Abstract
Molecular systematic studies have indicated that the hexactinellid sponge species Rossella nodastrella Topsent (Lyssacinosida, Rossellidae), previously only known from the NE Atlantic, is only distantly related to its congeners, which are restricted to the Southern Ocean, representing the only case thus far reported of a diphyletic genus in the class Hexactinellida. Here we describe new material of "Rossella" nodastrella from cold-water coral reefs in the NW Atlantic (Florida). Morphological comparison with the holotype from the Azores and specimens recently reported from off Ireland reveal at least two distinct species, which we corroborate with molecular data. Because the diphyletic nature of "Rossella" is further supported with inclusion of the new specimens in the molecular phylogeny, we erect a new genus, Nodastrella gen. nov., for these two species. The Irish specimens are synonymized with our new species Nodastrella asconemaoida sp. nov. Subtle morphological and molecular differences between the E and W Atlantic specimens are for the time being ascribed to intraspecific geographic variation, but indicate that Nodastrella might contain more (sub) species, pending investigation of additional specimens, especially from intermediate locations.References
Boury-Esnault, N. & Rützler, K. (1997) Thesaurus of sponge morphology. Smithsonian Contributions to Zoology, 596, 1–55.
Cárdenas, P., Prez, T. & Boury-Esnault, N. 2012. Sponge systematics facing new challenges. Advances in Marine Biology, 61, 79–209.
Dohrmann, M., Collins, A.G. & Wörheide, G. (2009) New insights into the phylogeny of glass sponges (Porifera, Hexactinellida): monophyly of Lyssacinosida and Euplectellinae, and the phylogenetic position of Euretidae. Molecular Phylogenetics and Evolution, 52, 257–262.
Dohrmann, M., Gِcke, C., Janussen, D., Reitner, J., Lüter, C. & Wِörheide, G. (2011) Systematics and spicule evolution in dictyonal sponges (Hexactinellida: Sceptrulophora) with description of two new species. Zoological Journal of the Linnean Society, 163, 1003–1025.
Dohrmann, M., Haen, K.M., Lavrov, D.V. & Wِörheide, G. (2012) Molecular phylogeny of glass sponges (Porifera, Hexactinellida): increased taxon sampling and inclusion of the mitochondrial protein-coding gene, cytochrome oxidase subunit I. Hydrobiologia, 687, 11-20.
Dohrmann, M., Janussen, D., Reitner, J., Collins, A.G. & Wِörheide, G. (2008) Phylogeny and evolution of glass sponges (Porifera, Hexactinellida). Systematic Biology, 57, 388–405.
Erpenbeck, D., Hooper, J.N.A. & Wِörheide, G. (2006) CO1 phylogenies in diploblasts and the 'Barcoding of Life' — are we sequencing a suboptimal partition? Molecular Ecology Notes, 6, 550–553.
Felsenstein, J. (1985) Confidence limits on phylogenies: an approach using the bootstrap. Evolution, 39, 783–791.
Hillis, D.M. & Bull, J.J. (1993) An empirical test of bootstrapping as a method for assessing confidence in phylogenetic analysis. Systematic Biology, 42, 182–192.
Ijima, I. (1904) Studies on the Hexactinellida. Contribution IV (Rossellidae). Journal of the College of Science, Imperial University, Tokyo, Japan, 18, 1–124.
Janussen, D. & Reiswig, H.M. (2009) Hexactinellida (Porifera) from the ANDEEP III expedition to the Weddell Sea, Antarctica. Zootaxa, 2136, 1–20.
Lanave, C., Preparata, G., Saccone, C. & Serio, G. (1984) A new method for calculating evolutionary substitution rates. Journal of Molecular Evolution, 20, 86–93.
Padial, J.M., Miralles, A., De la Riva, I. & Vences, M. (2010) The integrative future of taxonomy. Frontiers in Zoology, 7, 16.
Pattengale, N.D., Alipour, M., Bininda-Emonds, O.R.P., Moret, B.M.E. & Stamatakis, A. (2010) How many bootstrap replicates are necessary? Journal of Computational Biology, 17, 337–354.
Savill, N.J., Hoyle, D.C. & Higgs, P.G. (2001) RNA sequence evolution with secondary structure constraints: comparison of substitution rate models using maximum-likelihood methods. Genetics, 157, 399–411.
Schlick-Steiner, B.C., Steiner, F.M., Seifert, B., Stauffer, C., Christian, E. & Crozier, R.H. (2010) Integrative taxonomy: a multisource approach to exploring biodiversity. Annual Review of Entomology, 55, 421–438.
Stamatakis, A. (2006a) RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed models. Bioinformatics, 22, 2688–2690.
Stamatakis, A. (2006b) Phylogenetic models of rate heterogeneity: a high performance computing perspective. In: Proceedings of the 20th IEEE/ACM International Parallel and Distributed Processing Symposium
Stamatakis, A., Hoover, P. & Rougemont, J. (2008) A rapid bootstrap algorithm for the RAxML web servers. Systematic Biology, 57, 758–771.
Tabachnick, K.R. (2002a) Family Rossellidae Schulze, 1885. In: Hooper, J.N.A. & van Soest, R.W.M. (Eds.), Systema Porifera. A Guide to the Classification of Sponges. Plenum, New York, pp. 1441–1505.
Tabachnick, K.R. (2002b) Family Euplectellidae Gray, 1867. In: Hooper, J.N.A. & van Soest, R.W.M. (Eds.), Systema Porifera. A Guide to the Classification of Sponges. Plenum, New York, pp. 1388–1434.
Tabachnick, K.R. & Collins, A.G. (2008) Glass sponges (Porifera, Hexactinellida) of the northern Mid-Atlantic Ridge. Marine Biology Research, 4, 25–47.
Tabachnick, K.R. & Menshenina, L.L. (2007) Revision of the genus Asconema (Porifera: Hexactinellida: Rossellidae). Journal of the Marine Biological Association of the United Kingdom, 87, 1403–1429.
Tabachnick, K.R. & Reiswig, H.M. (2002) Dictionary of Hexactinellida. In: Hooper, J.N.A. & van Soest, R.W.M. (Eds.), Systema Porifera. A Guide to the Classification of Sponges. Plenum, New York, pp. 1224–1229.
Topsent, E. (1915) Une Rossella des Açores (Rossella nodastrella n. sp.). Bulletin de l' Institut Océanographique, Monaco, 303, 1–6.
Topsent, E. (1928) Spongiaires de l’Atlantique et de la Méditerranée provenant des croisières du Prince Albert 1er de Monaco. Résultats des campagnes scientifiques accomplies par le Prince Albert I. Monaco, 74, 1–376.
van Soest, R.W.M. & Lavaleye, M.S.S. (2005) Diversity and abundance of sponges in bathyal coral reefs of Rockall Bank, NE Atlantic, from boxcore samples. Marine Biology Research, 1, 338–349.
van Soest, R.W.M., van Duyl, F.C., Maier, C., Lavaleye, M., Beglinger, E.J. & Tabachnick, K.R. (2007) Mass occurrence of Rossella nodastrella Topsent on bathyal coral reefs of Rockall Bank, W of Ireland (Lyssacinosida, Hexactinellida). In: Custódio, M.R., Lôbo-Hajdu, G., Hajdu, E. & Muricy, G. (Eds.), Porifera Research: Biodiversity, Innovation and Sustainability. Museu Nacional, Rio de Janeiro, pp. 645–652.
Wِörheide, G., Dohrmann, M., Erpenbeck, D., Larroux, C., Maldonado, M., Voigt, O., Borchiellini, C. & Lavrov, D.V. (2012) Deep phylogeny and evolution of sponges (Phylum Porifera). Advances in Marine Biology, 61, 1–78.
Yang, Z. (1994) Maximum likelihood phylogenetic estimation from DNA sequences with variable rates over sites: approximate methods. Journal of Molecular Evolution, 39, 306–314.