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FIG. 3 in Alleged cosmopolitanism in sponges: the example of a common Arctic Polymastia (Porifera, Demospongiae, Hadromerida)
No full textFIG. 3. — Polymastia arctica (Merejkowsky, 1878), spicules. Abbreviations: is, intermediate subtylostyles; ps, principal subtylostyles; t, small palisade tylostyles. Scale bar: 100 µm.Published as part of Plotkin, Alexander & Boury-Esnault, Nicole, 2004, Alleged cosmopolitanism in sponges: the example of a common Arctic Polymastia (Porifera, Demospongiae, Hadromerida), pp. 13-20 in Zoosystema 26 (1) on page 18, DOI: 10.5281/zenodo.539369
Vosmaeria Fristedt, 1885 (Porifera, Demospongiae, Halichondriidae): revision of species, phylogenetic reconstruction and evidence for split
No full textAll species of Vosmaeria are re- described using type and additional material. The phylogenetic relationships between Vosmaeria ssp. and other demosponge taxa are reconstructed based on 28S- rDNA sequences analyses. V. crustacea, the type species, is widely distributed in the NE Atlantic and characterized by a thinly encrusting growth form, the location of ostia and oscula exclusively on papillae, a dense and firm ectosomal skeleton, the absence of subectosomal aquiferous cavities and the blunt distal tips of tylostyles. Hydrochemical conditions may account for the smaller spicule size of the White Sea population compared to those in the North and Barents Sea. V. reticulosa, known from the Chilean and Peruvian coasts, is distinguished by a massive growth form, a reticulated ectosomal skeleton, the absence of papillae, the scattering of ostia and oscula over the surface, the presence of subectosomal cavities and the acerate distal tips of tylostyles. V. levigata, known exclusively from the English Channel, shares the absence of papillae and the acerate distal tips of tylostyles with V. reticulosa, but the only surviving material consists of dissociated spicules slides, and consequently its status remains unclear. On the basis of substantial morphological differences we propose to split Vosmaeria into two monospecific genera - Vosmaeria, with type species V. crustacea, and Johannesia gen. nov., with type species V. reticulosa. Both genera clearly belong to Halichondriidae based on the tangential arrangement of the ectosomal skeleton, the presence of oxeas. Molecular phylogenetic analyses support a split into two genera and confirm the classification of both within the Halichondriidae
Vosmaeria Fristedt, 1885 (Porifera, Demospongiae, Halichondriidae): revision of species, phylogenetic reconstruction and evidence for split
No full textAll species of Vosmaeria are re- described using type and additional material. The phylogenetic relationships between Vosmaeria ssp. and other demosponge taxa are reconstructed based on 28S- rDNA sequences analyses. V. crustacea, the type species, is widely distributed in the NE Atlantic and characterized by a thinly encrusting growth form, the location of ostia and oscula exclusively on papillae, a dense and firm ectosomal skeleton, the absence of subectosomal aquiferous cavities and the blunt distal tips of tylostyles. Hydrochemical conditions may account for the smaller spicule size of the White Sea population compared to those in the North and Barents Sea. V. reticulosa, known from the Chilean and Peruvian coasts, is distinguished by a massive growth form, a reticulated ectosomal skeleton, the absence of papillae, the scattering of ostia and oscula over the surface, the presence of subectosomal cavities and the acerate distal tips of tylostyles. V. levigata, known exclusively from the English Channel, shares the absence of papillae and the acerate distal tips of tylostyles with V. reticulosa, but the only surviving material consists of dissociated spicules slides, and consequently its status remains unclear. On the basis of substantial morphological differences we propose to split Vosmaeria into two monospecific genera - Vosmaeria, with type species V. crustacea, and Johannesia gen. nov., with type species V. reticulosa. Both genera clearly belong to Halichondriidae based on the tangential arrangement of the ectosomal skeleton, the presence of oxeas. Molecular phylogenetic analyses support a split into two genera and confirm the classification of both within the Halichondriidae
FIGURE 6. Polymastia zitteli. A–specimen SMF 10557. B in Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *
No full textFIGURE 6. Polymastia zitteli. A–specimen SMF 10557. B–histological section of idem, general view. C, D–the same as B, details of cortex. E–surface view of detached cortex of idem. F–principal and intermediary spicules. G–small spicules. Scale bars: A 10 mm; B 1 mm; C–E 0.2 mm; F–G 0.1 mm.Published as part of Plotkin, Alexander S. & Janussen, Dorte, 2008, Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *, pp. 95-135 in Zootaxa 1866 on page 110, DOI: 10.5281/zenodo.18387
FIGURE 3. Astrotylus astrotylus. A—holotype SMF 10518 in Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *
No full textFIGURE 3. Astrotylus astrotylus. A—holotype SMF 10518, an arrow indicates a papilla. B—histological section of idem. C—principal tylostyle, general view. D—proximal end of idem. E—small tylostyle. F—astrotylostyles, general view. G—detail of fungiform serrated tyle. Scale bars: A 5 mm; B 1 mm; C–E 0.1 mm; F 0.01 mm; G 0.001 mm.Published as part of Plotkin, Alexander S. & Janussen, Dorte, 2008, Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *, pp. 95-135 in Zootaxa 1866 on page 101, DOI: 10.5281/zenodo.18387
FIGURE 4 in Vosmaeria Fristedt, 1885 (Porifera, Demospongiae, Halichondriidae): revision of species, phylogenetic reconstruction and evidence for split
No full textFIGURE 4. Vosmaeria crustacea: (sub)tylostyles at SEM. Scale bar for A: 0.1 mm, scale bars for B–G: 0.01 mm. A– general view. B–considerably displaced tyle. C–moderately displaced tyle. D–slightly displaced tyle. E–weakly developed tyle. F–terminally located tyle. G–distal tip.Published as part of Gerasimova, Elena, Erpenbeck, Dirk & Plotkin, Alexander, 2008, Vosmaeria Fristedt, 1885 (Porifera, Demospongiae, Halichondriidae): revision of species, phylogenetic reconstruction and evidence for split, pp. 1-37 in Zootaxa 1694 on page 11, DOI: 10.5281/zenodo.18067
Radiella Schmidt 1870
No full textGenus Radiella Schmidt, 1870 Diagnosis (emended from BouryEsnault 2002): Sponges are circular, lenticular or hemispherical. The inhalant and exhalant apertures are grouped on papillae. The choanosomal skeleton is composed of diverging tracts of principal spicules emanating from a central nucleus at the sponge base and by groups of fusiform tylostyles. The skeleton of the lower surface is constituted by an envelope of principal subtylostyles or styles covered by a thin palisade of cortical tylostyles. The upper surface is composed of one or two layers of tylostyles. A fringe of additional spicules is observed at the border between the upper and the lower surface. Emendation: The presence of a marginal fringe is added. Type species: Radiella sol Schmidt, 1870 (by subsequent designation).Published as part of Plotkin, Alexander S. & Janussen, Dorte, 2008, Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *, pp. 95-135 in Zootaxa 1866 on page 111, DOI: 10.5281/zenodo.18387
Polymastia Bowerbank 1864
No full textGenus Polymastia Bowerbank, 1864 Polymastia Bowerbank, 1864: 177. Penicillaria Gray, 1867: 527. Rinalda Schmidt, 1870: 51. TYPE SPECIES. — Spongia mamillaris Müller, 1806: 44 (by monotypy). DIAGNOSIS (from Boury-Esnault 2002). — Polymastiidae, thickly encrusting, spherical or cushionshaped, always with papillae. Choanosomal skeleton composed of radial tracts of principal spicules between which free spicules are scattered. Ectosomal skeleton composed of at least two layers, the superficial one is a palisade of small tylostyles, the lower layer is made of intermediary spicules, tangential to the surface. The principal spicules can be tylostyles, subtylostyles, styles or strongyloxeas, intermediary spicules are most often tylostyles, and ectosomal spicules are always tylostyles.Published as part of Plotkin, Alexander & Boury-Esnault, Nicole, 2004, Alleged cosmopolitanism in sponges: the example of a common Arctic Polymastia (Porifera, Demospongiae, Hadromerida), pp. 13-20 in Zoosystema 26 (1) on page 15, DOI: 10.5281/zenodo.539369
Suberitidae
No full textFamily Suberitidae Diagnosis (sensu van Soest 2002): Sponges are globular, ramose, stipitate, massive or encrusting. Megascleres are usually tylostyles, occasionally styles, strongyloxeas or centrotylote oxeas. Microscleres are usually absent, when present confined to microrhabds and trichodragmas. In cross section, megascleres are usually arranged in bouquets at the surface, in more massive species becoming progressively confusedly arranged towards the interior, but overall structure may also be strictly radial or show a strong axial orientation. In one genus the spicules at the surface are arranged tangentially. There is no recognizable cortex. In thinly encrusting species spicule orientation is either parallel or perpendicular to the substratum. Modifications of shape and position of the tylostyle heads are common; they can be lobate, pearshaped, dropshaped or subterminal.Published as part of Plotkin, Alexander S. & Janussen, Dorte, 2008, Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *, pp. 95-135 in Zootaxa 1866 on page 123, DOI: 10.5281/zenodo.18387
Rhizaxinella Keller 1880
No full textGenus Rhizaxinella Keller, 1880 Diagnosis (sensu van Soest 2002): Pedunculate sponges, with spherical, ovoid or cylindrical body carried on a simple or ramified stalk, normally attached to the substrate by a root system; usually an apical oscule. Body with a moreorless radial skeleton and with brushes of spicules at the surface, skeleton of the stalk a tightly packed mass of aligned megascleres, bound by spongin. Megascleres are tylostyles of different sizes with raphides in trichodragmas. Type species: Rhizaxinella clavigera Keller, 1880 (by monotypy) = junior synonym of Alcyonium pyrifera delle Chiaje, 1828.Published as part of Plotkin, Alexander S. & Janussen, Dorte, 2008, Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *, pp. 95-135 in Zootaxa 1866 on page 126, DOI: 10.5281/zenodo.18387
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