DEEP-WATER PECTINOI D EA 77 New species and new records of deep-water Pectinoidea (Bivalvia: Propeamussiidae, Entoliidae and Pectinidae) from the South Pacific Henk H. DIJKSTRA & Philippe MAESTRATI Zoological Museum, University of Amsterdam, Mauritskade 61, 1092 AD Amsterdam, The Netherlands [email protected] Muséum national d’Histoire naturelle, Département Systématique & Évolution, CP 51, 55 Rue de Buffon, 75005 Paris, France [email protected] ABSTRACT Fifty-two deep-water species of Pectinoidea (37 Propeamussiidae, 1 Entoliidae, 14 Pectinidae) are listed from Norfolk Ridge (11 species), Loyalty Islands (4 species), Fiji Islands (30 species), Tonga (26 species), Solomon Islands (26 species) and the Marquesas archipelago (8 species). All species from Fiji, Tonga and the Marquesas are new records and six species of Propeamussiidae are new to science: Propeamussium boucheti (Fiji and Tonga), Parvamussium biformatum (Solomons), Parvamussium lozoueti (Fiji and Tonga), Parvamussium marquesanum (Marquesas), Parvamussium polynesianum (Marquesas) and Similipecten herosae (Tonga). Two new combinations (Hyalopecten tydemani, Talochlamys gladysiae) are introduced. RÉSUMÉ Pectinoidea (Bivalvia : Propeamussiidae, Entoliidae et Pectinidae) des eaux profondes du Pacifique sud : espèces et occurences nouvelles. Cinquante deux espèces profondes de Pectinoidea (37 Propeamussiidae, 1 Entoliidae, 14 Pectinidae) ont été reconnues de la Ride de Norfolk (11 espèces), des Iles Loyauté (4 espèces), des Iles Fidji (30 espèces), des Iles Tonga (26 espèces), des Iles Salomon (26 espèces) et des Iles Marquises (8 espèces). Toutes les espèces des Fidji, Tonga et Marquises représentent des occurences nou- velles. Six nouvelles espèces de Propeamussiidae sont décrites : Propeamussium boucheti (Fidji et Tonga), Parvamussium biformatum (Salomon), Parvamussium lozoueti (Fidji et Tonga), Parvamussium marquesanum (Marquises), Parvamussium polynesianum (Marquises) et Similipecten herosae (Tonga). Deux nouvelles combinaisons (Hyalopecten tydemani, Talochlamys gladysiae) sont établies. DIJKSTRA H. H. & MAESTRATI P. 2008. — New species and new records of deep-water Pectinoidea (Bivalvia: Propeamussiidae, Entoliidae and Pectinidae) from the South Pacific, in HÉROS V., COWIE R. H. & BOUCHET P. (eds), Tropical Deep-Sea Benthos 25. Mémoires du Muséum national d’Histoire naturelle 196: 77-113. Paris ISBN: 978-2-85653-614-8. 78 HENK H. DIJKSTRA & PHILIPPE MAESTRATI INTRODUCTION This paper deals with new species and records of deep-water, Recent pectinoids from several French cruises (1997- 2000) to the Loyalty Islands (ATELIER LIFOU 2000), Fiji Islands (MUSORSTOM 10, BORDAU 1), Tonga (BOR- DAU 2) and the Marquesas Islands (MUSORSTOM 9). For the context and narratives of these expeditions, see the introductory chapter by Bouchet et al. (this volume). The species mentioned in earlier publications (Dijkstra 1989b; 1990a; 1990b; 1991; 1995; 2001; Dijkstra and Kastoro 1997; Dijkstra and Marshall 1997; Dijkstra and Kilburn 2001) are briefly reported but not refigured and previously known shallow water pectinids (down to c. 50 m depth) from French Polynesia (Dijkstra 1989a; 2002) are not dealt with. All studied material is deposited in the Muséum national d’Histoire naturelle (MNHN) in Paris, with the exception of voucher specimens in the private pectinoid reference collection of the senior author. Repositories BMNH: The Natural History Museum, London HD: H. H. Dijkstra collection HPW: H. P. Wagner collection MNHN: Muséum national d’Histoire naturelle, Paris NMW: National Museum of Wales, Cardiff ZMA: Zoological Museum, University of Amsterdam, Amsterdam ZMB: Museum für Naturkunde, Humboldt-Universität, Berlin ZMUC: Zoological Museum, University of Copenhagen, Copenhagen. Abbreviations lv: left valve(s) rv: right valve(s) v: valve(s) spm(s): live-taken specimen(s) H: height (dorsal-ventral) in mm L: length (anterior-posterior) in mm D: diameter (convexity, or maximum combined thickness of both articulated valves) in mm. SYSTEMATIC ACCOUNT Superfamily PECTINOIDEA Rafinesque, 1815 REMARKS. — The superfamily Pectinoidea and family Pectinidae were previously attributed to Wilkes (1810). However, the chapter by Wilkes (1810) is not entirely binominal and therefore unavailable according to the Code (ICZN 1999). Family PROPEAMUSSIIDAE Abbott, 1954 Genus PROPEAMUSSIUM de Gregorio, 1884 Propeamussium alcocki (Smith, 1894) Amussium alcocki Smith, 1894: 172, pl. 5, figs 15-16. DEEP-WATER PECTINOI D EA 79 MATERIAL EXAMINED. — The type material (see Dijkstra 1995: 33 spms; stn CP 1415, 16˚31’S, 179˚00’W, 670-682 m, 1 spm; 13, figs 133-137). stn CP 1460, 18˚47’S, 178˚47’W, 750-767 m, 2 spms; stn CP Solomon. SALOMON 1: stn CP 1750, 09°15.6’S, 159°54.6’E, 1491, 18˚50’S, 178˚27’W, 777-787 m, 2 spms; stn CP 1502, 693-696 m, 3 lv; stn CP 1751, 09°10.4’S, 159°53.0’E, 749-799 18˚21’S, 178˚27’W, 640-660 m, 2 spms; stn CP 1504, 18˚13’S, m, 1 lv; stn CP 1753, 09°02.7’S, 159°49.4’E, 1001-1012 m, 178˚34’W, 427-440 m, 1 spm. 4 spms. Tonga. BORDAU 2: stn CP 1625, 23˚28’S, 176˚22’W, 824 m, Fiji. BORDAU 1: stn CP 1413, 16˚10’S, 179˚24’W, 669-676 m, 6 spms. DISTRIBUTION. — Gulf of Aden, Laccadive Sea, Bay of Bengal, Chesterfield Islands, New Caledonia, Loyalty Islands (Dijkstra 1995: 13), Indonesia (Dijkstra & Kastoro 1997: 247), Norfolk Island (Dijkstra & Marshall 1997: 74), Wallis and Futuna and Vanuatu (Dijkstra 2001: 74); live in 750-1353 m. New records for the Solomon Islands, Fiji and Tonga. Present material live in 440-1001 m. REMARKS. — The present material is similar to the type specimens, although somewhat darker in colour (brownish, whitish is typical) and slightly more elongate (type specimens nearly circular). Propeamussium andamanicum (Smith, 1894) Amussium andamanicum Smith, 1894: 172, pl. 5, figs 13-14. MATERIAL EXAMINED. — The type material (see Dijkstra 1995: m, 38 spms. — BORDAU 1: stn CP 1398, 16˚22’S, 179˚56’W, 15, figs 138-142). 907-912 m, 3 spms; stn CP 1458, 17˚22’S, 179˚28’W, 1216- Fiji. MUSORSTOM 10: stn CP 1354, 17˚42.6’S, 178˚55.0’E, 959- 1226 m, 21 spms. 963 m, 85 spms; stn CP 1361, 18˚00.0’S, 178˚53.7’E, 1058-1091 DISTRIBUTION. — Zanzibar area, Gulf of Aden, Arabian Sea, Laccadive Sea, Andaman Sea, New Caledonia (Dijkstra 1995: 15), Wallis and Futuna and Vanuatu (Dijkstra 2001: 75); live in 956-2000 m. New record for Fiji. Present ma- terial live in 912-1216 m. This species seems to occur rather abundantly around Fiji, in contrast to other known loca- lities in the southwestern Pacific. REMARKS. — The present material is almost identical to the type specimens, except that the commarginal lirae on the left valve are more delicate and more closely spaced. Propeamussium boucheti n. sp. Figs 1-4 TYPE MATERIAL. — Holotype (spm) MNHN 20441 and 25 paratypes MNHN 20442-20447, 2 HD. TYPE LOCALITY. — Fiji, Bligh Water, 16˚52.51’S, 177˚43.66’E, 500-614 m [MUSORSTOM 10: stn CP 1341]. MATERIAL EXAMINED. — Fiji. MUSORSTOM 10: stn CP 17˚05’S, 178˚57’W, 550-687 m, 6 spms (paratypes MNHN 1330, 17˚10’S, 177˚56’E, 567-699 m, 1 lv (paratype MNHN 20445, Figs 3-4). 20442); stn CP 1341, 16˚53’S, 177˚44’E, 500-614 m, 6 spms, Tonga. BORDAU 2: stn CP 1556, 20˚11’S, 174˚45’W, 589- 1 lv, 2 rv (holotype MNHN 20441 and 7 paratypes MNHN 591 m, 2 spms, 1 lv (paratypes MNHN 20446); stn CP 1558, 20443, 1 HD). — BORDAU 1: stn CP 1409, 16˚02’S, 179˚30’W, 20˚10’S, 174˚43’W, 580-593 m, 5 spms (4 paratypes MNHN 557-558 m, 4 spms (paratypes MNHN 20444); stn CP 1420, 20447, 1 HD). 80 HENK H. DIJKSTRA & PHILIPPE MAESTRATI 1 2 3 5 6 4 7 9 10 8 DEEP-WATER PECTINOI D EA 81 DISTRIBUTION. — This species is so far only known from the easternmost regions of Melanesia, around Fiji and Tonga; live in 558-589 m. DESCRIPTION. — Shell up to c. 65 mm in height, rather solid, circular, inequivalve, somewhat inequilateral, umbonal angle c. 125˚, auricles short, small and equal in size, opaque to semi-translucent, left and right valve pale brownish, auricles of some specimens orange. Prodissoconch c. 250 µm in height. Left valve more convex than right, nearly smooth, bearing only delicate commarginal growth lines, more prominent and closely spaced near the ventral margin. Anterior and posterior auricles with close-set commarginal growth lines. Generally 12-14 interior ribs (on left valve slightly smaller than on right) and an auricular riblet on each side, commencing just below resilifer and extending to pallial line, with one or two intermediate rudimentary riblets. Right valve with fine and regularly, closely spaced commarginal lirae and granulate interstitial microsculpture (prismatic calcite layer). Marginal apron broken off of many specimens. Anterior and posterior auricles with close-set commarginal growth lines. Resilifer triangular. Dimensions of holotype: H 65.6, L 65.8, D 8.9 mm. REMARKS. — Propeamussium boucheti is morphologically closest to Propeamussium watsoni, but differs in size, external sculpture, internal ribbing and colour. The left valve of P. boucheti is almost smooth (with only commarginal growth lines), while that of P. watsoni is radially sculptured in the early growth stages and commarginally sculptured in later ontogeny. Propeamussium boucheti has more internal ribs (12-14, sometimes more, with interstitial rudimentary riblets) than P. watsoni (8-10, generally 10, without rudimentary riblets). Propeamussium boucheti is usually creamy or orange in colour, rarely whitish, whereas P. watsoni is whitish. Both species are semi-transparent, sometimes opaque. Propeamussium boucheti differs from P. alcocki in having a more solid shell (P. alcocki is very fragile). It also differs in shape, P. boucheti being almost circular, somewhat wider than high, whereas P. alcocki is higher than wide. Both species lack external sculpture and only have commarginal growth lines on the left valve.