Simone N. Brandão

First insights into the biodiversity and biogeography of the Southern Ocean deep sea

Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some taxa. The deeper parts of the Southern Ocean exhibit some unique environmental features, including a very deep continental shelf and a weakly stratified water column, and are the source for much of the deep water in the world ocean. These features suggest that deep-sea faunas around the Antarctic may be related both to adjacent shelf communities and to those in other oceans. Unlike shallow-water Antarctic benthic communities, however, little is known about life in this vast deep-sea region. Here, we report new data from recent sampling expeditions in the deep Weddell Sea and adjacent areas (748–6,348 m water depth) that reveal high levels of new biodiversity; for example, 674 isopods species, of which 585 were new to science. Bathymetric and biogeographic trends varied between taxa. In groups such as the isopods and polychaetes, slope assemblages included species that have invaded from the shelf. In other taxa, the shelf and slope assemblages were more distinct. Abyssal faunas tended to have stronger links to other oceans, particularly the Atlantic, but mainly in taxa with good dispersal capabilities, such as the Foraminifera. The isopods, ostracods and nematodes, which are poor dispersers, include many species currently known only from the Southern Ocean. Our findings challenge suggestions that deep-sea diversity is depressed in the Southern Ocean and provide a basis for exploring the evolutionary significance of the varied biogeographic patterns observed in this remote environment.

New species and occurrences of Bradleya Benson, 1972, Harleya Jellinek & Swanson, 2003 and Poseidonamicus Benson, 1972 (Ostracoda: Cytheroidea) from the Atlantic Sector of the Southern Ocean

The Southern Ocean shelf ostracod fauna is quite well known, while the bathyal and abyssal ones remain poorly understood. Herein, Recent Thaerocytheridae ostracods collected from deep regions in the Atlantic Sector of the Southern Ocean are described and figured. The discovery of Bradleya mesembrina Mazzini, 2005 extends its geographical and bathymetric distribution to the Antarctic zone of the Southern Ocean and to shallower (231 m) and to deeper regions (4420 m). Harleya ansoni (Whatley, Moguilevsky, Ramos & Coxill, 1998) is reported for the first time from the Weddell Sea. We also describe three new species: Poseidonamicus hunti Brandão & Päplow sp. nov., Poseidonamicus tainae Brandão sp. nov. and Poseidonamicus yasuharai Brandão & Päplow sp. nov. For the first time we provide SEM photos of the lectotype of Poseidonamicus viminea (Brady, 1880) nomen dubium. We observe that P. yasuharai displays features intermediate to Harleya and Poseidonamicus, indicating that these two genera may require new diagnoses. The bathymetric distribution of Poseidonamicus is extended to the abyssal zone and to shallower environments, and its geographical distribution is extended southwards. Finally, the inter-specific variability in the number and type of setae and claws found on several segments of Poseidonamicus limbs are intermediate between the highly variable Bairdioidea and the homogeneous Macrocyprididae.

Challenging deep-sea cosmopolitanism: taxonomic re-evaluation and biogeography of ‘Cythere dasyderma Brady, 1880’ (Ostracoda)

Cythere dasyderma Brady, 1880 was described from samples collected from all the world’s oceans during the HMS Challenger expedition in the 1870s. Subsequently, Cythere dasyderma (or Echinocythereis dasyderma, or Henryhowella dasyderma) has been recorded from the Late Eocene to Recent, from Atlantic, Arctic, Indian, Pacific and Southern oceans, and from intertidal to deep abyssal environments. However, even cursory inspection of illustrations from over 50 publications shows that several species have been included in ‘Cythere dasyderma’. Here, all syntypes of Cythere dasyderma Brady, 1880 archived in the Natural History Museum, London have been re-studied. This species is re-described, re-diagnosed and illustrated with scanning electron microscope images. Cythere dasyderma is assigned to Ayressoleberis gen. nov., which is described here. The geographical distribution of Ayressoleberis dasyderma (Brady, 1880) comb. nov. is no longer cosmopolitan, and includes only the type locality in the abyssal southeastern Pacific. Most of the specimens previously identified as Cythere dasyderma, or its synonyms, belong to other trachyleberidid genera (e.g. Henryhowella, Legitimocythere, Pennyella) and not to Ayressoleberis dasyderma comb. nov. A new species of Ayressoleberis, very similar to Ayressoleberis dasyderma comb. nov., is described and illustrated from specimens previously included amongst the syntypes of ‘Cythere acanthoderma Brady, 1880’. These latter specimens were collected from the continental slope of the southwestern Indian Ocean. This new species is left in open nomenclature herein because only two left valves are currently available. Supplementary Material: Previous records of Cythere dasyderma sensu lato, and, material included and excluded from the type series of Ayressoleberis dasyderma with corrected identifications are available at http://www.geolsoc.org.uk/SUP18572

The genus Polycope (Polycopidae, Ostracoda) in the North Atlantic and Arctic: taxonomy, distribution, and ecology

With almost 200 species described from all over the world, Polycope Sars, 1866 is the most specious and eurytopic genus of the exclusively marine family Polycopidae. Unlike other members of the subclass Myodocopa, polycopids are commonly found in fossiliferous rocks from strata as old as the Carboniferous, which makes them a useful tool in palaeoenvironmental reconstructions. The genus Polycope in particular is an opportunistic group and can putatively serve as an indicator of organic rich, fine grained sediment, reduced sea ice, and increased productivity, which is especially important when correlating biological data with the Quaternary climate changes that often requires accurate generic and species identifications. Polycopid taxonomy is relatively complicated because species tend to have conservative shell shapes and the soft body is extremely reduced, which can lead to numerous misidentifications, especially when fossil and Subrecent taxa are mixed and the shell is the only available source of taxonomic information. Here we study Polycope species collected during the first cruise of the IceAge project from the margin off Iceland. In total, four species have been recovered from 200 to 2747 m depth. They have been identified as P. pseudoinornata Chavtur, 1983, P. punctata Sars, 1869, P. yasuharai sp. nov., and P. sp. This is the first time since the middle of the 19th century that members of this genus have been studied in the North Atlantic and Arctic using both their soft parts and shells. It allowed us to reconsider numerous previous records of Polycope from this region. Beside a critical overview of the polycopid diversity in the North Atlantic and Arctic, and detailed taxonomic (re)descriptions of the newly collected specimens, we also provide maps of their distributions, analyse their ecological preferences, and offer a preliminary phylogeny of the North Atlantic species of Polycope based on 28S rDNA sequences. http://zoobank.org/urn:lsid:zoobank.org:pub:17EB9011-1715-4C1A-A854-FD0770F36E76

The ostracod genus Trachyleberis (Crustacea; Ostracoda) and its type species

The Trachyleberididae is one of the most diverse families of the Ostracoda in Mesozoic to present-day marine environments. Its type genus is Trachyleberis Brady, 1898, first described on the basis of specimens collected alive. Unfortunately the identity and morphological characteristics of the type species of Trachyleberis have long been the subject of confusion resulting from misidentifications and misunderstandings in the literature. We review the taxonomic history of this problem, providing extensive synonymies, new diagnoses, descriptions and illustrations of relevant species. We establish the identity of the type species of Trachyleberis, Cythere scabrocuneata Brady, 1880, by reference to a previously-designated lectotype from the Seto Inland Sea, Japan, noting that a second distinct species, Trachyleberis niitsumai Ishizaki, 1971, is represented in the original syntypic series. We consider that in the interests of nomenclatural and taxonomic stability C. scabrocuneata should be retained as the type species of Trachyleberis, despite the fact that the original description of the genus was based on a species misidentified as C. scabrocuneata and which was subsequently described as a new species, Trachyleberis lytteltonensis Harding and Sylvester-Bradley, 1953. The geographical and stratigraphical distributions of Trachyleberis are reconsidered in the light of our revision. Trachyleberis now comprises 18 known species inhabiting shallow marine environments of the Northwestern Pacific from Japan to the northern coast of the South China Sea off Hong Kong. The revised stratigraphic occurrence of Trachyleberis is from the Eocene to Recent. As many as 400 living and fossil species have been previously assigned to Trachyleberis and they range from the Cretaceous to the Recent; Cretaceous species formerly attributed to Trachyleberis are now re-assigned to other genera. We suggest that Trachyleberis most likely evolved from a Cythereis-like ancestor during the Eocene–Oligocene of Japan, the same area that is the centre of its modern distribution.

Species of Macrocyprina Triebel, 1960 (Crustacea, Ostracoda,Macrocyprididae) collected by the REVIZEE Program along Brazilian coast

Six samples collected from the eastern Brazilian continental shelf, along the states of Bahia and Espírito Santo, during the REVIZEE Program were analysed. Three species of Macrocyprina were encountered in these samples. Macrocyprina maddocksae sp. nov. is described. This species is diagnosed by the following combined characteristics: carapace fairly small, its lateral surface with three or four small subcircular patches, one small, subtriangular patch at anteroventral margin, one small, elongate, patch at posteroventral margin; male appendages V strongly asymmetrical, left appendage larger than right, podomere II of left appendage subtriangular, not recurved. Hemipenis subtrapezoidal. Furthermore, M. sp. nov. 3 Brandão, in press and M. sp. are recorded.

On the genus Thaumatoconcha Kornicker and Sohn (Halocyprida) with description of two new species from Southern Ocean deep sea

Two new Thaumatoconcha Kornicker and Sohn, 1976a species, T. dandani n. sp. and T. quasiporosa n. sp., have been described in the present paper. Both species have been collected during two expeditions to the Southern Ocean and are found in the deep sea. The first species is most closely related to T. caraionae Kornicker and Sohn, 1976a, but it has a very specific appearance of copulatory organ, anterior part being covered in small spines. The second species is most closely related to T. porosa Kornicker, 1985, and they differ in the carapace shape and morphology, while they have almost identical appearance of the male copulatory organ. A list of Thaumatocyprididae species and a key to the species of Thaumatoconcha are also presented in this paper.

New subgenus and new species of marine benthic ostracods of genus Doloria (Ostracoda; Myodocopina) from the Southern Ocean

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Septemoecia a new genus of halocyprid ostracod (Myodocopa, Halocyprididae, Bathyconchoeciinae) for the seven-spined species formerly attributed to Bathyconchoecia

The five species with seven large carapace spines that were previously assigned to the genus Bathyconchoecia are re-classified in a new genus Septemoecia. Septemoecia longispinata (Ellis, 1987) (new combination) is designated as the type species. The previously unknown adult female of S. georgei (Kornicker Rudjakov, 2004) (new combination) and adults of S. septemspinosa (Angel, 1970) (new combination) are described. Meristic and zoogeographical data are presented and a key to the species based on external carapace characters is provided.

Figure 1. Localities From The Andeep Stations, With X In New Subgenus And New Species Of Marine Benthic Ostracods Of Genus Doloria (Ostracoda; Myodocopina) From The Southern Ocean

FIGURE 1. Localities from the ANDEEP stations, with X + number indicating localities where Doloria was recorded and X (without number) indicating localities where Doloria was not recorded in the samples.