at middle; palpthree- segmented; proximalsegment veryshort; secondsegment fringedwith plumose setae onoutermargin; distal segment entirely fringedwith simple setae. Maxillule (g. 2b): coxal endite elongatetongue-shaped, thin, fringed with short simple setae, with some longplumose setae onproximal part oflower margin; basial endite triangular,fringed with thin andstout simple setae alongmesial margin; endopodtwo-segmented, fringed with plumosesetae alongmesial marginof proximalsegment, distal segment lobularand covering mandible in situ. Maxilla (g. 2c): coxalendite bilobed,both lobes elongatetongue-shaped, fringed with plumosesetae; basial endite distally bilobed,entirely fringedwith simple setae; endopodtriangular, narrowed at tip, fringedwith short plumosesetae excepttip; exopod(scaphognathite) longitudinally ovate, entirely fringedwith short plumose setae. First maxilliped (g. 2d):epipod present; coxalendite rounded,with dense simple setae; basial endite ovate,fringed with simple setae, with submarginalrow ofsimple setae alongmesial margin; endopodlobular, subsquare in distal half, fringedwith plumosesetae alongproximal half ofmesial margin; exopodwith long agellum, agellum fringedwith longplumose setae. Secondmaxilliped (g. 2e): oneepipod and one podobranch present; ischium-merus with submarginal rowof simple setae alonglateral margin; propodusproduced outwards on lateral margin,with simple setae; dactylus with stout setae aroundtip; exopodelongate rectangular,fringed with short plumosesetae alongproximal 0.7 of lateral margin anddistal margin; agellum long,fringed with longplumose setae. Thirdmaxilliped (g. 2f): podobranchpresent; coxaand epipod covering af- ferent channel;basis triangular,fused with ischium butdivided by suture; is- TWO NEW GONEPLAX 1247 Fig. 2. Goneplaxmarivenae n.sp.,holotype, male, Balicasag I., Bohol, Philippines, 12 :3 18:2 mm, £ NSMT-Cr15531. Right mouthparts in external view ,setaeof each agellumof exopod omitted: a,mandible; b, maxillule;c, maxilla; d, rstmaxilliped; e, second maxilliped; f, third maxilliped. Scales:a-e, f 1 mm. D chiumwith shallow obliquegroove at center,dentate andfringed with short se- tae onmesial margin; merus triangularly projectingon mesial margin,dentate on proximalhalf ofmesial margin,produced on disto-lateral corner;palp exposed, fringedwith simple setae oninner margins ofpropodus and dactylus; exopodsub- rectangular,with long agellum fringedwith longplumose setae, with triangu- lar process ondistal 0.3of mesial margin,process concealedbeneath merus in situ. 1248 HIRONORI KOMATSU& MASATSUNET AKEDA Cheliped( g. 1d-g) stout, smooth,2.8-2.9 times as longas carapacein adult male (n 4;holotype2.9 times), 2.5times in adult female (n 1); coxalcondyle D D small, roundedin bothsexes; merus subcylindrical,with small, obtusetriangular toothat proximal0.3 of outermargin of dorsal surface,covered with neattened granuleson innersurface; carpushemispherical, innerangle obtuse in adult male andacute in adult female. Chelae (g. 1d, e) dimorphicin bothsexes, usually right chela slightly