BULLETIN DE L'INSTITUT ROYAL DES SCIENCES NATURELLES DE BELGIQUE, BIOLOGIE, 69: 125-14( '1999 BULLETIN VAN HET KONINKLIJK BELGISCH INSTITUUT VOOR NATUURWETE SCHAPPEN, BIOLOGIE, 69: 125-141, 1999 Pontoniinae (Crustacea: Decapoda: Palaemonidae) associated with bivalve molluscs from Hansa Bay, Papua New Guinea by S. DE GRAVE Abstract many of the shrimp species involved, only two nominal species have been previously recorded from Papua New Eleven species of Pontoniinae (Decapoda: Caridea) are recorded Guinea: Paranchistus armatus (H. MILNE EDWARDS, 1837) as associates from large bivalves in Hansa Bay, Madang Province, was described as Pontonia armata from New Ireland, Papua New Guinea. Nine species are recorded as new to the whilst Anchistus biunguiculatus (BORRADAILE, 1898), a fauna of Papua New Guinea. Morphological details, colour notes junior synonym of P armatus was described from and host records of all species are provided. The taxonomic Tubetube, Engineer group and Anchistus miersi (DE MA , status of Paranchistus pycnodontae Bruce, 1978 in relation to 1888) was recorded by BORRADAILE ( 1900) from Dobu, P. serenei Bruce and P. spondylis Suzuki is discussed. D'Entrecasteaux Islands. No records from the mainland Key words: Caridea, Pontoniinae, Papua New Guinea, of Papua New Guinea are known. Anchioponlonia, Anchistus, Paranchistus, Conchodytes, Bivalve Commensalism with bivalve molluscs is not restricted to associates. pontoniid shrimps, but also occurs in Alpheidae and Atyidae. BANNER & BANNER ( 1968) record Aretopsis Resume amabilis DE MAN, 1910 from a bivalve host (Pterocera sp.) in the Marshall Islands, a species otherwise known to Onze especes de Pontoniinae (Decapoda: Caridea) associees a inhabit gastropod shells, occupied by hermit crabs. NOBILl de larges bivalves ont ete rapportees de Hansa Bay, Province ( 1907) records Synalpheus nilandensis CoUTII':RE, 1905 from de Madang, Papouasie Nouvelle Guinee. Neuf especes sont pearl oysters in the Tuamotu archipelago. HOGARTH (1987) nouvelles pour Ia faune de Papouasie. Des details morpholo records Alpheopsis aequalis CouTII'oRE, 1896 as a commensal giques, Ia couleur ainsi que les hates associes sont fournis pour of Ostrea cristagalli (LINNAEUS) in Oman. The latter two toutes les especes. Le statut taxonomique de Paranchistus pycno records are most likely facultative in nature, as both species dontae Bruce, 1978, en relation avec P. serenei Bruce et P. are widespread in the Indo-Pacific and frequently recorded, spondylis Suzuki est discute. but with no known association with any other invertebrate, Mots cles: Caridea, Pontoniinae, Papouasie Nouvelle Guinee, with the exception of the above records. Perhaps most inter Anchioponlonia, Anchistus, Paranchistus, Conchodytes, Associees de bivalves. esting is the association between the fresh water species, Limnocaridina iridinae ROTH-WOLTERECK and the bivalve mollusc, Iridina spekei WOODWARD in Lake Tanganyika Introduction (ROTH-WOLTERECK, 1958), the only species of commensal atyid shrimp known to date. Commensalism is wide spread amongst tropical shrimp species of the subfamily Pontoniinae (BRUCE, 1976). Both in terms of the number of host species and the number Material and methods of shrimp associates, the most important group of host organisms appears to be Scleractinia (BRUCE, 1977a). Bivalve molluscs were collected from several locations Nevertheless, bivalve molluscs are also important as hosts within Hansa Bay, situated approximately 1O km north of for shrimps. A total of 27 species of Pontoniinae, Bogia, Madang Province, Papua New Guinea. A map of belonging to 8 genera are associated with bivalves in the all the sites sampled is given in CLAEREBOUDT et al. Indo-West Pacific, with a further three species involved ( 1989). Special attention was given to World War II in this association in the East Pacific (FRANSEN, 1995). shipwrecks occurring within the Bay, which proved to be In spite of the wide spread occurrence of this association rich hunting grounds for large bivalves. Molluscs were with bivalves and the wide geographical distribution of placed in mesh bags and returned to the laboratory, where the valves were prised apart and the commensal shrimps extracted. It is interesting to note that all bivalves Contribution no. 30 I of the Leopold III Biological Station, contained at least one individual of commensal shrimp. Laing Island. Post-orbital carapace lengths (cl) are given in mm. I I 126 S. DE GRAVE All specimens have been deposited in the collections of on first four abdominal segments; dorsal white stripe the 'Koninklijk Belgisch Instituut voor Natuurweten running from eye peduncle along base of rostrum to schappen', Brussels, Belgium; registration numbers opposite eye peduncle; egg mass dark orange. Male dark IG 27951 and IG 28056. yellow-orange transparent; dorsal white stripe at base of rostrum present, other white stripes absent. Systematic account DISTRIBUTION Family Palaemonidae RAFINESQUE, I 815 Subfamily Pontoniinae KINGSLEY, 1878 Arno Atoll, Marshall Islands; Raroia Atoll, Tuamotu Islands (HOLTHUIS, 1981); Okinawa, Ryukyu Islands Anchiopontonia BRUCE, 1992 (BRUCE, 1992); Santa! Bay, Loyalty Islands (BRUCE, 1996). Not previously recorded from Papua New Guinea. Anclziopontonia hurii (HOLTHUIS, I 981) Previously reported in association with Spondylus sp. and (Plate Ia) Spondylus varius SOWERBY. Pontonia hurii HOLTHUIS, 1981: 796-800, fig. 4 Anchiopontonia hurii.-BRUCE, 1992: 1276-1282, figs. 1-4. BRUCE, 1996: 204. Anchistus BORRADAILE, 1898 Anchistus australis BRUCE, 1977 MATERIAL (Fig. 1) 1 female (cl4.7) 1 male (cl 3.8) KBIN IG 27951/NAT15; Davit Anchistus australis forma typica BRUCE, 1977b: 56-62, figs. 7-9. Wreck, Hansa Bay, 9m depth, from Spondylus varius, leg. S. Anchistus australis forma dendricauda BRUCE, 1977b: 62, fig. 10. DE GRAVE, 5 October 1992, field no. S92/127. 1 male (cl 3.9) Anchistus australis. - BRUCE, 1980a: 395-396, fig. 3A. - KBIN IG 27951/NAT16; Sushi Maru Wreck, Hansa Bay, 19m BRUCE, 1983a: 892, fig. 1O A. depth, from Spondylus varius, leg S. DE GRAVE, 7 October 1992, field no. S92/133. 1 ov. female (cl 5.2) 1 male (cl 3.6) KBIN IG 27951/NATI7; Davit Wreck, Hansa Bay, !Om depth, from MATERIAL Spondylus varius, leg. S. DE GRAVE, 14 October 1992, field no. S92/153. I ov. female (cl 6.0) I male (cl 4.6) KBIN JG I female (cl 3.4), I juvenile (cl 1.5) KBIN IG 28056/NAT20; 28056/NAT 18; Laing Island outer reef slope, 20m depth, from Laing Island lagoon, rubble slope, 5m depth, from Hippopus Spondylus varius, leg. S. DE GRAVE, 30 September 1993, field hippopus, leg. S. DE GRAVE, 28 September 1993, field no. no. S93/39. I ov. female (cl 5.2) 1 male (cl 3.3) KBIN JG S93/25. 1 ov. female (cl 6.1 ), 1 male ( cl 4.2) KBIN IG 28056/NAT 19; Laing Island outer reef slope, 15m depth, from 28056/NAT21; Laing Island reef slope, 15m depth, from Tridacna Spondylus varius, leg. S. DE GRAVE, 9 October 1993, field no. squamosa, leg. J.-M. TERNATE, 10 October 1993, field no. S93/85. S93/82. 1 juv. (cl 1.6) KBIN IG 28056/NAT22; Laing Island reef slope, !Om depth, from Tridacna gigas, leg. P. VAN DE WALLE, 12 October 1993, field no. S93/100. 1 ov. female (cl 5.5), 1 male REMARKS (cl 3.8) KBIN IG 28056/NAT23; Laing Island reef slope, 7m depth, from Tridacna squamosa, leg. H. WILKINS, 20 October The present specimens agree closely with the previous 1993, field no. S93/129. descriptions of this species by HOLTHUIS (1981) and BRUCE ( 1992), with the laterally mobile tel son spines and the shape of the dactyl being highly diagnostic. As in the REMARKS specimen described by BRUCE (1992), a minute pre.: terminal ventral tooth is present on the rostrum in all of Most specimens have a rostral dentition of 511 or 6/1 the present specimens, with the exception of one female (Fig. 1 a, b), with one non-ovigerous female having (KBIN IG 28056/NATI 9). One male specimen has a 2 minute ventral teeth (KBIN IG 28056/NAT20), whilst regenerating tip of the rostrum with no teeth being present the rostral tip appears bifid in one ov. female (KBIN (KBIN IG 28056/NAT 19), whilst in one male (KBIN IG IG 28056/NAT23). As in the material of FRANSEN ( 1995) 28056/NAT 16) the acute tip of the rostrum is missing, the rostral dentition in juveniles extends over a slightly creating a truncate appearance. As already noted by BRUCE longer distance than in adults. In the present material, (1992), the dactylar accessory spine of the ambulatory the accessory spine on the dactylus of the third pereiopod pereiopods is serrulate (Plate 1a ). is reduced, and a single small spine is present along the disto-ventral margin of the pro pod us (Fig. I d), as COLOUR opposed to two described in the type material (BRUCE, 1977b). The submedian terminal telson spines are non Female largely transparent with dark yellow-orange hue, plumose, as opposed to sparsely plumose in the type one narrow white stripe on carapace and one similar stripe material. However, significant variation exists in telson '. Pontoniinae from Papua New Guinea 127 spination in this species (see BRUCE, 1977b), both in COLOUR terms of the dorsal and the terminal spines (Fig. I f). The endopod of the male first pleopod, although similar Generally transparent, with scattered small blue dots all in general appearance to the illustration and descrip over the body and the appendages. tions by BRUCE (1977b), harbours more plumose setae along its lateral border and more non-plumose setae along its medial border, whilst in addition a small lobe DISTRIBUTION is present at the distal part of the medial border (Fig. !g). The appendix masculina harbours more sub-terminal Swain's Reef, Michael mas Reef, Heron Island and Port setae than in BRUCE (1977b) . Essington, Australia (BRUCE & COOMBES, 1995); Ndravuni h Fig. I - Anchistus australis BRUCE. KBIN IG 28056/NAT21. a: carapace of female; b: carapace of male; c: third pereiopod; d: detail of third pereiopod; e: terminal region of telson of female; f: terminal region of telson of male; g: male first pleopod; h: male second pleopod; i: appendices masculina and interna of male second pleopod. a, e female ( c1 6.1 ), remainder from male (cl 4.2). Scale bars indicate I mm (a-c), 0.5 mm (d-h) or 0.1 mm (i). II 128 S. DE GRAVE Island, Fiji (BRUCE, 1980a); Seram Island, Ambon, MATERIAL Indonesia (BRUCE, 1983a; FRANSEN, 1995); Enewetak, Marshall Islands (DEVANEY & BRUCE, 1987); baie I ov. female (cl7.4), I male (cl4.1) KBIN IG 27951/NAT24; d'Harcourt, New Caledonia (BRUCE, 1991); Tre Island, Laing Island lagoon, 6m depth, from Atrina vexillum, leg. S. Vietnam (BRUCE, 1993 ). Not previously reported from DE GRAVE, 2 September 1992, field no. $92116. 2 ov. females Papua New Guinea. Previously reported in association (cl 8.2-9.0), 2 males (cl 3.1-4.6) KBIN IG 27951/NAT25; Laing Island reef slope, 15m depth, from Pinna bicolor, leg. S. DE with Tridacna sp., Tridacna squamosa LAMARCK and GRAVE, 6 September 1992, field no. S92.'31. 2 ov. females (cl T. derasa (RODING), the present assocations with Hippopus 8.3-9.2), 2 males (cl 4.3-4.7) KBIN IG 27951/NAT26; Laing hippopus LINNAEUS and Tridacna gigas LlNNAEUS present Island lagoon, 7m depth, from Atrina ve.xillum, leg. S. DE GRAVE, new host records. 12 October 1992, field no. S92/150. I ov. female (cl 8.6), 1 male (cl 4.5) KBIN IG 28056/NAT27; Laing Island lagoon, 5m depth, from Atrina vexillum, leg. S. DE GRAVE, 28 September Anchistus custoides BRUCE, 1977 1993, field no. S93/24. I ov. female (cl 8.2), 1 male (cl 3.8) (Fig. 2) KBIN IG 28056/NAT28; Laing Island reef slope, from Atrina vexillum, leg. P. VAN DE WALLE, 30 September 1993, field no. Anchistus custoic/es BRUCE, 1977b: 50-56, figs. 4-6. S93/35. I ov. female (cl 8.0) I male (cl5.1) KBIN 28056/NAT64; Anchistus inermis. - Kuso, 1940: 48-51, figs. 15-17 (not Laing Island lagoon, from Atrina vexillum, leg. J.-M. TERNATE, Harpilius inermis MIERS). September 1993, field no S93/138. a d --b,c ---e,f -----a,c c Fig. 2 - Anchistus custoic/es BRUCE. KBIN 28056/NAT28. a: frontal region of carapace; b: terminal region of telson; c: carpus of second pereiopod; d: distal region of third pereiopod; e: endopod of second pleopod; f: appendices masculina and interna of second pleopod. a, c from female (cl 8.2), remainder from male (cl 3.8). Scale bars indicate I mm (a, c), 0.25 mm (b), or 0.1 mm (d, e, f). '' Pontoniinae from Papua New Guinea 129 REMARKS DISTRIBU1'ION The present specimens agree closely with the previous Palau (Kuao, 1940); Swain Reefs, Heron Island, One Tree descriptions of BRUCE (1977b) and Kuao (1940). Minor Island, Australia (BRUCE, 1981 ); Ryukyu Islands (MIYAKE, differences were noted in the position of the antenna) 1982); Seram Island, Indonesia (BRUCE, 1.983a); Tre Island, spine in relation to the inferior orbital angle (Fig. 2a), Vietnam (BRUCE, 1993). Not previously reported from the intermediate terminal telson spines being less swollen Papua New Guinea. Previously reported in association than indicated by BRUCE (1977b), whilst the cutting edges with Magnavicula sp., Pinna sp. and AtJ·ina vexillum of the chelae of the second pereiopod resemble the illus (BORN), the present assnciation with Pinna bicolor GMELIN tration by Kuao ( 1940) more than the illustration by BRUCE is a new host record. (1977b ). Both the endopod of the first male pleopod and the appendix masculina closely resemble those in BRUCE ( 1977b) , although the setae along the lateral margin of Anchistus custos (FORSSKAL, 1775) the endopod of the first pleopod are non plumose. (Fig. 3, Plate I b-e) Cancer custos FORSSKAL, 1775: 94. COLOUR Anchistus custos. - HOLTHUIS, 1952: 105-109, figs.43-44. - Generally transparent, with scattered orange dots all over BRUCE, 1982: 264-265, fig. 19. body and appendages. a e d Fig. 3 - Anchistus custos (FORSSKAL). KBIN IG 2795 I/NAT29. a: endopod of male first pleopod; b: appendices masculina and interna of male second pleopod; c: detail of third pereiopod (male); d: rostrum of male; e: rostrum of female. Scale bar indicates I mm (d-e) or 0.2 mm (a-c). '' 130 S. DE GRAVE Plate I - Anchiopontonia hurii KBIN IG 27951/NAT 17, male (cl 3.6); a: accessory spine on dactylus of third pereiopod (2020x). Anchistus custos KBIN IG 27951/NAT29, male (cl 6.5); b: dactylus of third pereiopod (137x); c: detail of dorsal smface (31O Ox). Anchistus miersi KBIN IG 28056/NAT38, male (cl 5.2); d: dactylus of third pereiopod (600x); e: detail of multidenticulate setules (6750x). Conchodytes melaegrinea KBIN IG 27951/NAT41, male (cl 6.1) ; f: dactylus of third pereiopod (186x); g: detail of dorsal surface (2980x). Conchodytes monodactylus KBIN IG 27951/NAT55, male (cl 6.7); h: dactylus of third pereopod (137x). Pontoniinae from Papua New Guinea 131 a b --a,b ---c,e,h ---d,f-g.i-k 9 f Fig. 4 - Anchistus demani KEMP. KBfN IG 27951/NAT31. a: carapace of female; b: carapace of male; c: second pereiopod; d: detail of second pereiopod; e: third pereiopod; f: detail of third pereiopod; g: telson; h: first pereiopod; i: third maxil liped; j: endopod of male first pleopod; k: appendices masculina and interna of male endopod of second pleopod. a, c-i from female (cl 4.1 ), remainder from male (cl 2.2). Scale bars indicate 1 mm (a, b), 0.5 mm (c, e, h), 0.2 m111 (d, i, g), 0.1 111m U, k) or 0.05 m111 (f). 132 S. DE GRAVE MATERIAL October 1992, field no. S92/ 128. I ov. female ( c1 2.0) KBIN IG 27951/NAT34; Davit Wreck, Hansa Bay, 3m depth, from Tridacna I ov. female (cl 9.1), I male (cl 6.5) KBIN IG 27951/NAT29; maxima, leg. H. WILKINS, 5 October 1992, field no. S92/129. Sushi Maru Wreck, Hansa Bay, 19m depth, from Pinna bicolor, leg. D. VANDERSPIEGEL, 2 September 1992, field no. S92/17. REMARKS REMARKS Rostrum truncate with two dorsal teeth (Fig. 4a, b), except one ovigerous female (KBIN IG 27951/NAT34) which The present specimens agree with previous descriptions harbours a single tooth; rostrum in males ascending in (HOLTHUIS, 1952; BRUCE, 1982), with the cannulate palm distal half (Fig. 4b), in females nearly straight (Fig 4a). of the chelae of the first pereiopods being highly charac Dentition of fixed finger and dactylus of second pereiopod teristic. Both specimens have a minute tubercle at the less pronounced (Fig. 4d) than described in the type fronto-dorsal margin of the rostrum (Fig. 3d, e). The general material (KEMP, 1922). Accessory tooth on dactylus of appearance of the endopod of the male first pleopod third pereiopod blunt and inconspicuous (Fig. 4f). appears to be subject to some variation, with in the present Distoventral angle of propodus with pair of small spines material a distal, prominent protruberance being present (Fig. 4 f), these being noted as absent by KEMP ( 1922) in along the medial margin (Fig.3a) (see HOLTHUIS, 1952; the type material, but probably overlooked (see BRUCE, BRUCE, 1982). In the male, the appendix masculina reaches 1991 ). Dorsal surface of dactylus covered with micro to the end of the appendix interna and is furnished with scales, with three pairs of short setae below this area (Fig. numerous setae along its medial and lateral margins (Fig. 4f). Distance between dorsal pairs of telson spines approx 3b). SEM observations revealed that the dorsal surface imately twice as long as distance between posterior pair of the dactylar corpus of the ambulatory pereiopods is and apex (Fig. 4g). Endopod of male first pleopod (Fig. furnished with minute, scattered scales (Plate 1b -e). 4j) with prominent lobe along medial margin and a series of plumose setae along lateral margin. Appendix masculina only half the length of the appendix interna and sparsely COLOUR furnished with long setae in distal part (Fig. 4k). Generally transparent, with scattered yellow-orange dots all over body and appendages. COLOUR Generally transparent with scattered blue dots all over DISTRIBUTION body, less numerous on legs. Ova green. Wide spread in the Indo-Pacific, ranging from the Red Sea and East Africa to Australia and Fiji (HOLTHUIS, 1952; CHACE & BRUCE, 1993). Not previously reported from DISTRIBUTION Papua New Guinea. Mainly associated with species of Pinna (Mollusca: Pinnidae). Wide spread in the Indo-Pacific, ranging from East Africa to Australia and the Marshall Islands (CHACE & BRUCE, 1993). Not previously reported from Papua New Guinea. Anchistus demani KEMP, 1922 Previously reported in association with Tridacna sp., (Fig. 4) Tridacna crocea LAMARCK, T maxima (RbDlNG) and T gigas L., the preseot association with T squamosa is Anchistus demani KEMP, 1922: 256-259, figs. 86-88. a new host record. Anchistus demani.- BRUCE, 1974: 200-201.- BRUCE, 1977b: 50. - BRUCE, 1991: 259-260, fig. 22. Anchistus miersi (DE MAN, 1888) (Plate 1d -e) MATERIAL Harpilius miersi DE MAN, 1888: 274-277, Plate 17: figs. 6-10. I ov. female (cl 3.2), I male (cl 2.1) KBIN IG 28056/NAT30; Anchistus miersi. - HOLTHUIS, 1952: 110-111, fig. 45. - BRUCE, Laing Island reef slope, 5m depth, from Tridacna sp., leg. S. DE 1973: 136, fig. Ic-e.- MONOD, 1976: 24-26; figs. 29-36. GRAVE, 7 October 1993, field no. S93/72. I ov. female (cl 4.1 ), I male (cl 2.2) KBIN IG 27951/NAT31; Laing Island lagoon, 6m depth, from Tridacna maxima, leg. J-M. OUIN, 2 September 1992, MATERIAL field no. S92/18. l non-ov. female (cl2.5) KBIN IG 27951/NAT32; Laing Island lagoon, 5m depth, from Tridacna squamosa, leg. S. l ov. female (cl 3.6) KBIN IG 27951/NAT35; Sushi Maru DE GRAVE, 17 September 1992, field no. S92/67. I ov. female (cl Wreck, Hansa Bay, 19m depth, from Magnavicula penguin, leg. 3.0), I male (cl2.0) KBIN IG 27951/NAT33; Davit Wreck, Hansa S. DE GRAVE, 29 September 1992, field no. S92/7. l ov. female Bay, 3m depth, from Tridacna squamosa, leg. S. DE GRAVE, 5 (cl 3.5), l male (cl 2.1) KBIN IG 27951/NAT36; Laing lsi reef 'I Pontoniinae from Papua New Guinea 133 flat, intertidal, from T. maxima, leg. S. DE GRAVE, 6 October REMARKS 1992, field no. S92/32. I male (cl 3.1) KBIN IG 27951/NAT37; Davit Wreck, Han sa Bay, I Om depth, from Magnavicula penguin, The present specimens agree with the description of leg. S. DE GRAVE, 14 October 1992, field no. S92/156. I ov. FRANSEN ( 1994) in having a single serrate, broad tooth female (cl 6.6), I male (cl 5.2) KBIN IG 28056/NAT38; Duangit on the dactylus of the second pereiopod anc;l two serrate, reef, Hansa Bay, 3m depth, from Tridacna sp., leg. S. DE GRAVE, broad teeth on the fixed finger. In contrast, the rostrum 12 October 1993, field no. S93/101. I ov. female (cl 4.0), I is more broadly triangular and the basal protuberance on male (cl 3.1) KBTN IG 28056/NAT39; Laing Island reef slope, the dactylus of the third pereiopod is not wdl developed, 5m depth, from Tridacna sp., leg. H. WILKINS, 20 October 1993, the latter is furnished wit!:! a small tooth. The accessory field no. S93/130. I juvenile (cl 2.2) KBIN IG 28056/NAT64, tooth is small, approximately 0.3 x length of primary free in Laing Island aquarium, leg. S. DE GRAVE, 30 September unguis. Unguis well demarcated from corpus, with trans 1993, field no. S93/42. verse striations. REMARKS COLOUR The specimens agree closely with previous descriptions. Not noted in live specimens. Rostral dentition is 4-5/0-1, with the ventral tooth reduced to a tubercle in some specimens. In juveniles, the rostral dentition extends over a slightly longer distance. SEM observations revealed that the dactylar accessory tooth is DISTRIBUTION serrated (Plate 1d ), whilst the dorsal surface of the dactylus is covered with multidenticulate setules (Plate 1e ). Due to confusion regarding the identity of C. biunguic ulatus versus C. nipponensis (DE HAAN, 1844), the distri bution of this taxon is not clear. With certainty, the species is known from the Indian Ocean (FRANSEN, 1994), COLOUR Indonesia, southern Taiwan (HOLTHUIS, 1952) and Vietnam Generally transparent, with scattered red dots all over (BRUCE, 1993). Not previously reported from Papua New body and appendages. Guinea. The association with S. saccata is a new host record. DISTRIBUTION Conchodytes meleagrinae PETERS, 1852 Wide spread in the Indo-Pacific, ranging from the Red (Plate 1f -g) Sea to French Polynesia (CHACE & BRUCE, 1993 ). Previously found in Papua New Guinea: Dobu, Conchodytes meleagrinae PETERS, 1852: 289-290. D'Entrecasteaux group (BORRADAILE, 1900). Mainly in Conchodytes meleagrina.e- BORRADAILE, 1917: 393, Plate 57, fig. 26. - KEMP, 1922: 285.- BRUCE, 1977b: 73, fig. l4c-d. association with the genera Hippopus and Tridacna. - BRUCE, 1991: 262, fig. a-d. Although the association with the genus Magnavicula is considered doubtful by CHACE & BRUCE (1993) and FRANSEN (1995), the present records substantiate this MATERIAL association. I ov. female (cl 7.1), I male (cl 5.7) KBIN IG 27951/NAT40; Laing Island lagoon, 15m depth, from Pinctada margaritifera, Conchodytes PETERS, 1852 leg J.-M. OUIN, 3 September 1992, field no. S92/29. 3 ov. females (cl 6.7-7.3) I non ov. female (cl 6.4) 6 males (cl 5.0- Conchodytes biunguiculatus (PAuL'soN, 1875) 6.1) KBIN IG 27951/NAT41; Laing Island lagoon, !Om depth, from Pinctada margaritifera, leg. S. DE GRAVE, 29 September Pontonia biunguiculatus PAUL' SON, 1875: Ill, Plate 15, fig. I. 1992, field no. S92/4. I non ov. female (cl 8.0), I male (cl Conchodytes biunguiculatus. - HOLTHUIS, 1952: 199-200. - 6.1) KBIN IG 27951/NAT42; Laing Island lagoon, I Om depth, FRANSEN, 1994: 89-96, figs. 3-7, 12-15, 23, 27, 30-31, 35. from Pinctada margaritifera, leg. S. DE GRAVE, 29 September Conchodytes kempi BRUCE, 1989: 183-184, fig. 3b-e. 1992, field no. S92/5. 15 spec. (cl 2.0-8.2) KBIN IG Conchodytes kempi. - BRUCE, 1993: 60-61, fig. 4. 27951/NAT43; Lagoon Wreck, Laing Island, from Pinctada margaritifera, leg. J.-M. OuJN, 31 September 1992, field no. S92/IO. 1 ov. female (cl 6.7), I male (cl 4.8) KBIN IG MATERIAL 27951/NAT44; Laing Island lagoon, from Pinctada margari tifera, leg. J.-M. OUIN, 6 September 1992, field no. S92/33. 1 ov. female (cl 4.6), I male (cl 2.9) KBIN IG 27951/NAT65; 2 males (cl 6.9, 7.0) KBIN IG 27951/NAT45; Lagoon Wreck, Laing lsi lagoon, rubble slope, 7m depth, from Streptopinna saccata Laing Island, from Pinctada margaritijera, leg. D. VANDERSPIEGEL, (L.) partly embedded in atrial cavity of large unidentified sponge, 7 September 1992, field no. S92/44. I ov. female (cl 7.9) leg. S. DE GRAVE, II October 1992, field no. S921145. 3 males (cl 5.0-6.1) KBIN IG 27951/NAT46; Riverwreck, Hansa 134 S. DE GRAVE Bay, 9m depth, from Pinctada margaritifera, leg. S. DE GRAVE, REMARKS 8 September 1992, field no. S92/51. I ov. female (cl 8.6), I male (cl 5.5) KBIN IG 27951/NAT47; Duangit Reef, Hansa Rostrum broadly triangular in dorsal view (Fig. Sa), Bay, I Om depth, from Pinctada margaritifera, leg. J.-M. OUIN, reaching to end of third segment of antennular peduncle; 20 September 1992, field no. S92/86. 1 ov. female (cl 7.0), I apex broadly rounded in both dorsal and lateral view (Figs. male (cl 5.5) KBIN IG 27951/NAT48; Laing Island lagoon, Sa, b). Inferior orbital angle distinctly produced. Telson from Pinctada margaritifera, leg. S. DE GRAVE, II October 1992, 1.8 x longer than wide, with pairs of strong spines inserted field no. S921143. 1 ov. female (cl 8.7), 1 male (cl 6.4) KBfN at 0.23 and 0.70 of length (Fig. 5d}. Apex with pair of IG 27951/NAT49; Laing Island lagoon, from Pinctada margar sub-terminal spines and two pairs of terminal spines; outer itifera, leg. S. DE GRAVE, 11 October 1992, field no. S92/144. pair of terminal spines larger than thinner, curved inner I female (cl 7.5), I male (cl 5.1) KBIN IG 27951/NAT50; pair (Fig. 5e); inner pair with scales along part of medial Laing Island reef flat, intertidal margin, 0.5m, from Pinctada margin (Fig. 5t). Antenna! scale (Fig. Sh) and third maxil margaritifera leg. H. WILKINS, 14 October 1992, field no. S92/155 liped (Fig. 5g) as described by HOLTHUIS (19S2), although . I female (cl I 0.5) KBIN IG 28056/NAT51; Laing Island the antepenultimate segment of the latter is narrower. lagoon, from Pinctada maxima, leg. P. VAN DE WALLE, 23 Second pereiopods large, reaching beyond scaphocerite; September 1993, field no. S93/6. I ov. female (cl 5.5), 2 males dactylar tip strongly curved, both fixed finger and dactylus (cl 4.6, 6.5) KBIN IG 28056/NAT52; Laing Island reef slope, with single, broad tooth (Fig. 5c). Third pereiopod stout from Pinctada margaritifera, leg. P. VAN DE WALLE, 30 September (Fig. 5i); ischium 0.85 x length of merus; carpus 0.76 x 1993, field no. S93/36. 1 ov. female (cl 8.3), I male (cl 5.8) length of propodus; dactylus with well developed basal KBIN IG 28056/NAT53; Laing Island reef slope, 5m depth, protuberance, unguis demarcated from corpus (Fig. 5j, from Pinctada margaritifera, leg. S. DE GRAVE, 7 October 1993, Plate I h). Male first pleopod with endopod 0.4 x length field no. S93/70. I ov. female (cl 8.1), I male (cl 6.4) KBIN of exopod; endopod furnished with plumose setae along IG 28056/NAT54; Laing Island reef slope, !Om depth, from both medial and lateral margin, extending further along Pinctada margaritifera, leg. S. DE GRAVE, 7 October 1993, field medial margin (Fig. 5k). Male second pleopod with no. S93/71. endopod 0.89 x length of exopod, appendices inserted at 0.24 of endopod. Appendix masculina 0.74 x length of appendix interna, furnished with progressively longer setae REMARKS along medial margin and apex (Fig. 51). The present specimens agree in most respects with the type description The present specimens present no unique features. SEM by HoLTHUIS ( 19S2) and can be separated from all other observations showed that the dorsal surface of the dactylar Conchodytes species by the lack of an accessory tooth on unguis of the ambulatory pereiopods is covered with trans the dactyl of the ambulatory pereiopods. verse rows of minute, pointed scales (Plate If-g). COLOUR COLOUR Colour not noted in living specimens. Transparent with scattered orange dots. DISTRIBUTION Distribution Lesser Sunda Islands, Indonesia; southern Taiwan Wide spread in the Indo-Pacific, ranging from the Red (HoLTHUIS, 1952); Singapore (JOHNSON, 1961 ); Magnetic Sea to French Polynesia (CHACE & BRUCE, 1993 ). Not Island and Cobourg Pe.ninsula, Australia (BRUCE, 1977c; previously reported from Papua New Guinea. Always in 1983b ); Hong Kong (BRUCE, 1979). Not previously reported association with the genus Pinctada (FRANSEN, 1995). from Papua New Guinea. Previously reported in associ ation with Pinna sp., Pinna bicolor and Atf·ina sp., the present association with M penguin is a new host record. Conchodytes monodactylus HOLTHUIS, 1952 (Fig. 5, Plate 1h ) Paranchistus HOLTHUIS, 1952 Conhodytes monodactylus HOLTHUIS, 1952: 200-204, figs. 96-98. Conchodytes monodactylus. - BRUCE, 1977c: 177-178, fig. 8. Paranchistus armatus (H. MILNE EDWARDS, 183 7) (Plate 2a) MATERIAL Pontonia armata H. MILNE EDWARDS, 1837: 359. Paranchistus annatus. - BRUCE, 1975: 49, figs. 1-3. I ov. female (cl 10.6), I male (cl 6.7) KBIN !G 27951/NAT55; Anchistus biunguicu!atus BORRADAILE, 1898: 387. Lagoon Wreck, Laing Island, 20m depth, from Magnavicula Paranchistus biunguiculatus. - HOLTHUIS, 1952: 93-97, figs. penguin, leg. J.-M. OuiN, 7 September 1993, field no. S92/43 36-38.