Biodiversity of polychaetes with revision of Trichobranchidae and Antarctic Ampharetidae under consideration of cryptic speciation processes in the Southern Ocean
Atmospheric Science
Final Report Abstract
The project aimed to investigate the polychaete diversity and composition of the deep Weddell Sea and adjacent basin, contribute to a revision of the families Ampharetidae and Trichobranchidae, and gain first insights in species’ phylogeographic patterns and possible cryptic speciation in the deep sea. In its course the polychaete diversity in box-corer samples from the expedition ANDEEP-SYSTCO was analyzed and compared to former diversity studies in the area. As expected, polychaetes contributed a major part to the benthic invertebrate fauna. Diversity measures fell into the expected range known from the Antarctic deep sea with Shannon Indices of up to H’=3.3 and high evenness values. Also, patchiness of species with wide distribution and often low abundances was observed. As a special area the sea mount Maud Rise was investigated in greater detail showing a peculiar species composition. The polychaete fauna of Maud Rise was more similar to that of the Agulhas Basin than to Weddell Sea sites of similar depth. Surprisingly, tube-dwelling filter and suspension feeders found on Maud Rise were not found in the Weddell Sea samples of ANDEEP I-III, reasons for this clear difference in faunal composition were sought in the special current system of Maud Rise resulting in possibly very unique seasonality and quality in food input. Taxonomic investigations on the ampharetid and trichobranchid fauna of the Southern Ocean revealed a great number of unknown species. For Ampharetidae publication of the description of eight new species is currently in work. The most speciose genus was Anobothrus, for which three new species will be described. Also, a digital identification key for all Ampharetidae currently known for the Southern Ocean was created and awaits publication. Focus in the Trichobranchidae was on the genus Terebellides which before this study was only known with two species in the Southern Ocean. In course of this project twelve new species of Terebellides were discovered in the Southern Ocean deep sea, as well as further six new species in the western South Atlantic, descriptions are submitted, respectively in work, including a key to all species of Terebellides world-wide. For both genera, Anobothrus and Terebellides, molecular data were achieved from the Southern Ocean and the western South Atlantic. The molecular results agree with the morphological. In both genera species exhibit wide distribution ranges, however, a species overlap between the Southern Ocean and the western South Atlantic could not be observed. Whether this is due to small sample size or if a distribution barrier exists between the two basins has yet to be investigated. Apart from morphological and molecular investigations of the Ampharetidae and Trichobranchidae, four new species of Sphaerodoridae were described. In the Glyceridae, populations of a species originally identified as Glycera kerguelensis were investigated using the barcoding gene COI. Genetic distances between populations revealed three distinct clades which are proposed to be three different, cryptic species. Geographic distribution of clades is highly correlated to depth accounting for distribution barriers either through water masses or physiological restrains with bathymetric pressure. As part of a master study based on samples from the Southern Ocean the phylogeny of the order Opheliida was investigated. Former morphological and molecular studies on Opheliida revealed conversing results on the phylogenetic relationship of the subfamily Travisiinae to the Opheliidae and Scalibregmatidae. These studies, however, did not include Southern Ocean species, thus, the genera Ammotrypanella, Ophelina, Kesun, and Oligobregma, which are most abundant in the Southern Ocean, were underrepresented in these studies. In this study published data sets were combined with new data from the Southern Ocean species, resulting in three major suggestions: (1) Travisiinae should be treated as a separate family Travisidae, (2) Kesun should be treated as a synonym of Travisia, and (3) Ammotrypanella should be treated as a synonym of Ophelina. Also, hidden diversity could be found in the believed cosmopolitan species Axiokebuita millsi and Scalibregma inflatum.
Publications
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(2009). Bathymetric distribution of Southern Ocean macrofaunal taxa: Bivalvia, Gastropoda, Isopoda, and Polychaeta. Deep-Sea Research Part I 56. 2013-2025
Brandt, A., Linse, K., & Schüller, M.
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(2009). Community structure and diversity of polychaetes (Annelida) in the deep Weddell Sea (Southern Ocean) and adjacent basins. Marine Biodiversity 39(2). 95-108
Schüller, M., Ebbe, B. & Wägele, J.W
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(2010). New insights in the taxonomy of Trichobranchidae (Polychaeta) with description of a new Terebellides species. Zootaxa 2395. 1-16
Schüller, M. & Hutchings, P.A.
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(2011). Diet insights of deep-sea polychaetes derived from fatty acid analyses 58(1-2). 153-162. Deep-Sea Research II
Würzberg, L., Brandt, A., Peters, J. & Schüller, M.
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(2011). Diversity and distribution of Polychaeta in deep Antarctic and Subantarctic waters along the Greenwich meridian. Deep-Sea Research II 58. 2004-2012
Wilmsen, E. & Schüller, M.
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(2011). Evidence for a role of bathymetry and emergence in speciation in the genus Glycera (Glyceridae, Polychaeta) from the deep Eastern Weddell Sea. Polar Biology 34(4). 549-564
Schüller, M.
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(2011). Maud Rise – A snapshot through the water column. Deep-Sea Research II 58. 1962-1982
Brandt, A., Bathmann, U., Brix, S., Cisewski, B., Flores, H., Göcke, C., Janussen, D., Krägefsky, S., Kruse, S., Leach, H., Linse, K., Pakhomov, E., Peeken, I., Riehl, T., Sauter, E., Sachs, O., Schüller, M., Schroedl, M., Schwabe, E., Strass, V., van Franeker, J., Wilmsen, E.
