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In this study, we describe a new species of cladorhizid sponge, which shows a very peculiar mode of life: It always occurs in association with the scleractinian cold-water corals Lophelia pertusa and Madrepora oculata. Although the sponge lives in nutrient-rich areas, we document its carnivorous feeding behavior. The identity of the new species was verified using molecular markers: the species is very closely related to the North-Atlantic Cladorhiza abyssicola, but it differs distinctly, and forms a monophyletic clade. The two species might be considered very close relatives, probably sister species deriving from a common ancestor.

Vargas, S., Erpenbeck, D., Gocke, C., Hall, K. A., Hooper, J. N. A., Janussen, D. & Worheide, G. (2012) Molecular phylogeny of Abyssocladia (Cladorhizidae: Poecilosclerida) and Phelloderma (Phellodermidae: Poecilosclerida) suggests a diversification of chelae microscleres in cladorhizid sponges. Zoologica Scripta, 42, 106116. The taxonomic placement of Abyssocladia Levi, 1964 (Poecilosclerida) is controversial, having been assigned at various times to three different families (Mycalidae, Cladorhizidae and Phellodermidae) in two different suborders (Mycalina and Myxillina, respectively), since its inception in 1964. It shares the general body plan with the carnivorous sponge family Cladorhizidae (Mycalina), including the lack of an aquiferous system. Nevertheless, it also has chela spicules apparently identical to those in PhellodermaRidley & Dendy 1886 (Phellodermidae, Myxillina). The ongoing debate on the position of Abyssocladia ultimately reduces to a discussion on the use of chelae morphology to infer phylogenetic relationships within Poecilosclerida. Here, we infer the phylogenetic relationships of the genera Phelloderma and Abyssocladia using two independent molecular markers (28S rDNA and COI), showing that Abyssocladia is not closely related to Phelloderma and belongs in Cladorhizidae. We suggest that despite their complexity, chelae morphology can evolve independently in different poecilosclerid lineages and as such might be potentially misleading as indicator of the phylogenetic history of the group. We also provide the first phylogenetic analysis of the carnivorous sponge family Cladorhizidae and give first insights into the evolution of this feeding mode in Poecilosclerida and, more generally, in Porifera.

In this paper we report on recently collected specimens of glass sponges belonging to Farreidae Gray, 1872, and Tretodictyidae Schulze, 1886 (Porifera: Hexactinellida: Hexactinosida). All specimens represent new geographical records for their genera: Coral Sea for Aspidoscopulia Reiswig, 2002 (Farreidae) and Psilocalyx Ijima, 1927 (Tretodictyidae); north-west Atlantic for Sarostegia Topsent, 1904 (Farreidae). Two new species, Aspidoscopulia australia Dohrmann, Gocke & Janussen sp. nov. and Aspidoscopulia ospreya Dohrmann, Gocke & Janussen sp. nov., are described. To investigate further the evolution of hexactinosidan sponges, we sequenced two nuclear (18S and 28S rDNA) and two mitochondrial [16S ribosomal rDNA, cytochrome oxidase subunit I (COI)] genes from these specimens, as well as from a recently described new species of Lonchiphora Ijima, 1927 (Farreidae). Besides corroborating the monophyly of Tretodictyidae, our molecular phylogenetic analyses support a clade of clavule-bearing sponges with a farreoid dictyonal framework (i.e. Farreidae sensu stricto). In contrast, Sarostegia, which lacks these features, appears unrelated to this clade – instead our data are consistent with an earlier placement of this genus in Euretidae Zittel, 1877. We introduce formally the taxon Sceptrulophora Mehl 1992, and emend the classification of Hexactinosida to reflect this move and our new findings regarding the position of Sarostegia. Finally, we discuss implications of the molecular phylogeny for the evolution of sceptrules, the defining autapomorphy of Sceptrulophora. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, 1003–1025.

The Drake Passage has over 20 seamounts and ridges but it is notorious for large waves, fierce storms and strong currents that make benthic sampling difficult and therefore infrequent. Seamounts often have diverse sponge communities and may have high levels of endemism. Hexactinellida from Sars Seamount, an area in which the sponges had not previously been studied, and the Shackleton fracture zone were collected on a research cruise by the Nathaniel B Palmer in the Drake Passage, Southern Ocean. In total, from all cruise stations, 103 specimens of Hexactinellida were collected, however many appeared to be fragments of dead specimens and could not be identified due to missing microscleres. From Sars Seamount 127 sponge specimens were taken and from the Shackleton Fracture Zone 76 sponge specimens were taken; of these 36 and 16 respectively were Hexactinellida. From these two areas three new species of Hexactinellida are described: Doconesthes robinsoni sp. nov., Sympagella walleri sp. nov. and Caulophacus palmeri sp. nov and new records were made of Aulocalyx irregularis and Rossella antarctica .

In this study we provide evidence that the species Rossella podagrosa Kirkpatrick, 1907, commonly considered a synonym of Rossella racovitzae Topsent, 1901, is truly a valid species. We show that it can be clearly distinguished from other species especially when taking into consideration the in situ habitus of the sponge in combination with the spicules. Furthermore we demonstrate the weaknesses in the so far published synonymy concept for the very complicated genus Rossella Carter, 1872. From this we conclude that the best strategy for further analysis of Rossella and establishment of acceptable synonymies will need to be based on detailed examination of the spicules, the holotypes, and in situ habitus. When possible it will be useful to analyze specimens from all Antarctic oceanographic regions.

The paper reports on two new species of calcareous sponges (Porifera, Calcarea) from the Antarctic Weddell Sea, Clathrina brandtae sp. nov. and Leucetta delicata sp. nov., collected at 600 m depth during the ANT XXIV/2-SYSTCO expedition in January 2008. The new species are described based on a combination of morphological and molecular data. With these new additions the number of species of calcareous sponges reported from south of 50°S (~south of the Polar Front) reaches 50 species. We report an exceptionally high degree of endemism within the group, and as many as 44 out of the 50 species of calcareous sponges are solely confined to Antarctic waters. An updated list of species of calcareous sponges from the area is provided.

In this study, we present the demosponges sampled in the Antarctic Weddell Sea during the ANT-XXIV/2 (SYSTCO I) expedition (28.11.2007–04.02.2008) by the RV Polarstern. This collection comprises 43 species of Demospongiae of which four species are new to science, three of which are described herein, Cornulum antarcticum sp. nov., Cladorhiza penniformis sp. nov., and Desmacella koltuni sp. nov. We furthermore provide short descriptions and remarks for all species found, and in cases of rare or badly characterized species we also provide detailed documentation and descriptions of our material. In conclusion, we discuss the comparative faunistic and ecological aspects of our collection with respect to the Weddell Sea sponge fauna.

The genus Rossella Carter, 1872 comprises a group of very abundant and large sponges, which often dominate and even define the benthic habitats of the Antarctic shelf. While the ecological role and importance of the genus is unquestionable, the taxonomy of Rossella has been in a state of flux since its erection in 1872. Several species have been described, many of which have proven to be individual representatives of species with high variation in diagnostic characters, thus many published species are actually synonyms and a valid concept is still lacking. Here, we present the Rossella -fauna of one station sampled during the SYSTCO-I expedition in winter 2007/08 at 600 m depth on the lower Ekstrom-shelf near Kapp Norvegia, Eastern Weddell Sea, Antarctica. This sponge fauna showed some remarkable peculiarities in its characters, especially an unusually large growth of many microscleres, which will broaden the diagnoses of many Rossella spp. significantly. Implications for the definitions of these species are discussed.

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.