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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
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
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
FIGURE 14 in Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *
No full textFIGURE 14. Aaptos robustus sp. nov. A—holotype SMF 10562, upper surface. B—the same as A, basal surface after detaching from substrate. C—histological section of idem, general view. D—the same as C, detail of cortex with perpendicular and tangentially lying tylostyles. E—the same as C, detail of cortex with ostia. F—principal strongyloxeas, general view. G–details of proximal and distal ends of a strongyloxea. H—intermediary and small tylostyles. Scale bars: A– B 10 mm; C 1 mm; D–E 0.5 mm; F–H 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 124, DOI: 10.5281/zenodo.18387
Suberites Nardo 1833
No full textGenus <i>Suberites</i> Nardo, 1833 <p>Diagnosis (sensu van Soest 2002):</p> <p>Sponges are massive, compact, usually with velvety smooth surface, caused by dense ectosomal arrangement of tylostyles oriented perpendicularly to the sponge surface, pointing outward; peripheral choanosomal skeleton consists of closely packed strands of tylostyles distinctly larger than ectosomal ones, with interior skeleton of densely packed unordered tylostyles. Centrotylote, minutely spined microstrongyles may be present in a few species and if so are concentrated at the surface.</p> <p> <i>Type species:</i> <i>Alcyonium domuncula</i> Olivi, 1792 (by original designation).</p>Published as part of <i>Plotkin, Alexander S. & Janussen, Dorte, 2008, Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic *, pp. 95-135 in Zootaxa 1866</i> on page 128, DOI: <a href="http://zenodo.org/record/183878">10.5281/zenodo.183878</a>
Acanthopolymastia Kelly-Borges & Bergquist 1997
No full textGenus Acanthopolymastia KellyBorges & Bergquist, 1997 Diagnosis (emended from BouryEsnault 2002): Sponges are cushionshaped or discoid, with a single low oscular papilla. The edge of the body is very hispid whereas the other part of the surface is only minutely hispid. The choanosomal skeleton is composed by tracts of tylostyles, subtylostyles or styles which project beyond the surface making up the hispidation. The cortical skeleton includes a palisade of small tylostyles. Acanthose microxeas are very abundant both in cortex and choanosome. Emendations proposed: 1) Spicules of the choanosomal tracts may be styles. 2) In all known Acanthopolymastia spp. the surface is hispid to a greater or lesser degree (see KellyBorges & Bergquist 1997). This hispidation is constituted by the choanosomal tracts projecting beyond the whole surface but not exclusively at the edge as given in Systema Porifera (BouryEsnault 2002). Moreover, the excess edge hispidation shared by A. acanthoxa (Koltun, 1964) and A. pisiformis (Lévi, 1993) is not found in A. bathamae KellyBorges & Bergquist, 1997. Type species: Atergia acanthoxa Koltun, 1964 (by original 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 98, DOI: 10.5281/zenodo.18387
Suberites topsenti Burton 1929
No full textSuberites topsenti (Burton, 1929) (Figs. 16, 17) Synonymy Suberella topsenti — Burton 1929: 446, pl. IV (fig. 5). Laxosuberella topsenti— Burton 1930: 675. Suberites montiniger — Topsent 1915: 39 –40; Koltun 1964: 25 –26; 1976: 169. Suberites topsenti —van Soest 2002: 242. Material examined SMF 10582 (1 specimen): PS 67 /078 11; SMF 10583 –10584 (2 specimens): PS 67 / 110 2. Description External morphology. Sponges are compact, massive, irregularly shaped (figs. 16 A–C). The dimensions may reach 35 x 15 x 11 mm. Surface is minutely hispid or velvety, greycoloured, with a single osculum of 0.4– 1 mm in diameter. Consistency is dense and compressible. Skeleton. The choanosomal skeleton is dense, confusedly reticulate, constituted by long spicules (fig. 16 D). The ectosomal skeleton is made of the smaller spicules arranged in bouquets (fig. 16 E). Spicules. Altogether 130 spicules from 2 specimens were measured. Two size categories are well distinguished (fig. 17 A). The number of measured spicules of each category is given below, separately for each specimen (n 1, n 2). Both long and small spicules vary from tylostyles to subtylostyles. They are straight, more or less slender, with terminal lobate tyles (figs. 17 B–E). The long spicules measure: length 857 1092 1368 µm, tyle diameter 1418.8 22 µm, diameter of the shaft underneath the tyle 8 13.0 18 µm, maximal diameter of the shaft 8 14.0 19 µm (n 1 = 40, n 2 = 30). The dimensions of the small spicules are: length 300479 743 µm, tyle diameter 14 17.0 27 µm, diameter of the shaft underneath the tyle 812.4 19 µm, maximal diameter of the shaft 1113.4 22 µm (n 1 = 30, n 2 = 30). Type locality: Antarctic: Ross Sea: McMurdo Sound, depth unknown. Distribution: Antarctic: Antarctic nearcontinent sectors (as S. montiniger: Koltun 1964; Sarà et al. 1992): NN 3 and 5 including the Western Ross Sea, as deep as 700 m. Northern Weddell Sea, ca. 2150–4700 m (present study). SW Atlantic: Burdwood Bank, 102 m (as S. montiniger: Topsent 1915); Magellan area, Falkland Islands (as S. montiniger: Sarà et al., 1992). Remarks In 1929 Burton erected a genus Suberella for a new species, S. topsenti described by him from McMurdo Sound, Antarctica. He also allocated the Antarctic specimens, previously identified by Topsent (1915) as Suberites montiniger Carter, 1880, to Suberella topsenti. In fact, S. montiniger had been originally described from the Arctic (Carter 1880). Burton (1929) considered Suberella to be an evolutionary step between Suberites and Pseudosuberites. Belatedly, Burton (1930) discovered that Suberella had been preoccupied by Thiele (1905), and erected Laxosuberella with type species L. topsenti as a replacement of Suberella topsenti. Koltun (1964; 1976) disagreed with Burton and reverted S. montiniger again. Herein we follow van Soest (2002) who recently advocated the validity of topsenti as a species, but placed it in Suberites. The taxonomic history of S. topsenti is described in detail by the latter author. We should only emphasize the lobate tyles of the subtylostyles in our sponges which have not been previously mentioned by any author, and the larger size of the choanosomal spicules in comparison with those observed by Koltun (1964) who did not distinguish two spicule categories either.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 pages 128-129, DOI: 10.5281/zenodo.18387
Rhizaxinella nuda Wilson 1925
No full textRhizaxinella cf. nuda Wilson, 1925 (Fig. 15) Synonymy Rhizaxinella nuda— Wilson 1925: 352 –353, pl. 38 (fig. 5). Description External morphology. Small clubshaped sponges with rather damaged stalks (figs. 15 A–E). Their height varies from 0.6 to 2.1 cm. The surface is velvety, greyish. Consistency is rather soft. A contracted osculum is located slightly eccentrically on the top of main body. Skeleton. The choanosomal skeleton is constituted by the principal tylostyles arranged more or less radially and grouped in tracts or bundles (fig. 15 F). The ectosomal skeleton is formed by the bouquets of small tylostyles, densely packed and intermingled. Skeleton of the stalk not observed because of considerable damage of the latter. Spicules. Altogether 120 spicules from 2 specimens were measured. Two size categories are well distinguished. The number of measured spicules of each category is given below, separately for each specimen (n 1, n 2). Both principal and ectosomal spicules possess welldeveloped spherical tyles. Principal tylostyles are slightly fusiform and straight (fig. 15 G). Their dimensions are: length 11501759 2318 µm, tyle diameter 17 18.9 21 µm, diameter of the shaft underneath the tyle 1314.3 15 µm, maximal diameter of the shaft 1316.2 21 µm (n 1 = 30, n 2 = 30). Ectosomal tylostyles are isodiametric, straight or slightly curved (fig. 15 H). They measure: length 450551 690 µm, tyle diameter 913.7 18 µm, diameter of the shaft underneath the tyle 7 9.0 11 µm, maximal diameter of the shaft 810.1 13 µm (n 1 = 30, n 2 = 30). Spicules of the stalk were not observed. Type locality: NW Pacific: Philippines: Mindanau Island: Iligan Bay, 814 m. Distribution (other than type locality): NW Pacific: Philippines: E. Cebu, 710 m (Lévi 1964). Antarctic: Northern Weddell Sea, 2080–2620 m (present study). Remarks We allocated the specimens studied to R. nuda due to the similarities of main body shape and skeleton architecture. However, it was done with some doubt because our sponges have smaller ectosomal tylostyles and thinner principal tylostyles than those described by Wilson (1925) and also we did not observe the stalk skeleton. On the other hand, our specimens differ quite noticeably from the Southern Hemisphere species R. australiensis Hentschel, 1909. The latter is characterized by the branching, anastomosing body and smaller sizes of both principal and ectosomal spicules than those of the specimens described herein.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 pages 126-128, DOI: 10.5281/zenodo.18387
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