MUSORSTOM 1

60 Ophiurid species, mainly bathyal, were sampled by MUSORSTOM Expedition in the area of Manila (Philippine Islands) 4 species are new for Science: Astrotoma drachi, Ophioplinthaca manillae, Ophiurothamnus musorstomae, Ophiotreta speciosa. 13 species are refound for the first time since their original diagnosis. A new combination is established, Ophiodaphne formata, because Ophiodaphne materna Koehler (1930) appears to be the juvenile form of “Amphioplus” formatus (Koehler, 1905). Two other species are synonymized: Ophiomoeris pentagona Murakami (1944) with Ophiogyptis nodosa Koehler (1905) and Ophiothrix cumulata Koehler (1922) with Ophiothrix crassispina Koehler (1905). Amphiacantha transacta Koehler (1930) is transferred into fhe genus Amphilimna Verrill.

MUSORSTOM 1

Two new alkaloids, phloeodictine A (1) and phloeodictine B (21, possessing an unprecedented 6-hydroxy- 1,2,3,4 tetrahydropyrrolo[ 1,2-a]pyrimidinium skeleton have been isolated from an undescribed species of the deep sponge Phbeodictyon. The structures were determined by extensive spectroscopic analysis particularly two-dimensional NMR experiments. Both compounds exhibited in vitzo antibacterial activity against Gram-positive and Gram-negative bacteria and were moderately cytotoxic against KB cells.

SMIB 3

Soft sedimentary ocean floors are inhospitable for sponges except for a few species which provide their own anchors in the form of rods that act as stakes. Of these, the Monorhaphis (Porifera hexactinellida) is remarkable for the size of its single anchoring spicule. It is also quite rare. After the first reported finding by Chun [1] on his 1898-99 Indian Ocean expedition, the only other report would appear to be that by Burton [2] in 1959.

BIOCAL

During the CALSUB cruise, bathyal environments were explored off the New Caledonia corallian platfdrms (southwestern Pacific). Green algae were observed down to a depth of 1 IO m, and red algae down to 145 m. Algal blocks, pebbles and sands contribute to sedimentation to a depth of 400 m and beyond, and are mixed with autochthonous fossils and bioclasts produced by bathyal benthos. Epibathyal fauna suggests similarities with Jurassic and Cretaceous fauna of Tethyan margins (Nautilus, pleurotomarian gastropods, sponges, brachiopods and crinoids…). Richness and abundance of the benthos are the highest in areas where currents are frequent between 300 m and 700 m (sometimes 10 to 20 terebratulid brachiopods per m2 or dense populations of echinoderms entirely covering the substrate). Such currents induce erosion of' substrate or bioclastic accumulations. Biocorrosion seems to be very active in erosion processes, especially on hard grounds. Burrows and traces show the importance of sediment bioturbation on slopes. The occurrence on bathyal slope of some taphonomic processes previously known from geological series and generally considered as closely related lo shallow-water environments should be emphasized.

CALSUB

L'exploration de la faune profonde de NouvelleCalédonie a débuté par des campagnes d'essai de 1977 à 1979 sur des fonds de 200 m à 1000 m au large de la Grande Terre, de l'île des Pins et des îles Loyauté (Intès, 1978). A partir de 1985, elle s'est élargie et intensifiée avec les campagnes MUSORSTOM 4 à 6 et CHALCAL (Richer de Forges, 1990), BIOCAL, BIOGEOCAL et SMIB, complétées par des observations directes à l'aide de la soucoupe plongeante Cyana lors de la campagne CALSUB. Nous ne donnerons ici que les grands traits de l'étagement de la macrofaune et de la mégafaune benthique en insistant sur les observations directes insitu lors de la campagne CALSUB et sur la liaison avec les caractères du milieu.

CALSUB

T w e n t y species of the family of Ophiuridae, belonging to twelve different genera, were collected along the submarine slopes of the Reunion Island, between 2 0 and more 4 0 0 0 m depths. A m o n g t h e m , Ophiophyllum borbonica is n e w f o r S c i e n c e ; Ophiomastus platydiscus H . L . Clark a n d Uriopha ios P a t e r s o n , r e s p e c t i v e l y k n o w n f r o m Z a n z i b a r area a n d Cape V e r d e Islands, are r e f o u n d for t h e first t i m e since their o r i g i n a l d i a g n o s i s . T h e g e n u s Ophiophyllum, p r e v i o u s l y belonging to the subfamily Ophiolepidinae, is placed in the subfamily Ophiurinae.

MD32 (REUNION)