Additional records of bathyal ascidians (Tunicata) from the New Caledonia region.

Two expeditions EXBODI (2011) and SPANBIOS (2021) sampled the invertebrate fauna of deep bottoms on each side of New Caledonia. Many ascidians were collected and the most part are already known species. Among the 13 species described and figured, two are new to science. All have typical characters of a deep habitat. Variability of the internal anatomy is described for abundant specimens of the same species from the same location. There is no concordance with the littoral ascidian fauna.

New records of deep-sea ascidians (Tunicata, Ascidiacea) from the New Caledonia region.

The deep marine bottoms around New Caledonia have been explored for forty years. The Kanacono (2016) and Kanadeep (2019) campaigns organized jointly by the Musum national dHistoire naturelle (MNHN) and the Institut de Recherche pour le Dveloppement (IRD) are the complement of this investigation. They are a part of the program La Plante Revisite 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.

Questions on the taxonomic status of species of Protoholozoa Kott 1969 (Ascidiacea, Aplousobranchia, Holozoidae) with a description of a new genus.

Among numerous ascidians, two colonies of the deep species Protoholozoa pedunculata Kott, 1969 were collected in 2017 by the French Poker 4 survey, Indian Ocean. The larvae of this species are described here for the first time. The present material shows the disposition of adhesive papillae in a line and incubation in the atrial cavity. That is different from what was first reported and from what is known in other species of the genus, which show triradiate adhesive papillae and incubation in a brood pouch. This new data leads us to discuss the taxonomic status of different species, leaving Protoholozoa Kott, 1969 for the previous ones and creating Scotiazoa gen. nov. for species with triradiate larval papillae and brood pouch.

Ascidians collected during the Madibenthos expedition in Martinique 3. Stolidobranchia, Pyuridae and Molgulidae.

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.

Ascidians collected during the Madibenthos expedition in Martinique: 2. Stolidobranchia, Styelidae.

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.

Ascidians collected during the Madibenthos expedition in Martinique: 1-Phlebobranchia.

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.

Microcosmus anchylodeirus (Ascidiacea, Pyuridae) introduced in the Mediterranean Sea.

Several specimens of Microcosmus anchylodeirus Traustedt, 1883 were successively collected by dives along the shore of southern Corsica. With a corrugated tunic covered with all kinds of epibionts they are difficult to notice on the rocks and are recorded for the first time from Mediterranean Sea. These ascidians correspond well internally and externally to Atlantic specimens from the Caribbean islands and also to those described from Brazil. Pacific specimens identified as Microcosmus multitentaculatus Tokioka, 1953 from Japan and Korea have been examined and are now considered as junior synonyms of Microcosmus anchylodeirus, a species whose origin is not known.

Ascidians (Tunicata) of the French Guiana Expedition.

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.

A new species of Polyandrocarpa (Ascidiacea, Styelidae) in the Mediterranean Sea.

Polyandrocarpa arianae n. sp. was collected repeatedly by trawls deeper than 90m from several parts of the Mediterranean Sea. It is described and compared to the shallow species Polyandrocarpa zorritensis (Van Name, 1931) considered as invasive in the Mediterranean Sea. Among the colonial Styelidae the other species which belong to the same genus differ by the colony and zooid shape, the presence/absence of endocarps and of a caecum in the gut loop and by the location and structure of the polycarps.

Pedunculate Molgula species (Ascidiidae, Molgulidae) from the French Antarctic sector. Redescription and taxonomic revision.

Following the Challenger Expedition in the southern Hemisphere, several international surveys have studied Antarctic ascidians. Several pedunculate Molgula were successively described under various names. From the French part of the Antarctic continent and the Kerguelen area, numerous Molgula were recently collected. They are described here in different species, but closely allied. Their taxonomy is revised with an historical review of the most detailed publications and a link to the ancient names.

Redescription of Herdmania papietensis Herdman, 1882 (Ascidiacea, Pyuridae) from Polynesia.

Among the Pyuridae family the genus Herdmania Lahille, 1888 differs from the diagnose of Pyura Molina, 1782 by the presence of needle-shape echinated spicules in all tissues. These striking elements formerly led to identify many specimens collected in tropical or temperate waters as Herdmania momus (Savigny, 1916). Later the genus was split into several species with a special attention to the different structure of the gonoducts. Newly collected specimens and a revision of previously described animals in Polynesia lead to the redescription of Herdmania papietensis Herdman 1882 from Polynesia and to compare it to the other Herdmania species known in the Pacific Ocean. 

The ascidian-associated mysid Corellamysis eltanina gen.nov., sp.nov. (Mysida, Mysidae, Heteromysinae): a new symbiotic relationship from the Southern Ocean.

A new mysid species representing a new genus is described based on specimens collected in the 1968 cruise of the U.S. Navy Ship Eltanin from the Macquarie Island region (Southern Ocean). The new mysid, Corellamysis eltanina, is characterized by the globular eyes lacking definite eyestalks, the seven and eighth thoracic endopods specialized as gnathopods forming a strong subchela, and by the armature and shape of the uropod endopod and telson. Corellamysis eltanina lives only in the branchial sacs of the ascidian Corella brewinae suggesting an obligate endocommensal symbiotic association. Therefore, this is the first known report of a mysid living symbiotically with a benthic tunicate, as well as the first report of a mysid symbiosis from the Southern Ocean. The distribution and habitats of known symbiont mysids are reviewed. An update of identification key to world genera and subgenera of Heteromysinae is suggested. 

The genus Corella (Ascidiacea, Phlebobranchia, Corellidae) in the Southern Hemisphere with description of a new species.

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 re-examination 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.

Ascidia subterranea sp. nov. (Phlebobranchia: Ascidiidae), a new tunicate belonging to the A. sydneiensis Stimpson, 1855 group, found as burrow associate of Axiopsis serratifrons A. Milne-Edwards, 1873 (Decapoda: Axiidae) on Derawan Island, Indonesia.

A new tunicate, Ascidia subterranea sp. nov., was found in burrows of the axiid crustacean Axiopsis serratifrons on Derawan Island, Indonesia. It differs from other ascidians in its habitat as well as numerous morphological peculiarities which are described in detail. The shrimp Rostronia stylirostris Holthuis, 1952 was found inside A. subterranea sp. nov., and 4 species of bivalves, 3 species of polychaetes, 1 gastropod, 1 polyplacophoran and 1 sponge species were found as burrow associates besides the ascidian.