TWONEWSPECIESOF 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 Ž 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 Ž vespecies fromthe Indo-PaciŽc (Serène & Umali, 1972),viz., G.sinuatifrons Miers, 1886, G.maldivensis Rathbun,1902, G.renoculis Rathbun,1914, G. wolŽ 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) clariŽ 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 aŽeld trip to Balicasag Island, Bohol,Philippines, as apart ofaresearch project ofthe National Science Museum, Tokyo,entitled “Natural History ofthe West PaciŽc Archipelago”. Onthis, arrangedby Ms. MariveneR. Manuelof the National Museumof the Philippines, wecould obtain many brachyuran specimens fromthe local shell Žshermenof Balicasag Island.Some of these specimens provedto belongto a newspecies 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.,IzuIs., andoff Shiono-misaki Cape, Kii Peninsula,central Japan,and was misidentiŽed 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.(Ž gs. 1-3, 7A)

Materialexamined. — Holotype:male (12 :3 18:2),NSMT -Cr15531, Balicasag I., Bohol, £ Philippines,tangle nets, coll. local shell Ž 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(Ž g. 1a) trapezoidal ingeneral outline, 1.5-1.6 times broaderthan long (holotype 1.5 times); uppersurface smoothand glabrous, convex dorsally; regionsill-deŽ ned, marked with H-shaped groove at center.Frontal region(Ž g. 1b) about0.3 times as broadas carapace,anteriorly slopingdownwards, transversely rectangular; marginsubtruncate, weakly concave medially ,withsmall mediantriangular tooth,forming almost right anglewith supraorbital margin,