Filellum magnificum Pena Cantero, Svoboda and Vervoort 2004

Filellum magnificum Peña Cantero, Svoboda and Vervoort, 2004b

Filellum magnificum Peña Cantero et al., 2004b: 2287 –2289, figs. 2g –h, 5a–c; Peña Cantero 2010: 765, figs. 3d, e.

Type series. Holotype— Filellum magnificum Peña Cantero et al., 2004b, several hydrothecae on Billardia subrufa, with coppinia (RMNH-Coel. 30789) (Peña Cantero et al. 2004b: 2271, 2287).

Type locality. From the holotype, Weddell Sea, Antarctic, ANT II-4 Stn 502, 21 February 1984, several hydrothecae on Billardia subrufa, with coppinia (Peña Cantero et al. 2004b: 2271).

Material examined. German Polarstern Antarctic Cruises: ANT I-2 Stn 135, off Riiser-Larsen Ice Shelf, Princess Martha Coast, Weddell Sea (73° 41.6’S; 20° 55.3’W, 205m, 8 February 1983), on Stegella lobata (RMNH- Coel. 30779); ANT II-4 Stn 474, off Ronne Ice Shelf, Weddell Sea (76° 56.7’S; 49° 44.0’W, 220m, 14 February 1984), on Billardia subrufa (RMNH-Coel. 30788); ANT II-4 Stn 502, Weddell Sea (21 February 1984), on B. subrufa, with coppinia (holotype, RMNH-Coel. 30789); ANT VIII-5 Stn 16-481 (74.74° S; 61.13° W, off Ronne Ice Shelf, Weddell Sea, 620–640m, 15 February 1990), on spicules of a sponge (RMNH-Coel. 30802); ANT IX-3 Stn 158 (72° 21.8’S; 16° 42.1’W, off Cape Norvegia, Princess Martha Coast, Weddell Sea, 623m, 13 February 1991), on B. subrufa (RMNH-Coel. 30806). Spanish Bentart 2003 Expedition: Stn 5A, south of Peter I Island (68°56’37’’– 68°56’43’’S; 90°35’50’’– 90°35’19’’W, 124 m, 4 February 2003), on the ascidian Cnemidocarpa verrucosa, with coppiniae; Stn 8A, east of Peter I Island (68°50’05’’– 68°50’16’’S; 90°21’15’’– 90°21’16’’W, 85–86 m, 6 February 2003), on Schizotricha vervoorti, Symplectoscyphus glacialis and? Tubularia stem, with coppinia; Stn 8T, east of Peter I Island (68°50’08’’S; 90°21’17’’W, 87 m, 6 February 2003), on Schizotricha vervoorti, with coppiniae.

Description. (After Peña Cantero et al. 2004b: 2287): Colony stolonal, composed of creeping stolons giving rise to partially sessile hydrothecae. Hydrotheca tubular, sock-shaped, and adnate to substratum for just a tiny portion. Hydrothecal aperture circular, 169–208 µm wide; rim even and smooth, though indistinctly everted. Free part of hydrotheca, 436–670 µm long, directed upwards at varied degrees, frequently with few, long renovations. Adnate part of hydrothecae, 208–300 µm long, provided with a few striae on dorsal side. Cnidome consisting of two size-classes of nematocysts (e.g. ANT II-4 Stn 502): small (6.5–7.2 X 2.9 µm) and occasionally large (18.2 X 5.2 µm) capsules. In material from ANT VIII-5 Stn 16-481 only the small nematocysts were observed (5.9–7.2 X 2.6–3.3 µm).

Coppinia consisting of firmly adpressed gonothecae with defensive tubes. Gonothecae 423–455 µm long, 98– 111 µm wide, aperture circular, 52–58 µm wide, on a short and distinctly everted distal neck. Defensive tubes situated on periphery of the group of gonothecae, but also arising amongst them, and provided with large, distal, circular aperture.

Distribution. Filellum magnificum has been recorded only for the Antarctic, “at depths from 205 to 640 m […] south and east coasts of the Weddell Sea (off Ronne Ice Shelf, off Riiser-Larsen Ice Shelf and off Cape Norvegia, Princess Martha Coast)” (Peña Cantero et al. 2004b: 2289) and the south and east coast of Peter I Island, in the Bellingshausen Sea (Peña Cantero 2010).

Remarks. See Peña Cantero et al. (2004b: 2288–2289).