BIOGEOCAL

CEAMARC-AA

MD20 (SAFARI)

MD28 (SAFARI II)

Au cours de quatre campagnes océanographiques profondes, sept espèces de Sorberacea ont été récoltées. Trois espèces nouvelles sont décrites. Les Tuniciers carnivores ne sont plus une curiosité zoologique rare mais une classe représentée dans toutes les zones profondes des océans. L'augmentation du nombre de prélèvements a accru le nombre des espèces. La variabilité générique et spécifique révèle l'importance de cette direction évolutive des Tuniciers.

BENTHEDI, MD20 (SAFARI), MD28 (SAFARI II), ???msg.security.private???

Capistrum sorberae n. g., n. sp., is the first endoparasitic copepod found inside a tunicate belonging to the class Sorberacea (abyssal tunicates). This genus is characterized by the absence of setae and digestive tract, and by the presence of small male individuals located around the genital pores of the female.

BENTHEDI

Au cours de la campagne océanographique BENTHEDI dans le Nord-Est du canal du Mozambique, 25 espèces de Tuniciers profonds ont été récoltées, quatre sont nouvelles. Les spécimens sont tous de très petite taille. Les Stolidobranches et les Sorberacea dominent. On remarque une fois encore la rareté des Ascidies coloniales. La faune profonde dans cette région comprend de nombreuses espèces communes avec l'Atlantique.

BENTHEDI

MD20 (SAFARI), MD28 (SAFARI II)

Fifteen species, of which two are new, were collected in New Caledonia. The majority are also known from Australia and Indonesia. Only one species is considered as a component of the Southern temperate fauna. Ail the others have tropical affinities.

LAGON

Among the samples collected during MUSORSTOM 1 and 2 between 70 and 400 metres near the Philippines Islands, six species of ascidians were identified. One is a new species, and three others were unknown in this area.

MUSORSTOM 1, MUSORSTOM 2

Fimbrora calsubia genre et espèce nouveaux de la famille des Ascidiidae (Tunicata, Prochordata) a été récolté à une profondeur de 1865 m, à l'est de la Nouvelle-Calédonie par le submersible Cyana. Ces animaux, qui ont un siphon extrêmement développé, atteignent une taille de 30 cm. Ils ont dans leur manteau des vaisseaux sanguins muscularisés, caractère unique chez les tuniciers. Ils montrent des adaptations à un régime mixte microphage et macrophage, qui n'était connu que dans la famille des Octacnemidae. English : Fimbrora calsubia a new genus and species of the ascidian family Ascidiidae (Turnicata, Protochordata), has been collected from the deep water (1,865 m) easts of New Caledonica by the submersible Cyana. These animals, which have an extraordinary developed oral siphon, attain a lenght of 30 cm. They have muscular blood vessels in the body wall, which is unique among tunicates. They show adaptations for both microphagous and macrophagous feeding, a combination known until now only in the family Octacnemidae.

CALSUB

A survey of the bathyal and abyssal area around New Caledonia began in the South-West Pacific Ocean with some recent cruises of french research vessels. The ascidian fauna appears especially diverse, with 58 species of which 31 are new. The species described here belong to almost all genera known throughout the world showing deep-sea adaptations. The 5 main types of trophic adaptation defined for deep-sea tunicates are represented. Around New Caledonia the species having the most elaborate adaptations are more numerous than in the Antarctic, Atlantic or Indian Oceans. Some of the species may possibly be intermediates between shallow water and deep-sea genera. Some genera previously known by a small number of species are here very diverse, and provide the opportunity to discuss their affinities. This applies to the genera Pharyngodictyon (Aplousobranchia), Simla (Octacnemidae), Bathyoncus and Fungulus (Stolidobranchiata). A new interpretation of Corynascidia and Pterygascidia is proposed. With the discovery of 3 new species in New Caledonia, some evolutionary stages of the genus Molguloides (Molgulidae) may now be discussed in terms of branchial structure. A tabular key of the 13 species of this genus is presented. The bathymetric distribution is compared here and in other oceans. The species showing morphological adaptations to the deep-sea live at higher levels in the New Caledonia area than in other oceanic basins. However the presence of deep-sea forms in relatively high levels has been established in other tropical areas (Indonesia, Philippines, Comores). The higher temperature of the water at this depth in low latitudes may have less influence on the ascidian ecology than the seasonal variations occurring in temperate and cold areas at equivalent depths. The affinities of the New Caledonian deep-sea ascidians vary with the families and the kind of adaptations but they are most closely related to the antiboreal fauna of temperate and cold areas. There is no relationship with the shallow water fauna. For the Polyclinidae, with the greatest diversity, relations are established with New Zealand and the subantarctic areas. The deep-sea phlebobranchs are principally known from the southern hemisphere. New Caledonia has the largest number of Octacnemidae species wordwide. The Styelidae dominate in the deep Atlantic but are poorly represented here. The Pyuridae appear to have expanded from both Austral and Indomalayan areas. The majority of the deep-sea species of Molguloides live in the southern hemisphere and all the shallow-water species are Austral ; the genus is particularly diverse around New Caledonia.

BIOCAL, ???msg.security.private???, BIOGEOCAL, CHALCAL 2, LAGON, MUSORSTOM 4, MUSORSTOM 5, MUSORSTOM 6, SMIB 4

The deep marine bottoms around New Caledonia have been explored for forty years. The Kanacono (2016) and Kanadeep (2019) campaigns organized jointly by the Muséum national d’Histoire naturelle (MNHN) and the Institut de Recherche pour le Développement (IRD) are the complement of this investigation. They are a part of the program “La Planète Revisitée” in New Caledonia. Among the deep sea benthos twenty two ascidian species were collected and three represent new species showing the characteristic adaptations to an abyssal life. The high diversity of the tropical deep sea benthos is enhanced by these new results. No relations are found between littoral ascidians and forms living in the bathyal or abyssal areas.

KANACONO, KANADEEP

Impact of geochemical environment on metal bioaccumulation in deep-sea ascidians (Protochordates, Tunicates). The amount of Al, V, Mn, Ni and Cu in blood cells of the deep-sea ascidians genus Culeolus, performed by microanalysis, varies according to the geochemistry of the site and the taxonomic position. In Atlantic and Pacific ascidians inhabiting abyssal plains, the cells do not exhibit peculiar accumulations. They store Mn, Ni and Cu in the polymetallic nodule fields of Indian Ocean, Al in the East Pacific hydrothermal station. On the other hand, V storage should depend on individual or taxonomic peculiarities. In the absence of endocytosis, the Culeolus species constitute biological indicators of elements available in a dissolved state or incorporated in food.

BIOCAL, ???msg.security.private???, MD20 (SAFARI)

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Collectings by deep SCUBA dives have brought up 4 new species of Plurellidae, a family known by 2 Plurella species and one Microeastra. A new genus Plurascidia is also described, intermediate between the Plurellidae and the Ascidiidae families. All these new species are compared to the 3 Plurellidae already known and to a strange deep Ascidiidae, Fimbrora calsubia.

MUSORSTOM 6, MUSORSTOM 9

A large collection of 187 identified ascidian species is added to the records published in 1996 from the same tropical western Pacific islands. Most of the specimens were collected by the US Coral Reef Research Foundation (CRRF). They come from depths accessible by SCUBA diving. Most of the collection’s species are described and figured, their color in life is illustrated by 112 underwater photographs; among them 48 are new species representing a fourth of the material collected. This demonstrates how incomplete the knowledge of the ascidian diversity in this part of the world remains. Moreover, very small or inconspicuous species were seldom collected, as compared to the highly coloured and large forms. Many other immature specimens were also collected but their precise identification was not possible. Almost all littoral families are represented with the exception of the Molgulidae which are more characteristic of soft sediments, a biotope which was not investigated. Among the very diversified genera, the colonial forms largely dominate, including not only all the Aplousobranchia genera but also some Phlebobranchia and Stolidobranchia. Very often only one specimen was available, so a detailed biogeographical distribution cannot be given, and no island endemism can be defined

MUSORSTOM 3

The specimens collected during several recent oceanographic cruises in the tropical western Pacific, sponsored jointly by the MNHN and the IRD, consist of 53 ascidian species, and among them 16 new species. For others, the geographic distribution is increased in the western Pacific. The remarkably high diversity of these organisms between 50 and 1000 m in this part of the world is demonstrated. In all oceans at these depths the ascidian fauna is dominated by solitary organisms, whereas along the littoral fringe the majority of ascidian species are colonial. This systematic pattern is likely to be influenced by substrate: hard nearshore and soft offshore. In this study, among the new species, the solitary ascidians largely dominate, especially well represented by stolidobranchs with eight Styelidae of four genera, four Pyuridae with also four genera, and one Molgulidae. However the originality of this deep fauna is enhanced by the presence, in the typical Octacnemidae family, of a new genus Myopegma n. gen. with a very small species M. melanesium n. gen., n. sp. which has a very peculiar musculature justifying a new taxon.

BATHUS 2, BIOCAL, BORDAU 1, BORDAU 2, KARUBAR, LIFOU 2000, MUSORSTOM 10, MUSORSTOM 3, MUSORSTOM 8, MUSORSTOM 9, NORFOLK 1, SALOMON 1

A single, solitary, free living ascidian, Ascidia alisea sp. nov., collected from a sandy substrate on the Austral Ridge ( Polynesia) between 120 and 203 meters depth, is ovoid with a layer of sandy debris adhering to the tunic and has distinctive body muscles and neural area and an unusual course of its vas deferens.

BENTHAUS

LAGON, SMIB 1, SMIB 10, SMIB 2, SMIB 3, SMIB 4, SMIB 5, SMIB 6, SMIB 8, SMIB 9

Surveys of littoral invertebrates along the southern coast of Madagascar have produced the first study of ascidians in this part of the Indian Ocean. Collections were made by SCUBA divers in May and June 2010 down to 25m depth. This region is considered the southern limit for coral reefs but remains diverse biologically. Upwellings and an abundant plankton community particularly favour the abundance of ascidians in this area. Of the 39 species of non-didemnid species described here, eight are new. Ten species are common to South Africa. Other species were for the most part already known from the Mozambique Channel and a few have also been recorded in the western Pacific (either cosmopolitan or introduced).

ATIMO VATAE

CEAMARC-AA, REVOLTA III

In the Southern Hemisphere the species attributed to Corella eumyota, Traustedt, 1882 are likely more varied than previously expected. This ascidian species was described from specimens collected at Valparaiso (Chile). Until now it was considered as a widely distributed species in the southern hemisphere. New collections from Chile and the Antarctic area have allowed to separate two species and re-establish Corella antarctica Sluiter, 1905 as a valid species (Alurralde 2013).A morphological reexamination of many specimens from the MNHN collections and especially recent surveys as CEAMARC and REVOLTA confirms that Antarctic specimens from the Antarctic Peninsula and Terre Adélie obviously differ from sub-Antarctic material more varied than previously estimated. On the other hand, C. eumyota invasive in Europe (Lambert 2004) has been shown to be the same as specimens from Chile, New Zealand and other sub-Antarctic regions. The present morphological study compares Corella from different regions and describes a new species Corella brewinae n. sp that is found living mixed with C. eumyota populations.

CEAMARC-AA, MD42 - (SIBEX), REVOLTA II

Ascidians were collected along the shore of Iles du Salut and deeper on the slope in a program of evaluation of the biodiversity in Guiana. Most of the samples belong to already known species from the Caribbean area and Brazilian coast. The colonial forms dominate. The 6 new species have been dredged deeper than 50m but not found by SCUBA divers. In spite of an intensive sampling, the ascidian diversity in Guiana is low with 36 species recorded. This is the result of the abundance of sediment suspended in the water and uniformly deposited on all substrates which affects filtration rate and limits the settling of the ascidian larvae.

ILES DU SALUT

Four deep-sea ascidian species collected during the KAVIENG 2014 expedition in Papua New Guinea are described, including additional characteristics not reported previously. Fimbrora calsubia is classified within the family Ascidiidae, Dicopia fimbriata and Octacnemus bythius within Octacnemidae, and Culeolus recumbens within Pyuridae. Anatomical observations confirmed previous descriptions for these four species collected elsewhere. Here, we describe additional morphological features for these species and provide the first barcode DNA sequences (based on a fragment of the mitochondrial gene Cytochrome Oxidase I) for D. fimbriata and C. recumbens.

KAVIENG 2014

An inventory of the marine benthic fauna around Martinique was the aim of the European Madibenthos expedition 2016. Among a large number of invertebrates abundant ascidians were collected: the phlebobranchs and Styelidae among the stolidobranch were already studied and the results published (Monniot 2018a and b). A third group, belonging to the Pyuridae and Molgulidae (Stolidobranchia) is studied here; it includes 13 species, three of them recorded for the second time. Each of them is described and figured and the geographic distribution is given.

MADIBENTHOS

The aim of the Madibenthos 2016 expedition was to establish an inventory of the benthic marine fauna around Martinique. All kinds of biota were collected with different devices down to 40m depth. Among a large amount of invertebrates the ascidians were varied and abundant. Their study will be made in several steps. The first group studied concerns the Order Phlebobranchia represented here by species already described from the Caribbean area; one of them was collected for only the second time. The variability of internal characters which are ordinarily considered as generic or specific is discussed here for the genera Ascidia and Phallusia

MADIBENTHOS

An inventory of the marine benthic fauna around Martinique was the aim of the European Madibenthos expedition 2016. Among a large number of invertebrates abundant ascidians were collected: the phlebobranchs were already studied and the results published (Monniot 2018). A second group, belonging to the Styelidae (Stolidobranchia), includes 17 species of which one is new and new records for two other species. Each of them is described and the geographic distribution given.

MADIBENTHOS

Two species of bathyal ascidians were found for the first time in Indonesian waters : Fimbrora calsubia, Monniot & Monniot, 1991, previously known from New Caledonia and Styela squamosa Herdman, 1881, distributed on the continental slopes of the american pacific and circumantarctic areas. Culeolus herdmani Sluiter, 1904, originally described from Indonesian waters, was found again, at a depth of 230 m.

KARUBAR

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