Rossella nuda Topsent, 1901

Janussen, Dorte & Reiswig, Henry M., 2009, Hexactinellida (Porifera) from the ANDEEP III Expedition to the Weddell Sea, Antarctica, Zootaxa 2136, pp. 1-20 : 18

Rossella nuda Topsent, 1901

( Fig. 10 B)

Material examined: All from ANDEEP III Exped., Weddell Sea, Antarctica , SMF 10611a, SMF 10531, SMF 10612, SMF 10602 (3 specimens), SMF 10603, SMF 10706, R.V. 'Polarstern', stn PS67/074-7, 20 Feb. 2005, 71°18.48'–18.40'S, 13°58.55'–58.14'W, 1055– 1047 m, ethanol; SMF 10600, PS67/133-2, Weddell Sea, Antarctica , 16 Mar. 2005, 62°46.49'–46.38'S, 53°02.57'–03.50'W, 1584– 1579 m, ethanol.

Description and remarks: Fourteen specimens assignable to Rossella nuda were obtained on the ANDEEP III Expedition. These are mostly small sac-like forms, 26 to 93 mm in length, with smooth surfaces covered by long projecting prostalia. They agree in both morphology and spiculation with previous descriptions of R. nuda ( Topsent, 1901; Burton, 1929, 1932; Barthel & Tendal, 1994). Since the anisodiscohexasters of this species have never been well illustrated, an SEM ( Fig. 10 B) is provided to document their fine structure and to serve for comparison with those of other rossellids. This species is another very well known member of the Antarctic benthic fauna, with distribution including the Bellingshausen Sea, South Georgia Island, and from eastern Weddell Sea to the Ross Sea. It had previously been recorded from depths of 35–900 m ( Barthel & Tendal, 1994) but the ANDEEP III collections now extend the lower limit to 1579 m.

Figures

FIGURE 10. Anisodiscohexaster microscleres of (A) Rossella racovitzae (SMF 10705) and (B) Rossella nuda (SMF 10706) (SEM).